laptop batteries

Battery Chargers The (energy storage) capacity, C, of a battery is measured in ampere hours denoted a A-h (or mA-h for smaller types). The charging rate is normally expressed as a fraction of C - e.g., .5 C or C/2. In most cases, trickle charging at a slow rate - C/100 to C/20 - is easier on batteries. Where this is convenient, you will likely see better performance and longer life. Such an approach should be less expensive in the long run even if it means having extra cells or packs on hand to pop in when the others are being charged. Fast charging is hard on batteries - it generates heat and gasses and the chemical reactions may be less uniform. Each type of battery requires a different type of charging technique. 1. NiCd batteries are charged with a controlled (usually constant) current. Fast charge may be performed at as high as a .5-1C rate for the types of batteries in portable tools and laptop computers. (C here is the amp-hour capacity of the battery. A .5C charge rate for a 2 amp hour battery pack would use a current equal to 1 A, for example.) Trickle charge at a 1/20-1/10C rate. Sophisticated charges will use a variety of techniques to sense end-of-charge. Inexpensive chargers (and the type in many cheap consumer electronics devices) simply trickle charge at a constant current. Rapid chargers for portable tools, laptop computers, and camcorders, do at least sense the temperature rise which is one indication of having reached full charge but this is far from totally reliable and some damage is probably unavoidable as some cells reach full charge before others due to slight unavoidable differences in capacity. Better charging techniques depend on sensing the slight voltage drop that occurs when full charge is reached but even this can be deceptive. The best power management techniques use a combination of sensing and precise control 379 of charge to each cell, knowledge about the battery's characteristics, and state of charge. While slow charging is better for NiCds, long term trickle charging is generally not recommended. Problems with simple NiCd battery chargers are usually pretty easy to find - bad transformer, rectifiers, capacitors, possibly a regulator. Where temperature sensing is used, the sensor in the battery pack may be defective and there may be problems in the control circuits as well. However, more sophisticated power management systems controlled by microprocessors or custom ICs and may be impossible to troubleshoot for anything beyond obviously bad parts or bad connections. 2. Lead acid batteries are charged with a current limited but voltage cutoff technique. Although the terminal voltage of a lead-acid battery is 2.00 V per cell nominal, it may actually reach more than 2.5 V per cell while charging. For an automotive battery, 15 V is still within the normal range of voltages to be found on the battery terminals when the engine (and alternator) are running. A simple charger for a lead-acid battery is simply a stepped down rectified AC source with some resistance to provide current limiting. The current will naturally taper off as the battery voltage approaches the peaks of the charging waveform. This is how inexpensive automotive battery chargers are constructed. For small sealed lead-acid batteries, an IC regulator may be used to provide current limited constant voltage charging. A 1 A (max) charger for a 12 V battery may use an LM317, 3 resistors, and two capacitors, running off of a 15 V or greater input supply. Trickle chargers for lead-acid batteries are usually constant voltage and current tapers off as the battery reaches full charge. Therefore, leaving the battery under constant charge is acceptable and will maintain it at the desired state of full charge. Problems with lead-acid battery chargers are usually pretty easy to diagnose due to the simplicity of most designs. Comments on Building Charger for Small Lead-Acid Batteries The following applies to the sort of lead-acid batteries found in some camcorders and other portable equipment: The simple way is to build a power supply that outputs 13.8 volts regulated, with a current limit of 0.5 A. 13.8 V can be left connected to the battery forever without damage - this is called a float charge. The 0.5 A current limit protects the battery from drawing too much current and overheating if it's been deeply discharged. This sort of charger will get the battery back up to 80% charge within a few hours, so it's fine for most uses. 380 However, when designing it, make sure the charger doesn't self-destruct if the input voltage goes away (due to AC power failure) while still connected to the battery. With a standard series regulator, when the input power fails the whole battery voltage gets applied to the base- emitter junction of the output transistor in reverse. Many transistors are only specified to withstand about 6 V reverse base-emitter voltage, so with this design your charger will be toast at the first power failure. If you want higher-performance charging, there are special charge controller chips that provide 3 or more charge phases. They are:  Constant current charge at maximum safe current (see battery spec sheet) until the voltage rises to about 14.5 V.  Constant voltage charge at 14.5 V until the current drops to a fraction of the initial current limit.  Float charge at 13.65 V after that. By using the 14.5 V instead of 13.8 V for the initial charge voltage, this type of charger gets the battery back up to 90% charged in considerably less time. But if you only care about charging overnight, you don't need the extra complexity. On the other hand, NiCd batteries can safely be charged in less than an hour with suitable electronics. Lead-acid simply can't be recharged that fast. Substituting NiCds for Alkalines First note that rechargeable batteries are NOT suitable for safety critical applications like smoke detectors unless they are used only as emergency power fail backup (the smoke detector is also plugged into the AC line) and are on continuous trickle charge). NiCds self discharge (with no load) at a rate which will cause them to go dead in a month or two. For many toys and games, portable phones, tape players and CD players, and boomboxes, TVs, palmtop computers, and other battery gobbling gadgets, it may be possible to substitute rechargeable batteries for disposable primary batteries. However, NiCds have a lower terminal voltage - 1.2V vs. 1.5V - and some devices will just not be happy. In particular, tape players may not work well due to this reduced voltage not being able to power the motor at a constant correct speed. Manufacturers may specifically warn against their use. Flashlights will not be as bright unless the light bulb is also replaced with a lower voltage type. Other equipment may perform poorly or fail to operate entirely on NiCds. When in doubt, check your instruction manual. And, there is a slight, but nonzero chance that some equipment may actually be damaged. This might occur if its design assumed something about the internal resistance of the batteris; the resistance is much lower for NiCds than Alkalines. Can a Large Electrolytic Capacitor be Substituted for a NiCd? The quick answer is: probably not. The charger very likely assumes that the NiCds will limit voltage. The circuits found in many common appliances just use a voltage source 381 significantly higher than the terminal voltage of the battery pack through a current limiting resistor. If you replace the NiCd with a capacitor and the voltage will end up much higher than expected with unknown consequences. For more sophisticated chargers, the results might be even more unpredictable. Furthermore, even a SuperCap cannot begin to compare to a small NiCd for capacity. A 5.5 V 1 F (that's Farad) capacitor holds about 15 W-s of energy which is roughly equivalent to a 5 V battery of 3 A-s capacity - less than 1 mA-h. A very tiny NiCd pack is 100 mA-h or two orders of magnitude larger. Determining the Actual Capacity of a NiCd Battery Pack When a battery pack is not performing up to expectations or is not marked in terms of capacity, here are some comments on experimentally determining the A-h rating. When laying eggs, start with a chicken. Actually, you have to estimate the capacity so that charge and discharge rates can be approximated. However, this is usually easy to do with a factor of 2 either way just be size: Size of cells Capacity range, A-h --------------------------------------------- AAA .2 - .4 AA .4 - 1 C 1 - 2 D 1 - 5 Cordless phone .1 - .3 Camcorder 1 - 3+ Laptop computer 1 - 5+ First, you must charge the battery fully. For a battery that does not appear to have full capacity, this may be the only problem. Your charger may be cutting off prematurely due to a fault in the charger and not the battery. This could be due to dirty or corroded contacts on the charger or battery, bad connections, faulty temperature sensor or other end-of-charge control circuitry. Monitoring the current during charge to determine if the battery is getting roughly the correct A-h to charge it fully would be a desirable first step. Figure about 1.2 to 1.5 times the A-h of the battery capacity to bring it to full charge. Then discharge at approximately a C/20 - C/10 rate until the cell voltages drops to about 1 V (don't discharge until flat or damage may occur). Capacity is calculated as average current x elapsed time since the current for a NiCd will be fairly constant until very near the end. NiCd Batteries and the Infamous 'Memory Effect' Whether the NiCd 'memory effect' is fact or fiction seems to depend on one's point of view and anecdotal evidence. What most people think is due to the memory effect is more accurately described as voltage depression - reduced voltage (and therefore, reduced power and capacity) during use. 382 The following are the most common causes of application problems wrongly attributed to 'memory': 1. Cutoff voltage too high - basically, since NiCds have such a flat voltage vs. discharge characteristic, using voltage sensing to determine when the battery is nearly empty can be tricky; an improper setting coupled with a slight voltage depression can cause many products to call a battery "dead" even when nearly the full capacity remains usable (albeit at a slightly reduced voltage). 2. High temperature conditions - NiCds suffer under high-temp conditions; such environments reduce both the charge that will be accepted by the cells when charging, and the voltage across the battery when charged (and the latter, of course, ties back into the above problem). 3. Voltage depression due to long-term overcharge - Self-explanatory. NiCds can drop 0.1-0.15 V/cell if exposed to a long-term (i.e., a period of months) overcharge. Such an overcharge is not unheard-of in consumer gear, especially if the user gets in the habit of leaving the unit in a charger of simplistic design (but which was intended to provide enough current for a relatively rapid charge). As a precaution, I do NOT leave any of my NiCd gear on a charger longer than the recommended time UNLESS the charger is specifically designed for long-term "trickle charging", and explicitly identified as such by the manufacturer. 4. There are a number of other possible causes listed in a "miscellaneous" category; these include - o Operation below 0 degrees C. o High discharge rates (above 5C) if not specifically designed for such use. o Inadequate charging time or a defective charger. o One or more defective or worn-out cells. They do not last forever. To close with a quote from the GE note: "To recap, we can say that true 'memory' is exceedingly rare. When we see poor battery performance attributed to 'memory', it is almost always certain to be a correctable application problem. Of the problems noted above, Voltage Depression is the one most often mistaken for 'memory'..... This information should dispel many of the myths that exaggerate the idea of a 'memory' phenomenon." Memory Effect in NiMH Batteries? The party line is that Nickel-Metal-Hydride batteries do not have any memory effect. Perhaps, perhaps not. Care and Feeding of NiCds Here are six guidelines to follow which will hopefully avoid voltage depression or the memory effect or whatever: 383 (Portions of the following guidelines are from the NiCd FAQ written by: Ken A. Nishimura (KO6AF)) 1. DON'T deliberately discharge the batteries to avoid memory. You risk reverse charging one or more cell which is a sure way of killing them. 2. DO let the cells discharge to 1.0V/cell on occasion through normal use. 3. DON'T leave the cells on trickle charge for long times, unless voltage depression can be tolerated. 4. DO protect the cells from high temperature both in charging and storage. 5. DON'T overcharge the cells. Use a good charging technique. With most inexpensive equipment, the charging circuits are not intelligent and will not terminate properly - only charge for as long as recommended in the user manual. 6. DO choose cells wisely. Sponge/foam plates will not tolerate high charge/discharge currents as well as sintered plate. Of course, it is rare that this choice exists. All of which tends to support my basic operating theory about the charging of nickelcadmium batteries: 1. Man is born in sin and must somehow arrange for the salvation of his immortal soul. 2. All nickel-cadmium batteries must be recharged. 3. There is no proper method of performing either task (1) or task (2) to the satisfaction of anyone. Nickel Cadmium Versus Nickel-Metal-Hydride in a Nutshell NiCds are inexpensive, reliable, and easy to charge, but may suffer from voltage depression (what people call the memory effect) from repeated shallow discharge cycles. NiMHs have slightly higher capacity and no memory effect but have higher initial cost and are more sensitive to overcharging. Must be used with compatible charger. First Aid for NiCd Battery Packs CAUTION: Opening these battery packs will of course void any warranty but you knew that. Also, make notes of exactly how the cells and anything else inside is arranged. Improper reassembly can result in damage to equipment and/or risk of overheating should cells short inside the pack due to lack of or misplaced insulation. Under no circumstances should all thermal switches be removed - not only are they a safety device to prevent excessive temperatures but may also be part of the charging circuit. So, if they are removed, your next charge may be your last! I'd highly recommend that all of them be replaced (from another pack as a last resort) and installed in exactly the same positions they were originally. Many "name brand" camcorder and other similar battery packs contain two or even 3 thermal switches (those rectangular, un-identifiable, wired between the cells). They contain a bimetal strip operating a set of contacts which open at a preset temperature. 384 Often only one of these will fail, resulting in a $40 NiCad that won't charge. Since these little suckers are pricey if ya kind find them, a safe and cheap fix, is to test the thermal switches for continuity (they should be closed at room temp) and remove the defective one. If needed move the other, or at least one, to the mid-point of the cells series. If a battery pack has 8 separate cells, (i.e.: a 9.6 V VHS-C camera pack) the thermal switch should be wired between the 4th and 5th, and as far away from the charging contacts as possible. The extra switches were added as a safety factor but since the average one is designed to open at 87°C, there is no fire hazard so long as the pack is re-sealed after working on it. A quick fix for a NiCad pack left on the dashboard. Since good ol' solar power can heat a battery pack to the point where the thermal protection can open (and even warp a case) you can be stuck at the soccer game with what seems like dead batteries. The trick is to drop the temp below 87°C. Wrap the battery in plastic so the contacts won't get wet, and stick it in the cooler with the kids lunch and your six-pack. A few minutes and the thermistor should close. letting the batter work normally. Also, if the cord is long enough, never recharge a NiCad inside the car. Place the battery and charger under the car, in the shade, so it doesn't heat quickly and will get a full charge. Identifying Technology of Unmarked Battery Packs Since the nominal (rated) voltages for the common battery technologies differ, it is often possible to identify which type is inside a pack by the total output voltage:  NiCd packs will be a multiple of 1.2 V.  Lead-acid packs will be a multiple of 2.0 V.  Alkaline packs will be a multiple of 1.5. Note that these are open circuit voltages and may be very slightly higher when fully charged or new. Therefore, it is generally easy to tell what kind of technology is inside a pack even if the type is not marked as long as the voltage is marked. Of course, there are some - like 6 V that will be ambiguous. Powering LEDs with Batteries LEDs look like diodes with a high forward voltage drop. Above the that voltage, the incremental resistance is very low and without current limiting, the current would be critically dependent on the exact voltage of the power source. Most of the time, they are spec'd at a particular maximum current and need some means to limit the current to that value based on the input voltage. Some devices may depend on the internal resistance of the batteries to provide the current limiting - this is a poor approach and depends greatly on the type and capacity of the batteries being used. Most common is just a resistor but this provides no regulation and poor efficiency. Better designs (used in LED flashlights) will use a DC to pulse inverter with regulation achieving constant light output regardless of battery state-of-charge and high efficiency. LEDs can usually withstand short high current pulses and this allows the circuit to be designed with low losses. 385 The specifications for LEDs you see in electronics distributor's catalogs may look the same as those for incandescent lamps but they are not. Incandescent lamps provide their own current limiting; LEDs do not. It's possible to luck out and happen to have a given LED work without current limiting with a particular set of batteries but it hardly an acceptable design approach. Slight variations in battery parameters will result in gross changes in light intensity and possible shortening of life or outright destruction of the LED. Battery Problem Troubleshooting and Repair Problems with Battery Operated Equipment For primary batteries like Alkalines, first try a fresh set. For NiCds, test across the battery

All About Bios Password Removal

1 All About Bios Password Removal – Part I IBM Lenovo ThinkPad Password Chip 24RF08 P24S08 8-Pin This Password chip will remove the Supervisor password on any of the listed Laptops: This chip removes the BIOS / Power On / SVP Supervisor password and the follow errors: "0175, 0187, 0188, 0189, 0190, 0191, 0192, 0195, 0196, 0197, 0199, 0271, 0176, 0260, 0270" on your ThinkPad notebook IBM / Lenovo Thinkpads: T61, T61p, R61, R61i, X200, X200s, X300, X301, R400, R500, T400, T500, W500, W700 2 The Chip is ready to go straight in and has no password set. What you need to do: 1. disassemble the laptop 2. find the right chip 3. remove the old chip and solder the new one on place 4. re-assemble the laptop. That's it! It is so easy!!! Toshiba Laptop BIOS password Recovery Toshiba laptops aren’t like most laptops where you can remove the BIOS battery and let it sit for a few hours to reset the BIOS. So what do you do? There are three forms of BIOS password removal being used currently by Toshiba: 1. Parallel port wraparound connector 2. Shorting a jumper, with power and with no power 3. Challenge/Response code Method 1. Printer Dongle Method: Works with Portege, Satellite, Satellite Pro, Tecra and Libretto Laptops of the following model numbers : 100(1xx) 200(2xx) 300(3xx) 400(4xx) 500(5xx) 600(6xx) 700(7xx) 1000(1xxx) 2000(2xxx) 3000(3xxx) 4000(4xxx) 7000(7xxx) 8000(8xxx) (A15-S 127) (1415-S 173) SERIES & Some DVD Models The “xxx” above means that each x can be any number, i.e. 1xx could be 101, 103, 111, 112 etc. * First cut a plug from an old DB25 printer cable, and open the casing of the plug. This is how the pins look: 3 * Now connect: o Pin 1 to Pin 5 and to Pin 10 ( go from 1 to 5 and from 5 to 10) o Pin 2 to 11 o Pin 3 to 17 o Pin 4 to 12 o Pin 6 to 16 o Pin 7 to 13 o Pin 8 to 14 o Pin 9 to 15 o Pin 18 to 25 It should look something like this: 4 Plug it in and bootup 5 METHOD 2. Shorting a jumper: In order to clear a BIOS of Compal manufactured units you need to use the NO POWER method, units manufactured by Inventec need to be to be POWERED ON to rest the BIOS. To reset Compal units: 1. Turn off the POWER 2. Remove the battery and power cord 3. Peel back any black mylar (if any) covering the jumper 4. Using a flat screwdriver, short the jumper by connecting the two jumper points 5. Reset the computer and verify the BIOS has been reset, if not then repeat steps Inventec units can skip steps 1 and 2 METHOD 3. Challenge/Response Code: The challenge/response code method consists of matching a Challenge code ( power the machine up,press ctrl,then tab,then ctrl, then enter) generated on your machine and matching a Response code generated by Toshiba and calling a Toshiba Tech Support Agent. added 5/31/10: 6 Satellite p100 and pro p100 : with laptop off,remove wifi card and short pads marked jp8 for 10 secs satellite l10,l20,l30 and pro l20 : with laptop of short pads marked jp1 for 15 secs (l20 short pads marked g1) satellite m100 and tecra a6 : with laptop off ,remove memory and insulation under memory and short pads marked clr1 for 15 secs (satellite 17** series,1100,1110,1130, 1200, 1900, 2430, 3000 P20,P30, P33, A30, A70, A80, M40X, M50,M60, M70, M100)as above tecra a3,s2,a5,a6 : pads are by memory modules and will be labeled J1, J2, J5, J7, J9 or clr1 satellite a100,tecra m7 : remove keyboard and short pads marked c88 while turning laptop on, remove short as soon as Toshiba logo appears Satellite A100 (PSAA2A-02C01N) : Remove Memory Cover from base of machine Release & remove right side Memory Module, Lift black plastic insulation Locate & short PAD500 Pin 1 & 2 together, Power on machine while still shorting Pin 1 & 2 As soon as the TOSHIBA logo appears, remove short TECRA A4 & Satellite M40 Open modem & Wi-Fi card cover, Remove mini PCI Wi-Fi card Lift up black plastic, Locate & short C738 Pads 1 & 2 together Power on machine while still shorting Pads 1 & 2 As soon as the TOSHIBA logo appears, remove short tecra s1 : TECRA S1 Open palm rest cover,Remove mini PCI Wi-Fi card Lift up black plastic,Locate & short C5071 Pin 1 & 2 together Power on machine while still shorting Pin 1 & 2 As soon as the TOSHIBA logo appears, remove short 7 Shorting Bios Password For Dell Laptop Series 1. The laptop 2. A small screwdriver 3. A paperclip Introduction This is the prepatory section where I explain some things about the chip, CMOS, asset and service tags, and passwords; so that you will have a good grasp of the big picture. Hopefully it will also clear up any thing you have gotten a vague idea about on another website. All computers have special chips inside them that store information about the computer. Some of them are manufactured with permanent information that can not be changed (and, as a rule, all have exactly the same information on them; thus not for passwords.) These contain information about the computer model or are part of its functional circuitry. Another type of chip (the kind we are interested in) is manufactured with a blank information area that can be programmed or filled with information. These chips are commonly used to store settings and passwords; and come in 2 basic sorts: VOLATILE and NON-VOLATILE. 8 VOLATILE chips use a source of electricity to help them keep their information, such as a battery. They are less expensive and are used to store computer settings, and also passwords on most computers. If one of these chips has a password on it, the battery can be removed and after a time (between 2 seconds to 30 minutes, depending on the chip) the password will be erased. NON-VOLATILE chips do not need electricity to keep their information, but are more expensive. If there is a password on one of these chips, it can be removed from power for years and still have the password on it. (However this does not mean that it is permanent.) Remember that the information on Non-Volatile chips can be filled with information. This information can also be changed or erased. If you have read this far you probably own a Dell or similar laptop with a password that is obviously stored in a Non-Volatile chip, or are an employee of a company that makes one. These laptops have most of their setting information stored in Volatile (inexpensive) chips, and their passwords are stored on a tiny Non-Volatile (more expensive) chip. The chip that Dell uses is called a 24C02 chip. This is the Chip Type number used to refer to the chip's design in the electronics industry. The 24C02 is a small, rather common surface mount* dip* chip with 8 leads (or legs), which costs about $5. It measures 4.5 mm long x 3.5 mm wide x 2 mm tall, and stores 256 Bytes (or one quarter of a Kilobyte) of information. It is commonly used in modems, DIMM Memory, and other electronic devices; and in a different shape it is used in many wallet sized "smart cards." * SURFACE MOUNT means that the chip is soldered onto the surface of the printed circuit, instead of having pins sticking through the board. This is the most difficult type of circuitry to solder by hand. * DIP means 'Dual Inline Package'. This means that the chip has 2 rows of leads (or legs) in straight lines running down its sides. That's the chip we will be dealing with, if you would like to know more about the chip, click here, or read the "Some unnecessary information about the chip." section later on. The laptop that was used in this demonstration is a Model 630 type PPX. Other laptops may be different from the one shown in the full breakdown demonstration photos. The following links provide in depth information on specific models: Removing and Replacing Parts: Dell™ Latitude™ CP and CPi Removing and Replacing Parts: Dell™ Latitude™ C600/C500 Series Service Manual Removing and Replacing Parts: Dell™ Latitude™ C800/C805 Service Manual Removing and Replacing Parts: Dell™ Latitude™ C810 Service Manual 9 If a certain laptop does not correspond to any of these diagrams, more information might be found on the web, or, anyone not reading for informational purposes only - could decide to simply "Wing it." Also, the chip containing the password may be in a different location on some motherboards, but it should be able to be found by reading the numbers on the top of the chip, although a magnifying glass might be necessary. ** --- UPDATE --- ** I have information about other models of Dell laptops now. Thanks to people's e-mail information, I can now tell you more about other models of laptops. Here is a list of different models showing what I know about them and don't as pertains to the chip and this procedure. I am adding short pages of special procedures for certian other models when I can get my hands on them. Please read through the entire main site's procedure before you attempt any of these subprocedures. Model / Series Type Number Chip Clears Comments Procedure Latitude XP ? ? X Latitude XPi Yes Yes X Latitude CP Yes ? X Latitude CPi Yes Yes The chip is under the processor. Latitude CPiA Yes Yes The Chip is on the top side of motherboard, under MMC2 processor module. X Latitude CPx Yes Yes X Latitude CPxJ Yes Yes The Chip is on the top side of motherboard, under MMC2 processor module. X Latitude CS ? ? X Latitude CSx Yes Yes The hard drive on this laptop may lockup after procedure. (don't know for sure) reported not to have service tag or serial #. X Latitude c400 Yes ? X Latitude c500 Yes Yes The Chip is on the bottom side of motherboard, under the PCMCIA card slots. X Latitude c510 Yes ? The Chip is on the bottom side of motherboard, under the PCMCIA card slots. X Latitude c600 Yes Yes The Chip is on the bottom side X 10 of motherboard, under the PCMCIA card slots. Latitude c610 Yes Yes The chip is located near the DIMM 1 memory slot. Latitude c640 ? No The Chip is on the bottom of the motherboard just to the left of DIMM 1. X Latitude c800 Yes ? X Latitude L400 Yes Yes You can clear the password from this laptop simply by removing that CMOS Battery for 5 minutes. See procedure. Inspiron 2650 ? ? X Inspiron 600m Yes Yes This Laptop may have another number on the chip, located near the processor. X Inspiron 3200 Yes No A program called KILLCMOS.EXE is reproted to work for this laptop. X Inspiron 3800 Yes Yes The Chip is on the top side of motherboard, under MMC2 processor module. X Inspiron 4000 Yes Yes The Chip is on the bottom side of motherboard, under the PCMCIA card slots. X Inspiron 5100 ? ? X Inspiron 7000 24C164 No This is a different chip and probably a different type of password circuit. X Inspiron 7500 Yes No X Inspiron 8000 Yes No The chip is under the CDROM X Inspiron 8100/8200 Yes Not Certain The chip is located under the keyboard. Inspiron 8500 ? ? X Omnibook 6000 ? ? X Now we are informed and ready to begin. Anyone attempting this procedure should have the implements shown in this picture, along with any others they may deem needful or useful. They may also wish to write down the Service Tag number for later use, as it will be erased. 11 Laptop - Screwdriver - Paperclip And remember, when using a screwdriver, it's "righty - tightey, lefty - loosey." 12 Taking it apart Step One This is the first step in the procedure; and demonstrates how the laptop is prepared for disassembly, and begin the actual disassembly process. For this particular laptop, a size 0 Phillips™ screwdriver is recommended. Other models may require a different size or type. *note: These photographs show the procedure being performed without any special devices or methods used to prevent or reduce the risk of either personal injury or damage to the device; such as safety goggles, electrostatic wrist bands. It is not the purpose of this website to promote, assure, or condone this or any procedure as being safe or reasonable without the use of such devices or methods. Anyone performing this or any similar procedure is responsible for seeing to the safety needs of and resulting from such a procedure. Furthermore, on the subject of Electrostatic Discharge (ESD,) and potential damage to computer chips or circuitry: During the past 5 years that I have worked as a computer technician, apart from volatile memory (SIMM / DIMM modules,) I have never needed to use ESD reducing devices, nor known any computer device to fail due to the effects of ESD from handling or use without ESD reducing equipment. This may, in part, be because I live in an area where the average humidity is around 70% - 80%. I understand that increased humidity tends to lower ESD effects, while lower humidity tends to increase this. Anyone deciding to perform this procedure must make their own decisions about the importance of ESD in their environment and the need for special devices or procedures. 13 (Remember that SIMM / DIMM memory modules / sticks are always extremely susceptible to ESD damage at any humidity, under any environmental conditions, and should always be handled with the utmost care and precaution against damage.) The first thing that needs to be done, is the removable of any batteries, floppy drives, CD-ROMs, PCMCIA cards, or other removable / swappable components of the laptop. Also the power cord / adapter should be disconnected. One may, or may not want to remove the RAM, depending on personal preference. If possible, the hard drive should be removed as well. First the hard drive retaining screw is removed like this: 14 Removing the hard drive will prevent any erroneous information that may develop while working with the chip from causing a password to appear on the hard drive, or from changing an already known hard drive password I do not know of any method for sucessfully removing a hard drive password, or discovering what the password on a hard drive might be. The hard drive caddy cover is pressed down (towards the bottom of the laptop,) unlocking it. The hard drive caddy is pulled and slid outwards until it is free from the laptop assembly. 15 The next thing that needs to be done is the removing of the keyboard. (This particular model) The keyboard is released from the rest of the assembly by the removal of 7 screws on the bottom of the laptop. These are indicated here by blue arrows: 16 They are also indicated on the bottom of the laptop by a circle with the letter 'K' inside of it next to the location of each screw. The keyboard is then lifted upwards and out of the main laptop assembly, except for 2 thin connection cables. The keyboard can then be lain perpendicular to its original position so that these cable's connectors can be accessed. 17 The larger cable pictured here can be pulled straight up, disconnecting it from the main board. 18 The retention clip of the smaller cable must be pressed on both sides (in the direction of the cable) gently. It should not be forced, and when open, will still be attached to the main connector, but be moved approximately 1 - 2 mm from its original position. 19 The cable can then be pulled from the connector. Taking it apart, continued Step Two The rest of the disassembly process. The next thing that needs to be done is removing of the palmrest. (This particular model) The palmrest is released from the rest of the assembly by the removal of 5 screws on the bottom of the laptop. These are indicated here by red arrows: 20 They are also indicated on the bottom of the laptop by a circle with the letter 'P' inside of it next to the location of each screw. The electronic components of the palmrest are disconnected from the main circuit by pulling this tab, which contained one of the keyboard connectors on it, straight up away from the main circuit board. Also, if the CMOS information needs to be cleared for any reason, it can be done by disconnecting this connector for only a few seconds. This is because the battery is located in the palmrest just above the right speaker (at least on this model.) And because this particular CMOS chip doesn't hold its data very long without a battery, and is located on the main board. I personally found this to be somewhat odd. 21 Now the latch pictured here must be released from its hold on the bottom of the case. I used a small flat screwdriver to gently pry it back while easing the front of the palmrest upwards. Be careful not to lift the palmrest up too much, as there are still 2 more hitches securing it to the rest of the case. There are 2 latches, one on each side of the palmrest. They are towards the back of the palmrest, near the screen. They can be unhooked from the main assembly in the manner shown in this picture, by lifting the corner of the other section of the case up about a millimeter. After both of these are freed the palmrest can be lifted away. 22 The official repair manual for this laptop stated that the display must be removed before the palmrest can be taken off. But, as you can see, for anyone who is mechanically inclined enough to be able to cross a country road, this is not actually necessary. (Although this procedure does require the removal of the screen, which is next.) The first thing that needs to be done when removing the screen is to disconnect this ribbon cable from its connector on the motherboard by pulling it upwards. This is the only electronic connection that the screen has with the rest of the notebook. 23 To release the screen from the main assembly, the 3 screws shown here by red arrows, and also by a circle containing the letter 'D' next to each screw. Make sure you keep track of all screws, put them in something, and keep track of which ones go where. After these screws are removed, the screen can be lifted straight up and away. 24 The motherboard is the next part to be removed. This model has 2 screws fastening the motherboard to the case as shown in the picture. There are 2 more photos following, which show close-ups of each screw to avoid any confusion. They are shown by red arrows in the photographs. But, unlike previous screws, they do not have a convenient circled letter next to them. * For this model, these are the only screws that need to be removed on the motherboard! There are other screws which may look as though they need to be removed, such as the ones by the processor or fan but these should not be removed. 25 Remember to check the next 2 pictures first. The screw on the right. The screw on the left. 26 The motherboard is now released from the bottom of the case and the unit is placed in its normal position on a flat surface. 27 Applying a steady gentle lifting force under the middle fore section of the motherboard causes it to swing up. Reorienting things just a tad Step Three In order to clear the password on the chip, some of the laptop must be put back together. This is because the laptop will need to be powered on during the process. Seeing how easy it was to disassemble, this is not a difficult task. This page shows how this part of the procedure is done, and the next page is where the real action of actually clearing the password takes place. 28 First the display screen must be put back on. This can easily be done by holding it in this manner and setting it into its slot. Then it must be held in place with screws, one on each side as shown in this picture should be sufficient to hold it. Up to this point we have something that looks like this: 29 Now the palmrest is be put back on. 30 The video connector is plugged back in. And the palmrest connector is also plugged back in. 31 The keyboard is also reconnected. The smaller Keyboard cable is slid back into its connector, and is held fast by closing the connector as shown is this picture. The larger cable is then gently pushed back onto its connector. The keyboard is placed back in its seating, like this: 32 And finally, this one screw is used to hold the keyboard in place while the work of clearing the password is performed. 33 Now the laptop is ready to and there is free access to the password chip which is located on the bottom of the motherboard. 34 Now, you are probably thinking to yourself 'Wait a minute! I just put almost the entire laptop back together! The wascally wabbits that made this thing sure made it difficult to get to that chip!' OK, so, you're probably not thinking the part about 'Wascally Wabbits'; but, yes, this is somewhat of a study in redundancy. The good news is that it's almost done. Nothing more has to be bought, soldered, or disassembled.

1 Networking: A Beginner's Guide Course Content Introduction What is a LAN? What equipment is necessary for a LAN? Physical Network Setup Quick Way to Configure DSL Modem in Bridge Mode IP Logical Network Design Router Configuration DHCP DMZ and Port Forwarding Making Sure TCP/IP Works How to Connect 2 Computers Directly Using Crossover Cable Quick Way to Configure IP Address and Network Information in Windows 7 Manual IP Assigning IP Assigned by DHCP server Configuring IP Address and Network Information in Windows Vista How to Set IP Address and Network Information in Windows XP How to differentiate straight and crossover cable Troubleshooting Network Problem: Cannot Connect to Wireless Network? Using Ping to Troubleshoot Network Problem Using WinSockFix to Fix Windows XP Networking Problem 2 Introduction With computers getting cheaper and cheaper these days, it is not uncommon for a household to have more than one PC. If that describes you, then you have probably found yourself in the situation where you wished you could access the other PC to retrieve a file, use the printer attached to the other PC, play multi-player computer games, or most importantly share your broadband Internet access such as cable or DSL modem with the other PC. To accomplish this all you need is a home network where you connect two or more PCs What is a LAN? LAN stands for “Local Area Network.” Basically, it is a communications link between two or more computers to share information with each other. Although “Local Area” seemingly implies that LANs are always small, this is not always the case. A LAN could possibly consist of thousands of computers provided that they are all connected through the same network connection and are directly linked through hubs and switches. However, once a router becomes involved, the definition of LAN no longer truly applies and you may call a computer connected to another through a router a member of an Internetwork, or if it is part of the main Internetwork, the Internet, and a computer connected to the Internet. The Internet in general can be thought of as a great LAN with all of its members indirectly connected in a giant mesh with each other. 3 It is important to understand a bit about Networking in order to actually “build” or put together a Local Area Network. Every member of a network possesses an IP address, or a unique identifier of that computer which no other computer or node of the network can use. When a dial-up user connects to the Internet, he or she is either in use of or is dynamically assigned an IP address, which follows the following structure: xxx.xxx.xxx.xxx …Where each “xxx” is a three digit number from 0 to 254. For example, 163.56.52.199 is a valid IP address, while 53.275.41.3 is not, because 275 is above 254, which is the range of an IP address. This number is used on the Internet to specifically identify your computer. However, within a network, you use a special type of IP address. Although this is certainly not the correct terminology, I will refer to this as the “Internal IP” in this guide. I call it this because the Internal IP uses a special format: 192.168.xxx.xxx [most common in LAN's] or 10.xxx.xxx.xxx [common in large LAN's] or 4 172.16.xxx.xxx – 172.31.xxx.xxx [uncommon] Each of these Internal IP blocks, or groups of addresses, is specifically reserved for Internal IP addresses. What exactly is an Internal IP address? An Internal IP address is the IP address that a computer uses to communicate with other computers or nodes in a network. Think of it as the Office of the President. In the White House, there are many personnel that operate inside of it. However, there is only one true outlet – the President and his PR team. In this metaphor, each of the computers in the network is a member of the personnel of the White House. Amongst each other, they are free to communicate and all have (somewhat) of their own identity and voice. To the rest of the world (the Internet), however, your computer and all of the others in your network are represented through your WAN Address, or the IP address assigned to you by your Internet Service Provider. In other words, Juan, Joe, and Mike may have the Internal IP addresses 192.168.1.5, 192.168.1.77. and 192.168.1.83; however, when they surf the Internet, they are always represented as their WAN Address 24.54.51.146. 5 What equipment is necessary for a LAN? There are some basic equipment needs for a Local Area Network. These include the communication cards to connect the network plugs into (known as Network Interface Cards, or NICs), the cables to connect between nodes (known as CAT5 cables), the switch to connect all of the nodes to, and the router to connect the switch to the Internet (therefore, indirectly connecting each of the nodes to the Internet). Note that the switch and router are often combined in to a single unit these days. 6 For the most part, choosing a NIC is rather simple. In many cases your computer or motherboard may already possess one. However, in the case that you need to purchase a NIC, buy a cheap 10/100 NIC (you can find one at many retail outlets for under $20.00) or a nicer 10/100/1000 NIC. The only reason you would possibly want a 10/100/1000 NIC is if you planned on buying one to keep for more than a year or so, and are anticipating your own purchase of a gigabit switch. I would recommend buying a 10/100/1000 NIC if you can, but 10/100 would of course suffice in most circumstances. Cabling is never a serious issue these days. Just be smart enough to buy one that you know is right for your location (i.e. a five-foot cord won’t suffice in most circumstances, whereas a 1000- foot monster may not be such a great idea for your home LAN). The main issue at hand is the switch/router. I say this because there are many switch-router combinations each with their own merits. However, for the value, I would highly recommend the Gigafast or Netgear line of products appropriate for your network size. Something that you must understand is that networks have very little to do in physical configuration and almost everything to do with software and settings. Every switch/router has its own configuration software that is usually based off of the HTTP protocol (or in other words, accessed through a web browser). So, depending on the switch/router you choose, the configuration software for that switch/router will vary. Building The Network The most common home network is Ethernet, it’s a very popular LAN (Local Area Network) technology due to it’s inexpensive setup cost and reasonably fast speed. The other types of network are Token Ring, LocalTalk, and FDDI. The speed (data transfer rate) of an Ethernet can be 10Mbps (Ethernet), 100Mbps (Fast Ethernet) and 1000Mbps (Gigabit Ethernet). Mbps is called Megabits per seconds. From my opinion, 100Mbps speed might be sufficient for your network needs. There is one rule here, make sure all your network devices (router, network card, switch, hub, network cable) are able to support the network with particular speed (10Mbps, 100Mbps, 1000Mbps) which you plan to set up. If you plan to set up a Gigabit Ethernet, although you have 100Mbps' network card, but your router can only support 100Mbps, then the network speed would be 100Mbps. 7 Here is typical network topology Physical Network Setup 8 Ok, for your home network, it’s time to do some exercises, here is how I do physical network setup. I will use D-Link's DI-604 broadband router as an example. You can use other type of router according to your needs. Please prepare some straight network cable as well. Connect the WAN port on router to your cable/DSL modem using straight cable, then connect computers’ network card to router’s LAN ports using straight cable also. You can connect up to 4 computers to this router. Power on the router after finish connecting, you should be able to see the WAN and LAN lights on the router. Also you need to ensure that your DSL/Cable modem is configured in bridge mode, so that it can work well after connecting to router. Quick Way to Configure DSL Modem in Bridge Mode This briefly explains how to configure DSL modem in bridge mode from a computer, so that the computer can access to Internet by using dialer. This is very common setup after you have subscribed new DSL broadband service, you just need to configure the modem as a bridge, and after that configure PPPoE dialer in Microsoft Windows by providing username/password or other network information for accessing Internet. If you plan to connect the modem to router and set up a home network, you must set bridge mode on modem too. Here is the way we configure the DSL modem: 1) Connect DSL modem’s LAN port to computer’s network card by using straight through network cable. 9 2) Read the modem manual, find out the default modem IP address, after that you need to set computer with the IP address in same network with modem, so you can access and configure it. As an example, if the modem IP is 192.168.1.1, I set computer IP as 192.168.1.10 (you can set 192.168.1.X, X= number between 2 and 254), netmask as 255.255.255.0 and gateway as 192.168.1.1. 3) Open a web browser and key in http://DSL-modem-default-IP (example: http://192.168.1.1) into the address bar, after that hit Enter key. 4) The modem logon screen will appear, type in default username and password you found in modem manual. You will then log on to the modem management page. 5) Go to the correct configuration page by referring to modem manual, and then set the operation mode to Bridge mode. Here is an example: 6) The other important info for modem to work well is Virtual Path Identifier (VPI) and Virtual Circuit Identifier (VCI), you need to set these numbers correctly. If you get the modem from ISP, most likely it’s been pre-configured correctly. If you are not sure, have a look on common VPI and VCI used by different ISPs. Here is an example: 7) Ok, at this stage you have done the modem configuration, you can then proceed to configure PPPoE dialer on connected computer. or wired), you can then proceed to configure that wireless router or Ethernet wired router. . 10 After setting up the network, we need to decide what IP addresses need to be used for router and computers. IP Logical Network Design IP logical network design! This is one of the task which you need to do is do after you have decided to set up a network (wired or wireless) at home. This is the process to decide the IP addresses, netmask for your computers, router and other network devices. Since each IP address assigned to your computer must be unique, you can’t simply assign an IP address to your computer. Here are 3 recommended IP ranges you can used in your network. These 3 blocks of private IP address space are reserved by Internet Assigned Numbers Authority (IANA) for private network, such as home network. 3 Private IP address space: 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255 You can use these 3 Private IP address space in your network without worrying it will conflict with the IP addresses in Internet. After deciding the IP addresses to be used, let’s decide what netmask to be used. Netmask will decide how many IP addresses available to be used in your network. I usually use 255.255.255.0 for having 254 addresses to be assigned. There is a network address and broadcast address which can’t be used for IP assigning. Network address is used to represent that particular created network, whereas broadcast address is used to talk to all computers in that particular network. Below are some examples for assigning IP addresses in your network. 11 Example 1: I have 5 computers and a router in my network. I will assign 10.0.0.1 to the router, 10.0.0.2 – 10.0.0.6 to other 5 computers. I use netmask 255.255.255.0 for this network, so that I can assign IP addresses 10.0.0.1 - 10.0.0.254 in the network. Network address is 10.0.0.0, broadcast address is 10.0.0.255. Example 2: I have 8 computers, 2 notebooks and a router in my network. I will assign 172.16.10.1 to the router, 172.16.10.2 – 172.16.10.9 to other 8 computers and 172.16.10.10 – 172.16.10.11 to other 2 notebooks. I use netmask 255.255.255.0 for this network, so that I can assign IP addresses 172.16.10.1 – 172.16.10.254 in the network. Network address is 172.16.10.0, broadcast address is 172.16.10.255. Example 3: I have 8 computers, a router and a network printer in my network. I will assign 192.168.1.1 to the router, 192.168.1.2 to the network printer and 192.168.1.3 – 192.168.1.10 to other 8 computers. I use netmask 255.255.255.0 for this network, so that I can assign IP addresses 192.168. 1.1 – 192.168.1.254 in the network. Network address is 192.168.1.0, broadcast address is 192.168.1.255. Try this online simple IP calculator. http://www.subnetmask.info/ Try to enter network address 192.168.1.0 and number of subnet 1, then click calculate. You will get detailed information about this network. Try it.. If you wish to learn more about IP or network subnet, here is useful IP and subnetting site with video presentation. http://www.learntosubnet.com/ For the setup that I’m using, I will use IP addresses 192.168.1.1-254, netmask 255.255.255.0. Install the NIC in its proper place. If it is a PCI card (which it probably will be), make sure it is in snug. 12 Make sure that you place the switch/router in a central location such that each of your nodes has easy access to the switch/router. If the RJ-45 plug is connected on both ends, the light on the switch/router should light up under which port you are using. Do NOT place anything in the uplink port. Power up the switch/router and get ready to rumble. A Note About Windows XP Now that all of your computers are plugged into the network and everything is powered and fine and dandy, you should probably start thinking about the software configuration of your LAN. Assumed in this tutorial is that you have Windows XP. Now, it is obvious that not every single PC user today uses Windows XP. However, the majority of users do, and for the purposes of this guide, I believe that instructions for XP will suffice because many of the instructions used in this configuration tutorial are extremely similar on both Windows 9x and NT/2000 operating systems. Router Configuration 13 Now, load up your Windows XP installation. If everything is physically set up correctly, Windows should “automatically” detect and configure your network connection. That’s it, right? Of course not. Actually, more important than client configuration on any network is the much- feared router configuration process. The router configuration process utilizes the HTTP or Hyper Text Transfer Protocol as an interface to the router’s internetworking operating system. Basically, what that means is that you will interface and configure the router through a web browser. However, here is the fundamental paradox: how is it possible to interface with a router using HTTP when your network is not properly configured in the first place? Hopefully, Windows XP has correctly detected your network settings. Go to Start -> Run and then type in “cmd” to get the almighty command prompt. From the command prompt, type in “ipconfig /all.” If your default gateway is not 0.0.0.0, then type in that IP into your web browser preceded by the “http://” string. Most likely it will be 192.168.0.0, 192.168.0.1, 192.168.1.0, 192.168.1.1, or 192.168.254.254. Whatever the case, once it loads, it will most likely load an authentication applet. Refer to your router’s documentation for this default password. Once your credentials have been accepted by the router, you are ready for action. Now, herein lies a complicated dilemma for this guide. On one hand, it would be easiest for the reader of this guide to read each individual router’s particular method of configuration and such. However, on the other, to cover each and every router would take years. So, refer to router’s documentation when you doubt a reference or in lack of knowledge of the meaning or location of a particular setting. DHCP One of the fundamental concepts of the LAN is the concept of IP addresses. Now arises the question: how exactly are they assigned? The answer is through DHCP. DHCP stands for Dynamic Host Configuration Protocol and basically is used to assign nodes on the network IP addresses automatically such that none conflict with each other (i.e. two nodes sharing the same IP), are legal (i.e. not 192.177.454.4), and are sometimes even in order (192.168.1.10- 192.168.1.20). DHCP works on a client-server level, in that the client (a node on the network) requests a “lease” on an IP from a server (usually the router). The server grants the node a specific IP. Now, you may or may not want to employ DHCP in your LAN setup. There are numerous advantages to DHCP, the foremost being that there is a much lessened chance of two nodes identifying with the same IP address. It is also self/automatically configuring and a very 14 reliable server. In the case that you choose to use DHCP, configure DHCP for which IP addresses you wish it to give leases to start upon and end upon. DMZ and Port Forwarding Now, after DHCP is configured, every member of your network can now be assigned a unique IP address internally. However, externally, the Internet still may need to contact a specific computer in your network for a specific purpose. These purposes include things from Counter-Strike and UT2004 to web servers and MySQL databases. So, how does a computer on the Internet know how to specifically contact a computer in your network (which, through a router, a million computers could potentially be hidden under one IP address)? The port system of TCP/IP provides this option. TCP/IP works on a system of IP addresses and port numbers. Port numbers are specific “holes” or entries to a node on a network for a specific purpose. Ports are infamous for their reputation as “security holes” because it is often through useless open ports that worms spread so powerfully, dangerously, and easily. Now, for example, let’s say you needed to host a file server through FTP. After setting up the file server on your desired node, you will need to find the IP address of that specific node. Then, go to the port forwarding section in your router’s configuration setup dialogue and fill in the port forwarding form accordingly. Remember that FTP operates on Port 21. There is, however, another option. Suppose on your network there is one computer or server that is so important that you feel you cannot individually specify which ports to forward to this computer on, you can set it as the almighty DMZ host. The DMZ host takes all of the non-forwarded ports and sends them straight to the DMZ Host instead of the router itself. The DMZ host role can be fulfilled by anyone, but 15 generally speaking, being the DMZ Host is an invitation to be paid a visit from Bubba the Hacker. It is a wide-open computer system. Just for your information, another term for the “Port Forwarding” section of your configuration software is “Services Configuration.” Now that you have finished with the configuration of your router, you can move on to the configuration of your client. Pray for the Best Windows XP almost always can automatically determine and detect a network connection. To see if it has detected your connection, go to Start -> Control Panel -> Network Connections. Look for the “LAN or High Speed Internet” heading and find your LAN connection under the listing. Note that VPN and 1394 Connections are usually not valid LAN connections and are not what you are looking for. Supposing Windows does not automatically detect your LAN connection for you, recheck your media (cabling) and unplug then replug the RJ-45 into your computer. This is a rare occurrence and usually at the fault of lower-level hardware (or human error). 16 Making Sure TCP/IP Works Next, you will need to double-click your connection. Another dialogue box should come up shortly. To assure you have properly set up this connection, the dialogue box should read “Connected” and have both many sent and received packets. Now, double-click “Properties.” Once the properties dialogue box shows up, click on the text of “TCP/IP” and press “Properties.” Now, make sure you have set it to “Obtain IP Address Automatically” and to “Obtain DNS Automatically.” Recall back to DHCP Configuration. The DHCP Server on your switch/router will assign your computer an IP rather than your computer declare one for itself in order to reduce the stress on the network and to avoid IP collision, or two or more computers claiming the same IP address. Also, remember that the IP addresses assigned by your router are internal ones and are not known to the outside Internet. 17 Once you have completed all of this, “OK” your way out of the dialogue boxes and now go to Start -> Run and type in the Run field “cmd” in order to open up a command prompt. Once the command prompt has opened, type in “ipconfig /all” If your settings show up right away, you are good to go! You have successfully set up a basic TCP/IP network on Windows XP. Now, you are ready to configure your computer for more, but for now, your computer is a new node on a brand new network. 18 Bonus Connect 2 Computers Directly Using Crossover Cable How do you connect 2 computers sometimes for file or printer sharing? Ha! It's pretty easy! You only need 1 crossover cable and 2 network cards . Plug in network card each to computer and then install network card driver for each computer. Connect the cable to both computers’ network card. Yap.. we have finished the setup. Here comes the network configuration, let’s create a simple network by assigning following network info to each computer's network card: Computer A: IP Address: 10.1.1.1 Subnet mask: 255.255.255.0 Gateway: DNS Servers: Computer B: IP Address: 10.1.1.2 Subnet mask: 255.255.255.0 Gateway: DNS Servers: Since these 2 computers are directly connected, no gateway and DNS servers are needed. 19 Here is step-by-step instructions to assign IP address and other network information in Windows 7 Quick Way to Configure IP Address and Other Network Information in Windows 7 Let me show you how to configure IP address and other network information in Windows 7 here. As you know IP address must be configured on computer in order to communicate with other computers, because this IP address is the standard address understood by computers and other networking devices in networking world. You can configure IP address, subnet mask, gateway and DNS servers manually on computer, but you can also configure computer to obtain IP address and other network information from DHCP server (most of the time is configured on router). Without wasting any more time, let me show you quick way to do it: 1) Go to Start and click on Control Panel. 2) Proceed to click View network status and tasks in Control Panel window. 3) Network and Sharing Center window will appear, then click change adapter settings. 20 4) Network Connections window will appears. Here you can right click on the network adapter (can be wireless adapter or wired Ethernet adapter) that you wish to configure and click Properties. 5) In the Network Connection Properties window, tick on Internet Protocol Version 4 (TCP/IPv4) and click Properties. 21 Note: If your computer sits in IPv6 network, you can select Internet Protocol Version 6 (TCP/IPv6) to configure IPv6 address, but it’s not covered here. Manual IP Assigning If you want to do manual configuration, you can now key in the IP address, Subnet mask, Default gateway and DNS servers. Note: IP address of your computer must be unique. None of the 2 computers in the same network can share same IP address, because it will cause IP address conflict. Note: Default gateway is a router that can route the traffic to the other network or Internet. DNS server is an application server that can translate URL to IP address. Check with your ISP on what 22 DNS servers you should use. If not, you can try this free Opendns or Google DNS servers. 23 IP Assigned by DHCP server If you have DHCP server setup on your router or you have dedicated DHCP server, your computer can be assigned IP address and other network information automatically by selecting Obtain an IP address automatically and Obtain DNS server address automatically. Note: If you have a notebook, and you use static IP at home and the IP assigned by DHCP server at the office, you can make use of alternate configuration to set IP and network information for these 2 different networks. Set Obtain an IP address and DNS automatically on General tab as according to what I specified above, so that the notebook will be assigned IP addresses automatically at the office. After that, click Alternate Configuration tab, select User configured option and key in your home network’s static IP and other network information. By setting this, when there is no IP information assigned due to no DHCP server at home, this alternate configuration will be applied automatically, so 24 that you don’t have to spend time on configuring IP manually every time at home. Windows Vista Configuring IP Address and Other Network Information in Windows Vista In this simple article I will show you on configuring IP address and other network information in Windows Vista. The method is almost the same as Windows XP, but the path to access the setting page is different. Here is detailed instruction on configuring IP address and other network information in Window Vista: 1) Go to Start and right click on Network and then click Properties. 2) Network and Sharing Center window will appear, then click Manage network connections. 25 3) Network Connections window will appears. Here you can right click on the network card that you wish to configure and click Properties. 4) In the Local Area Connection Properties window, tick on Internet Protocol Version 4 (TCP/IPv4) and click Properties. Note: If your computer sits in IPv6 network, you can select Internet Protocol Version 6 (TCP/IPv6) to configure IPv6 address. Here I only show IPv4 configuration. 26 Manual IP Assignment You can now key in the IP address, Subnet mask, Default gateway and DNS servers. Note: IP address of your computer must be unique. None of the 2 computers in the network can share same IP address, it causes IP address conflict. Note: Default gateway is a router that can route the traffic to the other network or internet. DNS server is an application server that can translate URL to IP address. As an example, www.cert.org is URL and it can be translated to 192.88.209.6 by DNS server. Check with your ISP on what DNS servers you should use. 27 IP Assigned by DHCP server If you have DHCP server setup on your router or you have DHCP server, your computer can be assigned IP address automatically by selecting Obtain an IP address automatically and Obtain DNS server address automatically. Note: If you have a notebook, using static IP at home and the IP assigned by DHCP server at the office, you can make use of alternate configuration to set IP and network information for these 2 different networks. 28 Set Obtain an IP address automatically on General tab which is same as what I specified above, so that the notebook will be assigned IP addresses automatically at the office. After that, click Alternate Configuration tab, select User configured option and key in your home network’s static IP information. By setting this, when there is no IP information assigned due to no DHCP server at home, this alternate configuration will be applied automatically, so that you don’t have to spend time on configuring IP manually every time at home. Windows XP How to Set IP Address and Other Network Information in Windows XP IP (Internet Protocol) address is the 4 octets (32-bit) address used to identify your desktop computer, notebook, router, switch or other network devices in your network or Internet. It’s also called as IPv4 (Internet Protocol Version 4). IP address is assigned to network card on your desktop computer or notebook to communicate with other network devices. Each IP Octet can be the value between 0 and 255, but several rules exist for ensuring IP addresses are valid. Examples are 192.168.8.145, 10.11.3.4, etc. 29 Here are step-by-step instructions showing you how to set IP address and other network information: 1) Go to Start and click on Control Panel. 2) Control Panel window will appear. Double click on Network Connections. 3) Network Connections window will appear. Right click correct Local Area Connection by identifying correct network card and click Properties. 4) Select Internet Protocol (TCP/IP). Click on Properties. Manual IP Assigning You can now key in the IP address, Subnet mask, Default gateway and DNS servers. Here is IP logical network Designing Guide. Note: IP address of your computer must be unique. None of the 2 computers in the network can share same IP address, it causes IP address conflict. Note: Default gateway is a router that can route the traffic to the other network or Internet. DNS server is an application server that can translate URL to IP address. As an example, www.cert.org is URL and it can be translated to 192.88.209.6 by DNS server. Check with your ISP on what DNS servers you should use. If not, you can try this free Opendns. 30 IP Assigned by DHCP server If you have DHCP server setup on your router or you have DHCP server in home network, your computer can be assigned IP address automatically by selecting Obtain an IP address automatically and Obtain DNS server address automatically. 31 Note: If you have a notebook, using static IP at home and the IP assigned by DHCP server at the office, you can make use of alternate configuration to set IP and network information for these 2 different network. Set Obtain an IP address automatically on General tab which is same as what I specified above, so that the notebook will be assigned IP addresses automatically at the office. After that, click Alternate Configuration tab, select User configured option and key in your home network’s static IP information. By setting this, when there is no IP information assigned due to no DHCP server at home, this alternate configuration will be applied automatically, so that you don’t have to set IP manually every time at home. 32 After assigning IP address, try to ping the other computer from command prompt, 33 How to differentiate straight and crossover cable What are Straight and Crossover cable Common Ethernet network cable are straight and crossover cable. This Ethernet network cable is made of 4 pair high performance cable that consists twisted pair conductors that used for data transmission. Both end of cable is called RJ45 connector. The cable can be categorized as Cat 5, Cat 5e, Cat 6 UTP cable. Cat 5 UTP cable can support 10/100 Mbps Ethernet network, whereas Cat 5e and Cat 6 UTP cable can support Ethernet network running at 10/100/1000 Mbps. You might heard about Cat 3 UTP cable, it's not popular anymore since it can only support 10 Mbps Ethernet network. Straight and crossover cable can be Cat3, Cat 5, Cat 5e or Cat 6 UTP cable, the only difference is each type will have different wire arrangement in the cable for serving different purposes. Straight Cable You usually use straight cable to connect different type of devices. This type of cable will be used most of the time and can be used to: 1) Connect a computer to a switch/hub's normal port. 2) Connect a computer to a cable/DSL modem's LAN port. 3) Connect a router's WAN port to a cable/DSL modem's LAN port. 4) Connect a router's LAN port to a switch/hub's uplink port. (normally used for expanding network) 5) Connect 2 switches/hubs with one of the switch/hub using an uplink port and the other one using normal port. 34 If you need to check how straight cable looks like, it's easy. Both side (side A and side B) of cable have wire arrangement with same color. Check out different types of straight cable that are available in the market here. Crossover Cable Sometimes you will use crossover cable, it's usually used to connect same type of devices. A crossover cable can be used to: 1) Connect 2 computers directly. 2) Connect a router's LAN port to a switch/hub's normal port. (normally used for expanding network) 3) Connect 2 switches/hubs by using normal port in both switches/hubs. 35 36 In you need to check how crossover cable looks like, both side (side A and side B) of cable have wire arrangement with following different color . Have a look on these crossover cables if you plan to buy one. Lastly, if you still not sure which type of cable to be used sometimes, try both cables and see which works. Note: If there is auto MDI/MDI-X feature support on the switch, hub, network card or other network devices, you don't have to use crossover cable in the situation which I mentioned above. This is because crossover function would be enabled automatically when it's needed. if you need complete ebooks visit

MORE ABOUT PC HARDWARE

MORE ABOUT PC HARDWARE You may think that your PC really doesn’t roar to life until Windows loads. Actually, the PC has a lot of work to do to get to that moment, as you already learned in the section “What Happens When a PC Boots Up.” Then, as you’ll learn in a moment when reading about the role of the operating system, you’ll see that Windows takes over control of your PC once it does load. So what controls the PC from that first push of the power button to the instant the hourglass on the desktop disappears? Something, after all, has to shepherd all those devices like your keyboard, display, and hard drive into service. That something is the BIOS, located on a chip on the motherboard that awakens when power is first supplied to the motherboard after the PC is switched on. Once awake, the BIOS performs an initial inventory of all hardware connected to the PC and manages routines that help bring the hardware online so that the PC bootup process runs smoothly and Windows can indeed load. In the process of Windows loading, Windows looks to the BIOS for information about that hardware and divides it between the PNP vs. non-PNP hardware explained earlier in this chapter. BIOS and How Hardware Connects to the PC When you first install—or reinstall—a troubled device to a PC, the device first communicates with the BIOS, which has the job of fitting it into its master schedule of the other hardware resources. If the BIOS for some reason—the BIOS has been corrupted, the motherboard is damaged, or the hardware is defective, for example—cannot see the device you’ve installed or doesn’t recognize the connection type the device is connected to, the device will not work. In this respect, the BIOS is the first hurdle you have to pass in working with your hardware. Becoming Familiar with Your BIOS Make sure you become familiar with your BIOS, especially the settings you can enable/disable or alter within it, before you get too deeply into a situation that requires you to understand the BIOS. The BIOS can only be accessed by you when the PC is first started. The initial bootup display includes a message stating something like Press to enter Setup. The exact key or combination of keys you need to press depends on the make and model of your PC. Often, this is the Delete key. Once pressed, the system should bring up the BIOS configuration window, sometimes called CMOS Setup. Your available options depend on the make and age of your BIOS, but you should see a menu of categories like these: Standard Settings This category includes date and time settings, drives connected, and basic hardware found. Advanced Settings Advanced settings include whether to look at the floppy drive to see if a boot disk is present before booting off the hard drive, cache options, and memory tests. Bus Settings This category provides configurable options for tweaking performance regarding the hardware installed into the expansion bus slots. Integrated Peripherals This section contains information on whether certain hardware devices and connectors are enabled or disabled, including the USB controller, drive controllers, and the serial and parallel ports. Power Management This section contains options for setting or disabling power management features to reduce the power supplied to certain hardware components (monitor, drives, and so on) when the PC is not in active use. You can use PC information sites such as PC Guide (www.pcguide.com) and PCMechanic (www.pcmechanic.com) to learn more about these BIOS options. Rooting Out the Problem: Troubleshooting Basics A good PC technician is two parts sleuth, one part smart user, and two parts person desperate to get the current problem resolved so he or she can get back to work or play. It’s how much those first three parts can overcome the final two parts that can ensure your success. One of the tools a good sleuth has at his or her disposal is the knowledge of the most likely circumstances surrounding a mystery, based on things like statistical averages and past experience. So a PC sleuth should know that some of the most common causes of PC problems include • Corrupted, incorrect, or bad driver for a device • Incomplete or bad upgrade • Poorly behaved program just installed • Loose or bad cables and connectors • Corrupted program or program installation • A temporary problem that can be resolved by a simple restart of your PC Using this information, a PC detective would • Check and update drivers. • Recheck an upgrade or installation and try to repair it, if applicable. • Check power and cables for looseness or other issues. • Uninstall and reinstall problem programs. • Restart the PC to see if the situation resolves. Rules of the Road Every troubleshooter, experienced or not, has to follow certain basic rules in working with a PC. Here are 10 of the most important rules you need to follow as you work: 1. Work with adequate lighting. 2. Avoid making snap assumptions. 3. Before you proceed, make certain your data is protected. If you can reach your files and folders, copy or back them up first. If you have to troubleshoot to reach that point, do it ASAP. 4. Before assuming a device is broken, check to be sure it’s properly connected and plugged into a viable power source. 5. Always check to be sure connections and cables are secure and in good shape. Lots of crimping or gouging of the cable, for example, means you should replace the cable. 6. If you absolutely don’t know what to do, don’t do anything unless you’re sure you can back out of it again. 7. Never work inside your PC case with the power connected; the PC must be turned off and the power cord removed from the back of the PC. 8. Never work inside your PC case without being properly grounded using something like an anti-static wrist strap. 9. Never think, “If it doesn’t fit, force it.” If something doesn’t fit, it’s usually being installed improperly or is of the wrong connection type. 10. Don’t forget to read the instructions. Some of them may be badly written, but they aren’t optional. The manufacturer’s web site may offer better help. Table 11.1: PC Hardware Wattage Requirements Device Typical Wattage Required to Operate CD drive (48x) 7–30 watts (Depends on the CD formats supported.) CPU 18–50 watts (Depends on the CPU type and age; a Pentium III often takes 20–30 watts, while some Athlons require 40 watts or more.) Fans Variable; a case fan often needs 12 watts. Floppy drive 4–5 watts Hard drive (IDE/ATA) 5–20 watts per drive (Often, the higher the drive RPM, the higher the wattage used.) Memory 10 watts per 128MB (some higher, some lower) Motherboard (bare) 20–35 watts Network adapter 4–5 watts SCSI host adapter 20–30 watts Sound (card) adapter (PCI) 5–20 watts Video adapter (AGP) 18–35 watts Video adapter (PCI) 4–15 watts These are rough estimates; check the technical specifications for your devices, which are usually available in the product documentation. The following are the most common causes for PC overheating: • Blocked intake and exhaust vents • Operating the PC in a very warm environment • Dirty or malfunctioning internal fans • Heavy dust accumulation on internal components • Overcrowding of equipment within the case • Adding several “hot” components without augmenting internal cooling • Overclocking (the process of changing hardware settings to “push” hardware beyond its rated speed/operation) Symptoms of Overheating Overheating can actually cause some rather bizarre and not-easily-explained phenomena. Here are just some of the symptoms you might see with either acute one-time or chronic overheating: • A PC that was operating fine when you first turned it on begins to develop increasing problems. For example, you type one thing but the monitor displays another, opening or saving files to a disk gives you drive errors, or hardware “disappears.” A restart of the PC does little or no good. • You place your hand near an exhaust point, such as at the location of the power supply fan, and notice little or no air being pushed out against your hand. Under ideal conditions, the fan output here isn’t exactly robust, but you should feel a steady flow of warm air. • If you turn the PC on, it appears to start normally and then resets itself after a short period of time, usually the time it takes for the PC to warm up. • You notice parts of the case, especially where drives are located or the side where the motherboard sits, become extremely warm to the touch. • You go inside your system—with power disconnected and properly grounded—and note that components are (or almost are) too hot to touch. • There may be a smell—often a compound of smells related to overheated components, grease, and dust—that may or may not seem like burning. • You receive an on-screen warning about internal temperature. This is a feature with some motherboards and accessories you may add, but not available or enabled on every system. Common Symptoms and Their Culprits When PC performance begins to sag, you can usually feel it, even instinctively. A few of the most frequently noted symptoms are • Prolonged time between the moment you press the power button and the time Windows loads (or reloads) • Sluggish shutdowns • Slowdown in disk operations, including the opening of file screens through Windows Explorer or the Search feature • Programs taking longer than usual to load • Difficulty in changing your focus among different windows open on your desktop There are so many potentially contributing factors to ailing PC performance that they merit a book of their own. Some of the most common issues responsible for slowdowns include • Poor disk maintenance practices • Poor system organization (You don’t watch what is installed or you don’t remove from your hard drive programs you no longer use or data you no longer need to keep.) • Underpowered or overworked PC (not enough disk space, too little memory, and so on) • Viruses (Remember, many viruses annoy more than destroy.) • Poorly configured or missing Windows page file for virtual memory (explained later in this chapter) • Hardware issues, including bad drivers, device conflicts, or failing (but not quite failed) devices • An imbalance in resources (For example, you’re running many background programs by choice, and the balance of processing power is going to the foreground programs such that you have an imbalanced load. Just like your washing machine, Windows works best and makes less noise when you watch what you load and how you load it.) Table 1-1. PC 99 recommended connector color codes Connector Color Connector Color Analog VGA Blue PS/2-compatible keyboard Purple Audio Line-in Light Blue PS/2-compatible mouse Green Audio Line-out Lime Serial Teal/Turquoise Digital monitor/flat panel White Speaker out/subwoofer Orange IEEE 1394 Grey Right-to-left speaker Brown Microphone Pink USB Black MIDI/gameport Gold Video Out Yellow Parallel Burgundy SCSI, LAN, telephone, etc. Not defined Table 1-2. 8/16/32-bit ISA/PCI standard IRQ assignments IRQ Bus type Typically used by 00 none Non-maskable Interrupt (NMI); system timer 01 none Keyboard port 02 none Programmable Interrupt Controller (PIC); cascade to IRQ 09 03 8/16-bit Communications Port 2 (COM2:) 04 8/16-bit Communications Port 1 (COM1:) 05 8/16-bit Sound card; Printer Port (LPT2:) 06 8/16-bit Floppy Disk Controller 07 8/16-bit Printer Port (LPT1:) 08 none System CMOS/real-time clock 09 8/16-bit Redirected from IRQ 02; network interface 10 16-bit Network interface; USB host controller 11 16-bit Video Adapter; SCSI host adapter 12 16-bit PS/2 mouse port 13 none Numeric Data Processor (math co-processor) 14 16-bit Primary IDE interface 15 16-bit Secondary IDE interface Table 23.1: DOS/Windows Common File Extensions File Extension Association .BAK DOS backup file .BAT DOS file housing a sequence of commands .BMP Windows bit-mapped graphics file .CAB Windows 9x cabinet file .COM DOS command program file .DLL Windows dynamic link library file .DOC Text document file (usually Microsoft Word) .EXE DOS executable program .GRP Windows 3x program group file .HTM Hypertext markup language file .ICO Windows 3x icon file .INI DOS Windows initialization file .SYS DOS system driver/hardware configuration file .TMP Temporary file .TXT Text file created by DOS or the Windows text editor .VXD Virtual device driver file Symbol Definition Kb Kilobit — 1,024 bits KB Kilobyte — 1,024 bytes Mb Megabit — 1,048,576 bits MB Megabyte — 1,048,576 bytes Gb Gigabit — 1,073,741,824 bits GB Gigabyte — 1,073,741,824 bytes

SMD Soldering Guide

1 SMD Soldering Guide Basic Electronics Soldering & Desoldering Guide VERY VERY IMPORTANT: This chapters will expose you to the art of soldering eletronic components on a laptop motherboard with pictures and video illustrations, it is therefore critical that you understand this very concept which forms 95% of chip level repairs This written guide will help beginners and novices to obtain effective results when soldering electronic components. If you have little or no experience of using a soldering iron, then EPE (Everyday Practical Electronics magazine) recommends that you practice your soldering technique on some fresh surplus components and clean stripboard (protoboard), before experimenting with a proper constructional project. This will help you to avoid the risk of disappointment when you start to assemble your first prototypes. If you've never soldered before, then read on! Soldering irons Topics in this section include: Voltage Wattage Temperature Control Soldering Stations Anti Static Protection Bits (Tips) Spare Parts Gas-Powered irons The most fundamental skill needed to assemble any electronic project is that of soldering. It takes some practice to make the perfect joint, but, like riding a bicycle, once 2 learned is never forgotten! The idea is simple: to join electrical parts together to form an electrical connection, using a molten mixture of lead and tin (solder*) with a soldering iron. A large range of soldering irons is available - which one is suitable for you depends on your budget and how serious your interest in electronics is. [*Note: the use of lead in solder is now increasingly prohibited in many countries. "Lead free" solder is now statutory instead.] Electronics catalogues often include a selection of well-known brands of soldering iron. Excellent British-made ones include the universally popular Antex, Adcola and Litesold makes. Other popular brands include those made by Weller and Ungar. A very basic mains electric soldering iron can cost from under £5 (US$ 8), but expect a reasonable model to be approximately £10-£12 (US$ 16 - 20) - though it's possible to spend into three figures on a soldering iron "station" if you're really serious! Check some suppliers' catalogues for some typical types. Certain factors you need to bear in mind include:- Voltage: most irons run from the mains at 240V. However, low voltage types (e.g. 12V or 24V) generally form part of a "soldering station" and are designed to be used with a special controller made by the same manufacturer. Wattage: Typically, they may have a power rating of between 15-25 watts or so, which is fine for most work. A higher wattage does not mean that the iron runs hotter - it simply means that there is more power in reserve for coping with larger joints. This also depends partly on the design of the "bit" (the tip of the iron). Consider a higher wattage iron simply as being more "unstoppable" when it comes to heavier-duty work, because it won't cool down so quickly. Temperature Control: the simplest and cheapest types don't have any form of temperature regulation. Simply plug them in and switch them on! Thermal regulation is "designed in" (by physics, not electronics!): they may be described as "thermally balanced" so that they have some degree of temperature "matching" but their output will otherwise not be controlled. Unregulated irons form an ideal general purpose iron for most users, and they generally cope well with printed circuit board soldering and general interwiring. Most of these "miniature" types of iron will be of little use when attempting to solder large joints (e.g. very large terminals or very thick wires) because the component being soldered will "sink" heat away from the tip of the iron, cooling it down too much. (This is where a higher wattage comes in useful.) A proper temperature-controlled iron will be quite a lot more expensive - retailing at say £40 (US$ 60) or more - and will have some form of built-in thermostatic control, to ensure that the temperature of the bit (the tip of the iron) is maintained at a fixed level (within limits). This is desirable especially during more frequent use, since it helps to ensure that the temperature does not "overshoot" in between times, and also guarantees that the output will be relatively stable. Some irons have a bimetallic strip thermostat built into the handle which gives an audible "click" in use: other types use all-electronic controllers, and some may be adjustable using a screwdriver. 3 Yet more expensive still, soldering stations cost from £70 (US$ 115) upwards (the iron may be sold separately, so you can pick the type you prefer), and consist of a complete bench-top control unit into which a special low-voltage soldering iron is plugged. Some versions might have a built-in digital temperature readout, and will have a control knob to enable you to vary the setting. The temperature could be boosted for soldering larger joints, for example, or for using higher melting-point solders (e.g. silver solder). These are designed for the most discerning users, or for continuous production line/ professional use. The best stations have irons which are well balanced, with comfort-grip handles which remain cool all day. A thermocouple will be built into the tip or shaft, which monitors temperature. Anti-static protection: if you're interested in soldering a lot of static-sensitive parts (e.g. CMOS chips or MOSFET transistors), more advanced and expensive soldering iron stations use static-dissipative materials in their construction to ensure that static does not build up on the iron itself. You may see these listed as "ESD safe" (electrostatic discharge proof). The cheapest irons won't necessarily be ESD-safe but never the less will still probably perform perfectly well in most hobby or educational applications, if you take the usual anti-static precautions when handling the components. The tip would need to be well earthed (grounded) in these circumstances. Bits: it's useful to have a small selection of manufacturer's bits (soldering iron tips) available with different diameters or shapes, which can be changed depending on the type of work in hand. You'll probably find that you become accustomed to, and work best with, a particular shape of tip. Often, tips are iron-coated to preserve their life, or they may be bright-plated instead. Copper tips are seldom seen these days. Spare parts: it's nice to know that spare parts may be available, so if the element blows, you don't need to replace the entire iron. This is especially so with expensive irons. Check through some of the larger mail-order catalogues. You will occasionally see gas-powered soldering irons which use butane rather than the mains electrical supply to operate. They have a catalytic element which, once warmed up, continues to glow hot when gas passes over them. Service engineers use them for working on repairs where there may be no power available, or where a joint is tricky to reach with a normal iron, so they are really for occasional "on the spot" use for quick repairs, rather than for mainstream construction or assembly work. One example is the Maplin PG509, given a full review with photographs here. Another technique is the proprietary "Coldheat" battery powered soldering iron that we reviewed here. There are a number of reasons why this should only be used with extreme care (if at all) on electronic circuitboards. A solder gun is a pistol-shaped iron, typically running at 100W or more, and is completely unsuitable for soldering modern electronic components: they're too hot, heavy and unwieldy for micro-electronics use. Plumbing, maybe..! 4 Soldering irons are best used along with a heat-resistant bench-type holder, so that the hot iron can be safely parked in between use. Soldering stations already have this feature, otherwise a separate soldering iron stand is essential, preferably one with a holder for tipcleaning sponges. Now let's look at how to use soldering irons properly, and how to put things right when a joint goes wrong. How to solder Turning to the actual techniques of soldering, firstly it's best to secure the work somehow so that it doesn't move during soldering and affect your accuracy. In the case of a printed circuit board, various holding frames are fairly popular especially with densely populated boards: the idea is to insert all the parts on one side ("stuffing the board"), hold them in place with a special foam pad to prevent them falling out, turn the board over and then snip off the wires with cutters before making the joints. The frame saves an awful lot of turning the board over and over, especially with large boards. Other parts could be held firm in a modeller's small vice, for example. Solder joints may need to possess some degree of mechanical strength in some cases, especially with wires soldered to, say, potentiometer or switch tags, and this means that the wire should be looped through the tag and secured before solder is applied. The down side is that it is more difficult to de-solder the joint (see later) and remove the wire afterwards, if required. Otherwise, in the case of an ordinary circuit board, components' wires are bent to fit through the board, inserted flush against the board's surface, splayed outwards a little so that the part grips the board, and then soldered. In my view - opinions vary - it's generally better to snip the surplus wires leads off first, to make the joint more accessible and avoid applying a mechanical shock to the p.c.b. joint. However, in the case of semiconductors, I often tend to leave the snipping until after the joint has been made, since the excess wire will help to sink away some of the heat from the semiconductor junction. Integrated circuits can either be soldered directly into place if you are confident enough, or better, use a dual-in-line socket to prevent heat damage. The chip can then be swapped out if needed. Parts which become hot in operation (e.g. some resistors), are raised above the board slightly to allow air to circulate. Some components, especially large electrolytic capacitors, may require a mounting clip to be screwed down to the board first, otherwise the part may eventually break off due to vibration. The perfectly soldered joint will be nice and shiny looking, and will prove reliable in service. I would say that: 5  cleanliness  temperature  time  adequate solder coverage are the key factors affecting the quality of the joint. A little effort spent now in soldering the perfect joint may save you - or somebody else - a considerable amount of time in troubleshooting a defective joint in the future. The basic principles are as follows. Really Clean Firstly, and without exception, all parts - including the iron tip itself - must be clean and free from contamination. Solder just will not "take" to dirty parts! Old components or copper board can be notoriously difficult to solder, because of the layer of oxidation which builds up on the surface of the leads. This repels the molten solder and this will soon be evident because the solder will "bead" into globules, going everywhere except where you need it. Dirt is the enemy of a good quality soldered joint! Hence, it is an absolute necessity to ensure that parts are free from grease, oxidation and other contamination. In the case of old resistors or capacitors, for example, where the leads have started to oxidise, use a small hand-held file or perhaps scrape a knife blade or rub a fine emery cloth over them to reveal fresh metal underneath. Stripboard and copper printed circuit board will generally oxidise after a few months, especially if it has been fingerprinted, and the copper strips can be cleaned using an abrasive rubber block, like an aggressive eraser, to reveal fresh shiny copper underneath. Also available is a fibre-glass filament brush, which is used propelling-pencil-like to remove any surface contamination. These tend to produce tiny particles which are highly irritating to skin, so avoid accidental contact with any debris. Afterwards, a wipe with a rag soaked in cleaning solvent will remove most grease marks and fingerprints. After preparing the surfaces, avoid touching the parts afterwards if at all possible. Another side effect of having dirty surfaces is the tendency for people to want to apply more heat in an attempt to "force the solder to take". This will often do more harm than good because it may not be possible to burn off any contaminants anyway, and the component may be overheated. In the case of semiconductors, temperature is quite critical and they may be harmed by applying such excessive heat. Before using the iron to make a joint, it should be "tinned" (coated with solder) by applying a few millimetres of solder, then wiped on a damp sponge preparing it for use: you should always do this immediately with a new bit, anyway. Personally, I always reapply a very small amount of solder again, mainly to improve the thermal contact between the iron and the joint, so that the solder will flow more quickly and easily. It's sometimes better to tin larger parts as well before making the joint itself, but it isn't generally necessary with p.c.b. work. (All EPE printed circuit boards are "roller-tinned" to preserve their quality and to help with soldering.) A worthwhile product is Weller's Tip 6 Tinner & Cleaner, a small 15 gram tinlet of paste onto which you dab a hot iron - the product cleans and tins the iron ready for use. An equivalent is Adcola Tip-Save. Normal electronics grade solder is now "lead free" and typically contains Sn 97 Ag 2.5 Cu 0.5 (i.e. 97% tin, 2.5% silver and 0.5% copper). It already contains cores of "flux" which helps the molten solder to flow more easily over the joint. Flux removes oxides which arise during heating, and is seen as a brown fluid bubbling away on the joint. The use of separate acid flux paste (e.g. as used by plumbers) should NEVER be necessary in normal electronics applications because electronics-grade solder already contains the correct grade of flux! Other solders are available for specialist work, including aluminium and silver-solder. Different solder diameters are produced, too; 20-22 SWG (19-21 AWG) is 0.91-0.71mm diameter and is fine for most work. Choose 18 SWG (16 AWG) for larger joints requiring more solder. Temperature Another step to successful soldering is to ensure that the temperature of all the parts is raised to roughly the same level before applying solder. Imagine, for instance, trying to solder a resistor into place on a printed circuit board: it's far better to heat both the copper p.c.b. and the resistor lead at the same time before applying solder, so that the solder will flow much more readily over the joint. Heating one part but not the other is far less satisfactory joint, so strive to ensure that the iron is in contact with all the components first, before touching the solder to it. The melting point of most solder is in the region of 188°C (370°F) and the iron tip temperature is typically 330-350°C (626°-662°F). The latest lead-free solders typically require a higher temperature. Now is the time Next, the joint should be heated with the bit for just the right amount of time - during which a short length of solder is applied to the joint. Do not use the iron to carry molten solder over to the joint! Excessive time will damage the component and perhaps the circuit board copper foil too! Heat the joint with the tip of the iron, then continue heating whilst applying solder, then remove the iron and allow the joint to cool. This should take only a few seconds, with experience. The heating period depends on the temperature of your iron and size of the joint - and larger parts need more heat than smaller ones - but some parts (semiconductor diodes, transistors and i.c.s), are sensitive to heat and should not be heated for more than a few seconds. Novices sometimes buy a small clip-on heatshunt, which resembles a pair of aluminium tweezers. In the case of, say, a transistor, the shunt is attached to one of the leads near to the transistor's body. Any excess heat then diverts up the heat shunt instead of into the transistor junction, thereby saving the device from over-heating. Beginners find them reassuring until they've gained more experience. Solder Coverage The final key to a successful solder joint is to apply an appropriate amount of solder. Too much solder is an unnecessary waste and may cause short circuits with adjacent joints. 7 Too little and it may not support the component properly, or may not fully form a working joint. How much to apply, only really comes with practice. A few millimetres only, is enough for an "average" p.c.b. joint, (if there is such a thing). Desoldering methods A soldered joint which is improperly made will be electrically "noisy", unreliable and is likely to get worse in time. It may even not have made any electrical connection at all, or could work initially and then cause the equipment to fail at a later date! It can be hard to judge the quality of a solder joint purely by appearances, because you cannot say how the joint actually formed on the inside, but by following the guidelines there is no reason why you should not obtain perfect results. A joint which is poorly formed is often called a "dry joint". Usually it results from dirt or grease preventing the solder from melting onto the parts properly, and is often noticeable because of the tendency of the solder not to "spread" but to form beads or globules instead, perhaps partially. Alternatively, if it seems to take an inordinately long time for the solder to spread, this is another sign of possible dirt and that the joint may potentially be a dry one. There will undoubtedly come a time when you need to remove the solder from a joint: possibly to replace a faulty component or fix a dry joint. The usual way is to use a desoldering pump or vacuum pump which works like a small spring-loaded bicycle pump, only in reverse! (More demanding users using CMOS devices might need a pump which is ESD safe.) A spring-loaded plunger is released at the push of a button and the molten solder is then drawn up into the pump. It may take one or two attempts to clean up a joint this way, but a small desoldering pump is an invaluable tool especially for p.c.b. work. Sometimes, it's effective to actually add more solder and then desolder the whole lot with a pump, if the solder is particularly awkward to remove. Care is needed, though, to ensure that the boards and parts are not damaged by excessive heat; the pumps themselves have a P.T.F.E. nozzle which is heat proof but may need replacing occasionally. An excellent alternative to a pump is to use desoldering braid, including the famous American "Soder-Wick" (sic) or Adcola "TISA-Wick" which are packaged in small dispenser reels. This product is a specially treated fine copper braid which draws molten 8 solder up into the braid where it solidifies. The best way is to use the tip of the hot iron to press a short length of braid down onto the joint to be de-soldered. The iron will subsequently melt the solder, which will be drawn up into the braid. Take extreme care to ensure that you don't allow the solder to cool with the braid adhering to the work, or you run the risk of damaging p.c.b. copper tracks when you attempt to pull the braid off the joint. See my photo gallery for more details. I recommend buying a small reel of de-soldering braid, especially for larger or difficult joints which would take several attempts with a pump. It is surprisingly effective, especially on difficult joints where a desoldering pump may prove a struggle. Here's a summary of how to make the perfect solder joint. 1. All parts must be clean and free from dirt and grease. 2. Try to secure the work firmly. 3. "Tin" the iron tip with a small amount of solder. Do this immediately, with new tips being used for the first time. 4. Clean the tip of the hot soldering iron on a damp sponge. 5. Many people then add a tiny amount of fresh solder to the cleansed tip. 6. Heat all parts of the joint with the iron for under a second or so. 7. Continue heating, then apply sufficient solder only, to form an adequate joint. 8. Remove and return the iron safely to its stand. 9. It only takes two or three seconds at most, to solder the average p.c.b. joint. 10. Do not move parts until the solder has cooled. Troubleshooting Guide  Solder won't "take" - grease or dirt present - desolder and clean up the parts. Or, material may not be suitable for soldering with lead/tin solder (eg aluminium).  Joint is crystalline or grainy-looking - has been moved before being allowed to cool, or joint was not heated adequately - too small an iron/ too large a joint.  Solder joint forms a "spike" - probably overheated, burning away the flux. First Aid If you are unlucky enough to receive burns which require treatment, here's what to do :- 1. Immediately cool the affected area with cold running water for several minutes. 2. Remove any rings etc. before swelling starts. 3. Apply a sterile dressing to protect against infection. 4. Do not apply lotions, ointments etc., nor prick any blisters which form later. 5. Seek professional medical advice where necessary. 9 First a few safety precautions:  Never touch the element or tip of the soldering iron. They are very hot (about 400°C) and will give you a nasty burn.  Take great care to avoid touching the mains flex with the tip of the iron. The iron should have a heatproof flex for extra protection. An ordinary plastic flex will melt immediately if touched by a hot iron and there is a serious risk of burns and electric shock.  Always return the soldering iron to its stand when not in use. Never put it down on your workbench, even for a moment!  Work in a well-ventilated area. The smoke formed as you melt solder is mostly from the flux and quite irritating. Avoid breathing it by keeping you head to the side of, not above, your work.  Wash your hands after using solder. Solder contains lead which is a poisonous metal. If you are unlucky (or careless!) enough to burn yourself please read the First Aid section. Preparing the soldering iron:  Place the soldering iron in its stand and plug in. The iron will take a few minutes to reach its operating temperature of about 400°C.  Dampen the sponge in the stand. The best way to do this is to lift it out the stand and hold it under a cold tap for a moment, then squeeze to remove excess water. It should be damp, not dripping wet.  Wait a few minutes for the soldering iron to warm up. You can check if it is ready by trying to melt a little solder on the tip.  Wipe the tip of the iron on the damp sponge. This will clean the tip.  Melt a little solder on the tip of the iron. This is called 'tinning' and it will help the heat to flow from the iron's tip to the joint. It only needs to be done when you plug in the iron, and occasionally while soldering if you need to wipe the tip clean on the sponge. You are now ready to start soldering: 10  Hold the soldering iron like a pen, near the base of the handle. Imagine you are going to write your name! Remember to never touch the hot element or tip.  Touch the soldering iron onto the joint to be made. Make sure it touches both the component lead and the track. Hold the tip there for a few seconds and...  Feed a little solder onto the joint. It should flow smoothly onto the lead and track to form a volcano shape as shown in the diagram. Apply the solder to the joint, not the iron.  Remove the solder, then the iron, while keeping the joint still. Allow the joint a few seconds to cool before you move the circuit board.  Inspect the joint closely. It should look shiny and have a 'volcano' shape. If not, you will need to reheat it and feed in a little more solder. This time ensure that both the lead and track are heated fully before applying solder. If you are unlucky (or careless!) enough to burn yourself please read the First Aid section. Using a heat sink Some components, such as transistors, can be damaged by heat when soldering so if you are not an expert it is wise to use a heat sink clipped to the lead between the joint and the component body. You can buy a special tool, but a standard crocodile clip works just as well and is cheaper. Soldering Advice for Components It is very tempting to start soldering components onto the circuit board straight away, but please take time to identify all the parts first. You are much less likely to make a mistake if you do this! Crocodile clip Rapid Electronics 11 1. Stick all the components onto a sheet of paper using sticky tape. 2. Identify each component and write its name or value beside it. 3. Add the code (R1, R2, C1 etc.) if necessary. Many projects from books and magazines label the components with codes (R1, R2, C1, D1 etc.) and you should use the project's parts list to find these codes if they are given. 4. Resistor values can be found using the resistor colour code 5. Capacitor values can be difficult to find because there are many types with different labelling systems! Some components require special care when soldering. Many must be placed the correct way round and a few are easily damaged by the heat from soldering. Appropriate warnings are given in the table below, together with other advice which may be useful when soldering. For most projects it is best to put the components onto the board in the order given below: Components Pictures Reminders and Warnings 1 IC Holders (DIL sockets) Connect the correct way round by making sure the notch is at the correct end. Do NOT put the ICs (chips) in yet. 2 Resistors No special precautions are needed with resistors. 3 Small value capacitors (usually less than 1μF) These may be connected either way round. Take care with polystyrene capacitors because they are easily damaged by heat. 4 Electrolytic capacitors (1μF and greater) Connect the correct way round. They will be marked with a + or - near one lead. 5 Diodes Connect the correct way round. Take care with germanium diodes (e.g. OA91) because they are easily damaged by heat. 6 LEDs Connect the correct way round. The diagram may be labelled a or + for anode and k or - 12 for cathode; yes, it really is k, not c, for cathode! The cathode is the short lead and there may be a slight flat on the body of round LEDs. 7 Transistors Connect the correct way round. Transistors have 3 'legs' (leads) so extra care is needed to ensure the connections are correct. Easily damaged by heat. 8 Wire Links between points on the circuit board. single core wire Use single core wire, this is one solid wire which is plastic-coated. If there is no danger of touching other parts you can use tinned copper wire, this has no plastic coating and looks just like solder but it is stiffer. 9 Battery clips, buzzers and other parts with their own wires Connect the correct way round. 10 Wires to parts off the circuit board, including switches, relays, variable resistors and loudspeakers. stranded wire You should use stranded wire which is flexible and plasticcoated. Do not use single core wire because this will break when it is repeatedly flexed. 11 ICs (chips) Connect the correct way round. Many ICs are static sensitive. Leave ICs in their antistatic packaging until you need them, then earth your hands by touching a metal water pipe or window frame before touching the ICs. Carefully insert ICs in their holders: make sure all the pins are lined up with the socket then push down firmly with your thumb. 13 What is solder? Solder is an alloy (mixture) of tin and lead, typically 60% tin and 40% lead. It melts at a temperature of about 200°C. Coating a surface with solder is called 'tinning' because of the tin content of solder. Lead is poisonous and you should always wash your hands after using solder. Solder for electronics use contains tiny cores of flux, like the wires inside a mains flex. The flux is corrosive, like an acid, and it cleans the metal surfaces as the solder melts. This is why you must melt the solder actually on the joint, not on the iron tip. Without flux most joints would fail because metals quickly oxidise and the solder itself will not flow properly onto a dirty, oxidised, metal surface. The best size of solder for electronics is 22swg (swg = standard wire gauge). Desoldering At some stage you will probably need to desolder a joint to remove or re-position a wire or component. There are two ways to remove the solder: 1. With a desoldering pump (solder sucker)  Set the pump by pushing the spring-loaded plunger down until it locks.  Apply both the pump nozzle and the tip of your soldering iron to the joint.  Wait a second or two for the solder to melt.  Then press the button on the pump to release the plunger and suck the molten solder into the tool.  Repeat if necessary to remove as much solder as possible. Reels of solder Rapid Electronics Using a desoldering pump (solder sucker) 14  The pump will need emptying occasionally by unscrewing the nozzle. 2. With solder remover wick (copper braid)  Apply both the end of the wick and the tip of your soldering iron to the joint.  As the solder melts most of it will flow onto the wick, away from the joint.  Remove the wick first, then the soldering iron.  Cut off and discard the end of the wick coated with solder. After removing most of the solder from the joint(s) you may be able to remove the wire or component lead straight away (allow a few seconds for it to cool). If the joint will not come apart easily apply your soldering iron to melt the remaining traces of solder at the same time as pulling the joint apart, taking care to avoid burning yourself. First Aid for Burns Most burns from soldering are likely to be minor and treatment is simple:  Immediately cool the affected area under gently running cold water. Keep the burn in the cold water for at least 5 minutes (15 minutes is recommended). If ice is readily available this can be helpful too, but do not delay the initial cooling with cold water.  Do not apply any creams or ointments. The burn will heal better without them. A dry dressing, such as a clean handkerchief, may be applied if you wish to protect the area from dirt.  Seek medical attention if the burn covers an area bigger than your hand. To reduce the risk of burns:  Always return your soldering iron to its stand immediately after use.  Allow joints and components a minute or so to cool down before you touch them.  Never touch the element or tip of a soldering iron unless you are certain it is cold. Solder remover wick 15 SMD Soldering Purpose The purpose of this guide is to introduce SMD (Surface Mount Device) hand soldering. The guide is organized into different methods. Each method is used specifically for a group of SMD components. A simplified list is included with each method to identify which types of SMD components are for the appropriate method. SMD Hand Soldering Methods  Method 1 - Pin by pin Used for : two pin components (0805 caps & res), pitches >= 0.0315" in Small Outline Package, (T)QFP and SOT (Mini 3P).  Method 2 - Flood and suck Used for : pitches <= 0.0315" in Small Outline Package and (T)QFP  Method 3 - Solder paste Used for BGA, MLF / MLA packages; where the pins are underneath the part and inaccessible.  Desoldering SMD Special methods for desoldering without the need for special soldering iron tips. Method 1 - Pin by pin Used for : Diodes, Capacitors and Resistors in sizes like 0603, 0805, 1206, 1210, 1812, 1825, 3216, 3528, 6032, and 7343. Small Outline Packages and QFP with pitches >= 0.0315". Like SO.050" and SO.80mm (0.0315") SOT packages like SOT223, SOT23, SOT143, SOT89, Mini-5P, and Mini-6P. 0805 Capacitor example : 16 Step 1 Place a small amount of solder on one of the two pads. Aprox. 0.5mm in height. Step 2 Grab the 805 part with very fine tweezers. Bring the part overtop of the pads, slight to one side so that the part can sit flat against the PCB. Heat the pad already with solder and slide the part onto the pad so that it is centered between the pads. Remove heat. Step 3 Put a small force down on the part and reheat the one pad to guarantee that the parts is flat against the PCB. Step 4 Solder the other side of the part. The solderings should not look like "round ball" on either side of the parts. If this is the cast, there is too much solder being appied to the joint. A properly soldered joint should have a curved line from the end of the pad to the top of the part as shown in the pictures. 17 Small Outline Package - SO.050 example : Step 1 Place a small amount of solder on one of the conner pads. Aprox. 0.5mm in height. Step 2 Grab the 14 pin SOP part with very fine tweezers. Bring the part overtop of the pads, sit the part on top of the pads. Heat the pad with solder and adjust the part so that it lines up with the pads. Besure the part is flat and aligned, then remove the heat. Step 3 Now solder the rest of the pins, oneat- a-time. Use a chise tpye tip (1/32" wide). Contact the pin and pad at the same time with the conrner of the tip. Do not use the end of the tip or solder will flow from pin to pin. Start with the pin at the adjacent corner to the pin already started. 18 SOT23 example : Step 1 Place a small amount of solder on one of the three pads. Aprox. 0.5mm in height. Step 2 Grab the SOT23 part with very fine tweezers. Bring the part overtop of the pads, slight to one side so that the part can sit flat against the PCB. Heat the pad already with solder and slide the part onto the pad so that it is centered between the three pads. Remove heat. Step 3 Put a small force down on the part and reheat the one pad to guarantee that the parts is flat against the PCB. Step 4 Now solder the other two pins, one-at-atime. Use a chise tpye tip (1/32" wide). Contact the pin and pad at the same time with the conrner of the tip. Do not use the end of the tip or solder will flow from pin to pin. Method 2 - Flood and suck 19 Used for : Small Outline packages and (T)QFP with pitches <= 0.0315". Like SO.025", SO.80mm (0.0315"), SO.65mm (0.0256"), SO.50mm, SO.40mm, and SO.30mm. Small Outline Package - SO.65mm example : Step 1 Place a small amount of solder on one of the conner pads. Aprox. 0.5mm in height. Step 2 Grab the 8 pin SOP part with very fine tweezers. Bring the part overtop of the pads, sit the part on top of the pads. Heat the pad with solder and adjust the part so that it lines up with the pads. Besure the part is flat and aligned, then remove the heat. Step 3 Now flood the opposite row of pins with solder so that there is one continuous flow across the pins as shown. Continue by flooding the other row of pins. Try to keep the solder across the pins as even as possible. 20 Step 4 Using the iron, (or a heated sucker) heat one end of the pins until the solder is melted 2-3 pins in length from the end. Quickly remove the iron and using a solder sucker, suck the excess solder from between the pins. Heat the solder on the next 2-3 pins and do the same until the other end is reached. Do the same on the other side of the chip. Finally inspect the pins to check if any solder is left between them. If there is, re-apply solder between the pins and re-suck. This method works because sucking only removes the solder between the pins and not the solder between the pad and pin. (Thin) Quad Flat Package - SO.80mm example : Step 1 Place a small amount of solder on one of the conner pads. Aprox. 0.5mm in height. 21 Step 2 Grab the 32 pin TQFP part with very fine tweezers. Bring the part overtop of the pads, sit the part on top of the pads. Heat the pad with solder and adjust the part so that it lines up with the pads. Besure the part is flat and aligned on all four sides, then remove the heat. Step 3 Now flood the opposite row of pins with solder so that there is one continuous flow across the pins as shown. Continue by flooding the other three rows of pins. Try to keep the solder across the pins as even as possible. Step 4 Using the iron, (or a heated sucker) heat an end of a row until the solder is melted 2-3 pins in length from the end. Quickly remove the iron and using a solder sucker, suck the excess solder from between the pins. Heat the solder on the next 2-3 pins and do the same until the other end is reached. Do the same on the other three sides of the chip. Finally inspect the pins to check if any solder is left between them. If there is, re-apply solder between 22 the pins and re-suck. This method works because sucking only removes the solder between the pins and not the solder between the pad and pin. Method 3 - Solder paste Used for : Used for BGA, MLF / MLA packages; where the pins are underneath the part and inaccessible. Example : To use this method you will need a head gun or a PCB oven. The following instructions are for a heat gun only. Mount the circuit board in a vise that will not burn when heated. It is recommended that the BGA, MLF / MLA parts be soldered to the PCB first in order not to disturb the soldering of the other regular components. If this is not possible then tin foil can be used to shield the regular components. Step 1 Set the part on the board and line it up as it would be soldered. Take note and or mark the PCB so that you will be able to correctly place the part when heating. Step 2 Spread a thin layer of solder paste across the PCB on the pad area for the BGA, MLF / MLA part. The thickness of the solder paste should be thin enough so that the PCB and pads should be semi-visible. The amount is learned by trail and error and experience. 23 Step 3 Plac e the BG A, MLF / ML A part on the PCB and align. Use needle-nose pliers to hold the part in place while heating. Make sure the pliers are not bare metal or they will get too hot to handle when heating. Using the heat gun, apply heat to the part by holding the heat gun 8cm ( 3") away from the board. Step 4 Keep heating until the solder paste has melted into solder all the way around the part. (Should take 20 - 40 seconds) Be sure that the part is aligned and remove the heat. Blow on the part to harden the solder. Inspect around the edges of the part for solder bridges from pad to pad. If there are bridges you will need to reheat the part, remove it, suck the solder from the pads and the part, and repeat the procedure with less solder paste. Desoldering SMD De-soldering SMD components without special soldering iron tips involves creativity. In most cases the SMD component is destroyed. Try to find the proper tip / tool to de-solder before trying the following examples. 24 0805 Capacitor / Resistor de-soldering : Two pin SMD component, such as a 0805 chip capacitor or resistor, is the easiest to de-solder with a regular soldering iron tip. Simply heat one side until the solder is melted, then quickly move to the other side until the solder is melted. Keep alternating between sides. This will build up heat on each side and the part will slide off the pads in 5 - 10 seconds. Small Outline Package - SO.050 example : Step 1 Flood the each row of pins with solder so that there is one continuous flow across the pins as shown. Try to keep the solder across the pins as even as possible. Get a small screwdriver ready to insert under the part. Step 2 Heat one side and move the iron back and forth until the whole row of pins is melted. Insert the screwdriver under that side and pry up until the pins are off the PCB and out of the solder. Step 3 Suck any extra solder that is left between the pads and the part. 25 Step 4 Grip the part with needle-nose pliers. Heat the other side in the same manner and when the whole row is melted remove the part. Step 5 Suck the solder off the pads ready for the new part. BGA, MLF / MLA de-soldering : Cover the PCB in tin foil except for the BGA, MLF / MLA part and the area around it. Heat the part / PCB 8cm ( 3") away with a heat gun. Try heating both the top and bottom side of the PCB. Keep side pressure on the part with fine point needle-node pliers so it will slide off when the solder melts. Surface Mount Soldering Tutorials It's Not That Bad! More and more ICs come in surface mount packages only these days. And I can't tell you how many times I've heard someone say 'Well I can't solder that because it's SMD'. They're wrong! You can solder anything. That's right, anything from your own dorm-cellroom. 26 That's 0.5mm from pin to pin! 50 pin connector for the GM862. You too can solder this! This tutorial will show you just how to solder crazy things like this connector, leadless ICs, etc. There are a very few tools that are required and a handful that are recommended but you'll be able to solder:  SOT23  TQFP  QFN  Even BGA!  And all the others The tools you absolutely must have: 1. $50+ soldering iron 2. Solder wick 3. Solder (leaded is always easier to work with, but here at SFE we use lead-free) That's it. That's all you need. But how can this be? The process of soldering very tight pitch components or even the larger SMD 1206 components just takes practice, a good iron, and some solder wick. Here is a list of tools I recommend: 1. Wire wrap wire (for 'jumper' wire fixes) 27 2. Wire strippers (adjustable down to 30AWG) 3. Hemostatstweezers will also work) 4. Hot-air rework station ($200 will do it) 5. Monocle (I haven't used one, but others have recommended it to me) 6. Scalpel>green wire fixes) Getting chip X onto board Y First, start by getting some SMD device you'd like to solder. 0603 sized components are easy with a little practice. SOT23 packages are relatively large and are common with voltage regulators. SOIC packages are also a really good place to start as well because the pitch is large and the connections are easy to inspect. 28 Here is the board we are going to demo on. It's a very simple 3.3V Lassen iQ GPS serial to RS232 serial breakout board. We will show how to solder the MAX3232 SOIC 16 IC. A shiny tip is a happy tip. No really. ALWAYS clean your tip. Every time you pull the iron out of the holding stand, swipe it quick on the WET sponge. Get off your ass and wet the sponge before you start. If you don't the iron won't heat correctly and the tip will be toast in a day. A small solder tip is recommended but not required. The important thing about your iron is not getting some microscopic tip, but how evenly the heating is. A soldering iron that does not have a temperature control is not acceptable. That $10 iron that you got in your freshman engineering kit is completely worthless. However, you do not need to spend more than ~$80 for a good iron these days. I touched a $500 Metcal once, but they're really overkill for 99% of soldering. Get a good, variable temperature iron from anyone who will also sell you replacement tips. Tips wear out, and you'll be really mad if you've got a perfectly good iron but no where to get a $10 replacement tip. 29 There is no magic here. Add solder to the first pad on the footprint making it dome a bit. 30 Now take your package with hemostats in your off-hand. Heat the domed pad with the soldering iron, liquefying the solder on that one pad. 31 Slide the component into place and you heat the domed pad. You'll need to orient the package so that the other pins line up with their respective pads. 32 Here's my first attempt at soldering. I haven't soldered in about a year so I'm a bit rusty. I accidentally domed two pads. When I tacked the chip down, I didn't seat it all the way. Make sure the IC and as flat against the PCB as possible. This will help prevent open disconnects (nearly as bad as a jumper and more difficult to detect). 33 This is the second attempt, IC is flat against the PCB, but now you see the theta is tweaked a bit. Could you solder the IC successfully with this placement? Yes, of course. But as the packages get larger and the pin counts go up, your alignment has to improve as well. Do the best you can with 2 to 3 heat-reheat alignments. 34 Nice and straight. Once the package is aligned, remove the soldering iron from the pad holding the component still (applying a little downward pressure helps). If the pad solidifies and the package alignment is wonky, just re-heat the pad, re-align, hold still, and remove the iron. The initial heat-slide-align process takes a fraction of a second with a little practice. Do note: heating and reheating pads stresses them. It's totally normal for a beginner to 'lift' a pad on your first or second soldering project. 'Lifting' a pad is bad thing. It occurs because the exposed metal surface pulls away from the FR4 PCB material underneath (also called delaminating). Basically the pad and trace are toast, but you can always green wire from the pin to a local via or same-net pin. More on that later. 35 Okay, so once you've got the component soldered to the single pad and aligned, you can then solder to all the other pins. Start on the opposite side of the package away from your anchoring pad. If you start soldering from the anchor pin, you run the risk of reheating the pad and the component will slide around or stick to your iron tip. Tip: I usually like to have a small puddle of solder on the tip before I start soldering so that the heat transfers easily from the point of the tip to the pin/pad you are soldering to. 36 Once you've added solder to a few pins, you'll probably notice the solder can fill in between pins. This is ok. Solder that is connecting two (or more) pins together is called a jumper. Most of the time, this is bad and can cause problems. To remove solder between pins, you can use solder wick. Solder wick is composed of small copper strands braided together with some chemical additives that have been formulated and manufactured in such a way to attract the solder. Basically, you're playing with surface tension. With a little practice you can take a ball of solder on the end of your iron and run up and down an IC without ever creating a jumper - using only the surface tension of the solder ball and the incoming solder/flux to move things where they really should be. 37 Since this is nearly impossible for, well, everyone, companies have created solder wick. We like size #2. We buy it in 50' rolls but we also use it like it's Kleenex so 25' should be sufficient for multiple small projects of your own. 38 If you've never played with solder wick before, take the end of your iron and add some solder to the tip - get a good blob. Now take the tip and touch it to the solder wick. After a few seconds, the solder wick will heat up and the solder will migrate from the tip to the wick, spreading quickly - hence 'wicking' away the solder. Solder wick can't be re-used to my knowledge. Once the wick turns silver, you cut off the offending bit and throw it away. Well, try anyway. I usually cut off a 1" hardened piece that goes skittering off behind my desk or onto the carpet. Once you start using solder wick, you'll find bits hidden all around for years to come... But you've got to have it! 39 Now let's see what wick can do for us. If you're Mr. Fancy Pants and don't already have a jumper on your IC, make one - jumper two pins together. For the humans in the group that already have a few jumpers, take the end of wick in your bad hand. You'll want to hold 2-3 inches back from the operation because copper loves to transmit heat! I like to use clean, virgin wick so cut off anything that's already been used. Clean your iron tip and add just a smidgen of solder to the end of your tip (this will aid in heat transfer between the parts). 40 Place the wick length-wise over the two jumpered pins and push the wick down with the side of the iron-tip. Quick note: the very tip of the iron (such as the last 1/10th of the iron shown above) is not as useful as the length of the shiny area. Whenever possible, use the side of the tip rather than the point. You'll find that it is much easier to use and transmit heat with. 41 After a split second, the wick should come up to temperature and the solder on the iron and the solder in the jumper should wick into the copper braid! Now, keeping the iron touching the wick, move the wick away from the part. This entire process should take 1, maybe 2 seconds. Don't get crazy with the heating and re-heating or else you'll stress the pad and the IC. If you're just starting out, you'll probably pull the iron away first. Guess what happens? The wick solders itself to the pins. Just be cool. You've got a very strong metal to metal weld. If you go pulling on the wick you'll tear all sorts of things apart. Instead of pulling like a mad-man, add a bit of solder to your iron tip, apply the tip to the wick, and you'll see everything become molten again. Now remove the iron and wick together and you'll be ok! But wait! When I wick away solder, won't that remove solder that connects the pin to the pad? Effectively removing the good connection? No actually. Back to the surface tension thing, solder wick is not strong enough to sneak solder out from under a pin and pad, only from solder that is floating without a pad to adhere to. This wicking process removes only solder jumpers or bad solder. Good solder connections are left in place. Practice practice practice. It's not hard, it just gets easier with time. Some fun tricks: 1) If you've got a jumper or part with solder hiding in a hard place to reach, add more 42 solder! Adding solder to a jumper causes more flux to be added which helps heat flow. If you've got a bit of solder in a hard to reach spot, adding molten solder can be the microscopic hand that sneaks in, heats up the problem bit, and then you've got a much larger bit that can be wicked away. 2) Smash and grab. If you've got a large number of pins to solder on a tight pitch SMD part (think 50-pin molex connector for the GM862), don't fret. Follow the same steps of adding a dome to the anchor pad, lining up and tacking the anchor pin. Now instead of trying to solder each pin, add solder and heat to groups of pins. Don't worry about jumpers, concentrate on getting proper solder on each pin/pad interface. If you don't properly heat each junction, cold joints and intermittent connections may occur later! 43 Once you've got the entire thing sufficiently jumpered, you go back with wick and carefully wick the extra solder away. 44 No microscope, no special tools required! That's it! No magic tricks. Just a good iron, solder wick, and some practice. But what do you do when things get really screwed up? Continue on SMD Soldering Guide Part II