BROUGHT ABOUT BY DIVINE.O FABIAN (C) 2010 www.easywebsiteng.net NOT E THAT YOU CANNOT GIVE OUT THIS BOOK FREE AND YOU HAVE NO RIGHT TO RESELL IT. COPYRIGHT @ ALLRIGHT RESERVE WARNING! THIS MATERIAL IS A COPYRIGHTED MATERIAL AND NO PART OF THIS BOOK MAY BE PRODUCE OR TRANSMITED IN ANY FORM WHATSOEVER, ELECTRONICAL, PHOTOCOPING OR ANY OTHER FORM OF EXTRATION WITHOUT EXPRESSION IN WRITING AND THE PERMISION FROM THE OWNER. DISCLAIMER We will not be responsible for damage to equipment, your ego, blown parts, county wide power outages, spontaneously generated mini (or larger) black holes, planetary disruptions, or personal injury that may result from the use of this material. DEDICATION I DEDICATE THIS BOOK TO GOD ALMIGHTY WHO IS THE FOUNTAIN OF ALL WISDOM AND CUSTADIAN OF ALL UNDERSTANDING AND TO MY DEAREST WIFE IJEOMA AND MY DAUGHTER ADAEZE FOR THEIR LOVERLY SUPPORT. TABLE OF CONTENT • SAFTY GUIDE TO ELECTRONICS • UNDERSTANDING ANALOGUE & DIGITAL MULTIMETER • IDENTIFICATION OF VARIOUS COMPONENTS • BASIC ELECTRONIC COMPONENTS, SYMBOLS AND APPERERANCES • HOW TO TEST AC/DC VOLTAGES • HOW TO PERFORM A CURRENT TEST • CONTINUITY TEST • TESTING ELECTRONIC COMPONENTS: o FUSE o RESISTORS o LAMP o RELAYS o TRANSISTORS o CAPACITORS o INTEGRATED CIRCUITS o TRANSFORMERS o COIL/INDUCTORS o LED o THERMISTOR o BUZZER o LOUDSPEAKERS o TRANSDUCERS o VARISITOR o EEPROM o SWITHCHES o CRYSTALS o TRIAC o CERAMIC DISK CAPACITOR o DIODE o OPTOISOLATOR o SCR o RECTIFIERS o DC MOTORS • LOW VOLTAGE SUPPLY • HIGH VOLTAGE SUPPY • CIRCUIT SYMBOLS & DESIGN • UNDERSTANDING YOUR MULTIMETER • HOW TO IDENTIFY ORIGINAL GENUE PARTS • TROUBLESHOOTING COMPONENTS BY PHYSICAL BEHAVIOUR-CASE STUDY IS POWER PACK • CONCLUSION SAFETY FIRST When your are working with any electronic device, you must bear it in mind that your safety is paramount. So you must take necessary precaution before venturing into any work or repairs. Electricity must be handled properly and carefully, if not injury or serious shock can result. Below are some of the precautions that must carefully stand against. ELECTRIC SHOCK To avoid electric shock, you must always unplug the device you want to work on before you start. If you are to run any test while the device must on, just be very careful and run the test, and wear a rubber cover in your hand. Also work with on hand while the other is in the pocket. Always use plastic head tools and screw driver. Never work once you are tired. This is a rule you must obey. To read about others logon to www.easywebsiteng.net/books read about other such as discharging smps, right way to discharge cathode ray tube, capacitors, etc You will see some of this type of picture in this book, it is picture illustrated. BEFORE YOU CONTINUE This is the volume 1 of the book “testing electronic components” and to get the complete volumes, you must go to internet and register you copy by following the link www.easywebsiteng.net/register and automatically a message will be sent to you. To see other books by the same author follow this link www.easywebsiteng.net/books Other books by topics 1. LAPTOP MASTER PASSWORD UNMASKED 2. 18 SECRETS IN ADVANCE LAPTOP REPAIRING 3. TROUBLESHOOTING LAPTOP WITH A FLOWCHART 4. HACKING LAPTOP BATTERY 5. SHARP COPIER REPAIR GUIDE 6. ADVANCE APPROACH TO ELECTRONIC REPAIR 7. ONLINE BUSINESS REVEALED FOR NIGERIANS 8. A-Z NETWORKING FOR ALL ONLINE BUSINESS E-BOOKS E-TRAINING SOFTWARES CALL US OR SEND US MAIL TO info@easywebsiteng.net or onyiifabino@ymail.com We will not fail and will serve free. Note your registration is important in receiving free updates. Thanks for co-operation. SAFETY GUIDE IN REPAIRING ELECTRONIC A Guide to Electronics Repair You can either take your electronics to a professional technician or you can do it yourself, which is called do-it-yourself or DIY repairs. Before doing any do-it-yourself repairs, there are several things to consider. One of them is whether the product has a warranty because once you have opened up the device the warranty becomes void. You should consider your skills level - this way, you will avoid electrocution and causing further damage to the device. You should consider how much free time you have. Invest in the appropriate tools before doing repairs. If you plan to do electronics repair for all your devices, you should consider taking a course. Although the internet is convenient, cheap and anonymous, you will be able to do DIY electronics repairs if you have hands-one experience. With an electronics repair course, there is less likelihood for electric shock and causing more damage to the device. With this course, you can do repairs for others for cash and you can even start a career as a home-based technician. There are many electronic devises and it is important that as you search for an electronics repair course, to go for a course that covers whatever you are interested in repairing. One thing you will learn as part of your electronics repairs course is de-soldering and soldering. You will lean to interpret schematics and this will help you as you analyze electric circuits. You will also need an understanding of circuit theory. You will be able to reduce the noise in transformers, to replace components that are damaged, to locate and replace components that make your fuses blow, and you will be able to locate and replace bad connections. Circuits have markings that are hard to understand without prior training in electronics and an electronics repair course will teach you what these markings mean and the lingo used in user's manuals. Safety is one of the most important considerations when dealing with electronic devices and you will need to protect yourself from electrocution. To do this, disconnect the power to eliminate the risk of electric shock and electric fires. After repairing the device, replace the back cover before testing to avoid electrocution. Use insulated materials to avoid shorts after removing circuit boards and wear protective gear such as safety goggles and gloves where necessary. Remember to Flip the Switch Always, always, always remember to turn the power off before servicing anything. This should always be your first step. Do not even open the device unless the power is turned off. Many computers have a number of lights inside that serve certain functions so check to see that no lights are on. If any are still on then the power is probably not completely off. Unplug for Extra Safety As a second precaution, it is wise to unplug the devices from the wall or power strip. If there was any doubt as to whether the device was off before, it's settled now. Avoid Smoke and Smells See smoke coming from the power supply or inside the case or smell a burning or solder scent? If so: 1. Stop what you're doing immediately. 2. Unplug the computer from the wall. 3. Allow the device to cool or discharge unplugged for at least 5 minutes. Finally, if you know which device was generating the smoke or smell, remove and replace it as soon as you can. Don't try to repair a device that's been damaged to this extent, especially if it's a power supply. Remove Hand Jewelry An easy way to get electrocuted is to work around a high voltage device like a power supply with metal rings, watches, or bracelets on. Remove anything conductive from your hands before working inside your computer, especially if you're doing something like testing your power supply. Avoid Capacitors Capacitors are miniature electronic components contained in many of the parts inside a PC. Capacitors can store electric charge for a short while after the power is turned off so it's a wise decision to wait a few minutes after pulling the plug before working on your PC. Never Service the Non-Serviceable When you come across labels that say "No serviceable components inside" don't take it as a challenge or even a suggestion. This is a serious statement. IDENTIFICATION OF ELECTRONIC COMPONENTS BASIC ELECTRONIC COMPONENTS, SYMBOLS AND APPERERANCES There are a large number of symbols which represent an equally large range of electronic components. It is important that you can recognize the more common components and understand what they actually do. A number of these components are drawn below and it is interesting to note that often there is more than one symbol representing the same type of component. How to Use a Meter to Test Continuity Caution: Please read safety information before attempting any testing or repairs. This test should be done when current is NOT present. Always unplug the device or turn off the main circuit breaker before attempting a continuity test. Always test your test equipment for proper operation before use. A continuity test is done to determine whether a circuit is open or closed. For example, a wall switch is closed when it is turned to the "on" position and it is open when it is turned off. An open circuit cannot conduct electricity. A closed circuit has continuity. To test the continuity of a circuit requires the use of a multimeter (also called a multitester) or a continuity tester (a simple device that lights up to indicate continuity). Set the multimeter to the ohm setting. The symbol for ohm is the Greek letter omega. If there is more than one ohm setting, choose X1. An analog meter, like the one pictured below, uses a needle to indicate the measured value. A digital meter performs the same test functions as an analog meter, with the key difference being that a digital meter provides a numeric reading instead of using a needle. Note that while the probes are not touching anything, the multimeter will indicate a reading of infinity. A reading of infinity means that the circuit is open. When you touch the two probes together, the reading changes to zero. A reading of zero indicates that the circuit is closed or complete. A complete circuit is one that can conduct electricity; an open circuit cannot. Touch each probe to one of the terminals (or poles) of the device. If the reading changes to zero the device has continuity. To test a switch, place a probe on each pole of the switch. When you move the switch from the off to the on position, the meter reading should change from infinity to roughly zero, which implies that the switch is working. To test a component such as a motor, touch a probe to each pole. A reading of roughly zero indicates that motor has continuity and current can pass through it. You can also use a continuity tester, which is a less expensive more basic device, to conduct this test. As above, touch one probe to each terminal. If the device has continuity, the tester will light up. TESTING ELECTRONIC COMPONENTS: How To Test A Fuse With A Multimeter Typical example of fuses It’s very easy on how to test a fuse. Fuse is a very thin wire, which either melts or vaporizes when current flow through it exceeded the fuse rating. The thin wire of fuse may be made of aluminum, tin-coated copper or nickel. The resulting open in the circuit stops current to flow. In electronic equipment, most fuses are cylindrical glass or ceramic type with a metal cap at each end! The current rating and voltage also can be seen in one of the two metal end caps. There are two popular physical sizes: 1 – ¼ X ¼ - inch and 5X20mm. The 1 – ¼ X ¼ - inch size is used in many automobiles. You’ll find both sizes in many electronic equipment, but the smaller 5 X 20mm has become more common. Fuses are available with current ratings from 1/500 Ampere to hundreds of amperes. Before showing you on how to test or check a fuse, first you need to understand the purpose of a fuse. The function of fuses is to stop higher than normal current to flow to an electronic circuit-it is designed to protect equipment and save electronic components from being damaged and also stop overheating, which could cause a fire. Sometimes though there were lightning strike on an equipment, you will be surprised that only fuse were damaged and not the power supply section or components. There are two basic types of fuses which are the fast acting and slow blow type. The fast acting fuse will open very quickly when their particular current rating is exceeded. This is very important for analogue multimeter, which can quickly be destroyed when too much current flows through them, for even a very small amount of time. Even if you are an experienced repairer, sometimes we do made mistake by accidentally touching the probe to the testing points where it should not be touch! The slow blow fuse has a coiled construction inside the glass. Slow blow fuses are designed to open only on a continued overload, such as a short circuit. The function of the coiled construction is to stop the fuse from blowing on just a temporary current surge. Don’t replace a slow blow fuse in place of a fast acting fuse because it may not open fast enough to prevent components damage under a high current condition. It’s not dangerous to substitute a slow blow fuse with a fast-acting fuse, but it will probably open up unnecessarily every now and then when the equipment is first switch on such as when you switch on a Computer Monitor. A blown fuse can indicate how severe the short circuit is. There’s a secret for you, a blown fuse can indicate something about the problem. If the glass case of the fuse appears clear or transparent, and if you can still see the slight broken pieces of the fuse element, this means that there’s no major short circuit in the circuit. Replacing the fuse with one of the same type and rating usually will bring the equipment back to life again. However, sometimes a replacement might blow the fuse right away when you switch on the equipment. To save the fuse, you can use the series light bulb trick. Some fuses even die of old age because fuses have lifespan too. But if the inside of the glass fuse is black color or darkened, and there is no trace of the fuse element (the center connector), you know that there was a major short circuit somewhere in the circuit and most probably is the power supply unit. Measuring a fuse on board with an analog multimeter The common type and current rating of a fuse in a Monitor and Power Supply are slow blow 3.15A to 5 Ampere. Here is the part on how to test a fuse. Switch off the power of the equipment, remove the casing and you will see a fuse usually located in the Ac input area or power supply section. Measure the fuse with a either an analog or a digital multimeter. If you use an analog meter then select the lowest ohms range which is the x1 ohms. blown fuse in a fuse case Touch the probes to both end of the fuse. You can check the fuse while it still in circuit. A good fuse reading should showed continuity or read ZERO ohms. A blown fuse is open which will not show any reading on your meter. Testing fuse is one of the simplest tasks in electronic troubleshooting. It’s easy and fast. For fuse replacement, use only the same current and voltage ratings as the original one. RESISTOR Resistor is anything that electricity cannot travel through easily. When electricity is forced through a resistor, often the energy in the electricity is filtered. Resistors restrict the flow of electric current, for example a resistor is placed in series with a light emitting Diode (LED) to limit the current passing through the LED. Connecting and soldering Resistors may be connected either way round. They are not damaged by heat when soldering. Resistance is measured in ohms, the symbol for ohm is an omega . 1 is quite small so resistor values are often given in k and M . 1 k = 1000 1 M = 1000000. Resistor values are normally shown using coloured bands. Each colour represents a number as shown in the table. Most resistors have 4 bands: The first band gives the first digit. The second band gives the second digit. The third band indicates the number of zeros. The Resistor colour code Colour Number Black 0 Brown 1 Red 2 Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 Grey 8 White 9 The fourth band is used to shows the tolerance (precision) of the resistor, this may be ignored for almost all circuits but further details are given below. This resistor has red (2), violet (7), yellow (4 zeros) and gold bands. So its value is 270000 = 270 k . On circuit diagrams this is usually omitted and the value is written 270K. Small value resistors (less than 10 ohm) The standard colour code cannot show values of less than 10. To show these small values two special colours are used for the third band: gold which means × 0.1 and silver which means × 0.01. The first and second bands represent the digits as normal. For example: red, violet, gold bands represent 27 × 0.1 = 2.7 green, blue, silver bands represent 56 × 0.01 = 0.56 Tolerance of resistors (fourth band of colour code) The tolerance of a resistor is shown by the fourth band of the colour code. Tolerance is the precision of the resistor and it is given as a percentage. For example a 390 resistor with a tolerance of ±10% will have a value within 10% of 390 , between 390 - 39 = 351 and 390 + 39 = 429 (39 is 10% of 390). A special colour code is used for the fourth band tolerance: silver ±10%, gold ±5%, red ±2%, brown ±1%. If no fourth band is shown the tolerance is ±20%. Tolerance may be ignored for almost all circuits because precise resistor values are rarely required. Resistor shorthand Resistor values are often written on circuit diagrams using a code system which avoids using a decimal point because it is easy to miss the small dot. Instead the letters R, K and M are used in place of the decimal point. To read the code: replace the letter with a decimal point, then multiply the value by 1000 if the letter was K, or 1000000 if the letter was M. The letter R means multiply by 1. For example: 560R means 560 2K7 means 2.7 k = 2700 39K means 39 k 1M0 means 1.0 M = 1000 k (Real resistor values the E6 and E12 series) You may have noticed that resistors are not available with every possible value, for example 22k and 47k are readily available, but 25k and 50k are not! Why is this? Imagine that you decided to make resistors every 10 giving 10, 20, 30, 40, 50 and so on. That seems fine, but what happens when you reach 1000? It would be pointless to make 1000,1010, 1020, 1030 and so on because for these values 10 is a very small difference, too small to be noticeable in most circuits. In fact it would be difficult to make resistors sufficiently accurate. High power resistors 5W You will usually see this in television and monitor board. In my experience, I have seen a number of this got but in colour TV. 25W Power Ratings of Resistors Electrical energy is converted to heat when current flows through a resistor. Usually the effect is negligible, but if the resistance is low (or the voltage across the resistor high) a large current may pass making the resistor become noticeably warm. The resistor must be able to withstand the heating effect and resistors have power ratings to show this. Power ratings of resistors are rarely quoted in parts lists because for most circuits the standard power ratings of 0.25W or 0.5W are suitable. For the rare cases where a higher power is required it should be clearly specified in the parts list, these will be circuits using low value resistors (less than about 300 ) or high voltages (more than 15V). The power, P, developed in a resistor is given by: P = I² ×R or P = V² /R where: P = power developed in the resistor in watts(W) I = current through the resistor in amps (A) R = resistance of the resistor in ohms ( ) V = voltage across the resistor in volts (V) Examples: A 470 resistor with 10V across it, needs a power rating P = V²/R = 10²/470 = 0.21W. In this case a standard 0.25W resistor would be suitable. A 27 resistor with 10V across it, needs a power rating P = V²/R = 10²/27 = 3.7W. A high power resistor with a rating of 5W would be suitable SMD Resistor Code SMD stand for surface mount device and if you repair LCD monitors, you would come across Lots of SMD components. CRT monitors rarely use SMD thus it is quite easy to find out the components value. I’m going to talks about SMD resistor code and how you could calculate the values. This SMD resistor codes is different from the normal resistor color code( color bands) you had seen in the electronic circuit boards. Surface mount resistors is very much smaller in size than the normal carbon film resistor and because of this the numbers and letters were stamped upon or printed on the top side of the component. Those numbers and letters have a meaning and you could use that as information to find out or calculate the desire resistance values. Sometimes the resistors are designed in a very small size until we have difficulty to read the code. By using a magnifier glass we could easily read the resistor codes. How to Calculate SMD Resistor Code Fast SMD resistor codes is different from the normal resistor color code (color bands) you had seen in the electronic circuit boards. Surface mount resistors is very much smaller in size than the normal carbon film resistor and because of this the numbers and letters were stamped upon or printed on the top side of the component. Those numbers and letters have a meaning and you could use that as information to find out or calculate the desire resistance values. Sometimes the resistors are designed in a very small size until we have difficulty to read the code. By using a magnifier glass we could easily read the resistor codes. There are two types of surface mount resistors used in an electronic circuit board-the 3-digit and 4-digit code SMD. The first two digits represent the two digits in the answer. The third digit represents the number of zero’s you must place after the two digits. The answer will be in Ohms. For example: 104 which mean 10 0000 (4 zero’s) and the final answer is 100k. Let’s calculate the 4 digit SMD, 1182 which mean 118 00 (2 zero’s) and the final answer is 11.8k. 3 Digit Example 4 Digit Example 0R1=0.1 Ohm 0000= 0 ohms= link or jumper R33=0.33 Ohm 00R1=0.1 Ohm 8R2= 8.2 Ohm 0R47=0.47 Ohm 220 is 22 Ohm and not 220 ohms 1R00=1 Ohm 331= 330 Ohms 1000= 100 Ohm 473=47000 or 47k 8202= 82000=82k Measuring surface mount resistors is very easy with the help of digital multimeter. Most of the times when you check directly on the SMD resistors, you would get the right reading even without lifting a resistor lead. But not all digital multimeter can perform this kind of test. Select only the one that has the output voltage (measure at the probes) of less than 0.6 volts so that it won’t trigger any semiconductor devices that can give you a false reading. Once you know how to calculate the SMD resistor code and using the right way to test SMD resistors on board , you could check lots of SMD resistors in the shortest time. HOW TO KNOW THE VALUE BURNED RESISTOR If the resistor is a NON Carbon film (most are these days) its got a spirally nickel band from one end of the lead to the other under the color bands coating. What happens when a resistor overheats and burns up, is usually the metal Spiral opens up approximately dead center. 1. Carefully scrape the burnt coating off the surface & you will see the spiral. 2. Measure from each side of the break to the end lead with an ohm meter. 3. Add up the 2 values & that's about the 'ball park' of the original value. Some Technicians have reported to be able to have dropped a solder bead between the break, forming a conductive junction, and measure between the original 2 spots to get the resistor value. Test resistor without current Once a resistor has been blown, often no electricity can pass through it. Such resistors are said to have infinite resistance. At the same time, if the resistor was damaged by excessive voltage but not destroyed, the resistor may allow some electricity to pass but have an incorrect level of resistance. This is why it is so important to know about tolerances. For example, if you knew that a resistor was supposed to have a value of 200,000 ohms but tested the resistor at 180,000, you might assume that the resistor was bad. When testing a resistor, the multimeter is passing a known amount of electrical current through the resistor and then measuring the amount of current that actually makes it through. Since the multimeter is passing current through the resistor, you want to ensure that the device containing the resistor you are testing is unplugged and turned off. If a normal amount of current was flowing through the resistor and you tried to test the resistor, not only will your reading be inaccurate, but you could damage the resistor and other components. You could also damage your multimeter or receive a nasty electrical shock. With that said, multimeters are designed to use scales. These scales determine how much current the multimeter will use during the test. For example, my multimeter has scales for 200 ohms, 2 K ohms, 200 K ohms, 2 M ohms, and 20 M ohms. If I were to test our fictitious 200 K ohm resistor with this particular meter, I would set the scale at 200 K ohms. However, it’s purely a coincidence that my meter has a setting for 200 K ohms. Normally, there won’t be a scale setting that matches the value of the resistor. In such situations, you’ll want to go to the nearest scale value above the resistor's rating. For example, if you had a 100 K ohm resistor, you would use the 200 K ohm scale. If you had a 300 K ohm resistor, you’d use the 2 M ohm scale. The available scales will differ among brands and models of multimeters, but the concept remains the same. Once you've verified that the device is unplugged and powered off and that your meter is set to the correct scale, it’s time to take a measurement. Resistors aren’t polarized, so it doesn’t matter which side of the resistor you place the meter’s red or black probes on. Once you place the probes against the resistor’s leads, you should receive a value for the resistor. For demonstration purposes, I decided to use my meter to actually test a 200 K ohm resistor. The resistor tested at 197.6 ohms. This was well within the 180 K to 220 K range allowed by the resistor’s 10 percent tolerance. Had the resistor tested outside of this range, the resistor would have been bad and would have needed to be replaced.: How to accurately check resistors on board Usually when a resistor fails they either increase in value or open up at all. You can check the resistance of a resistor with an ohmmeter. If the resistor is in circuit, you will generally have to isolate the resistor so you are measuring only the resistor, not other components in the circuit. Always be aware of possible back (parallel) circuits when performing in-circuit resistance measurements. As a repairer, most of the times we want to troubleshoot and solve problems as fast as possible thus removing all resistors from the board and check the resistors one by one will take up a lot of our precious time. There have to be a simple way to check resistor on board. Using analog meter to check resistor on board often produced a wrong reading. This is due to the reason that the output from the analog meter is from 3 volt to 12 volt. The voltages are quite high and it can trigger the semiconductor devices around the resistors such as diode, transistor and ICs. Do you know that semiconductors only need voltage of 0.6v in order to conduct. Since the output voltage from the analog meter is higher than the semiconductors, checking the resistor in circuit won't give you an accurate reading! In order to measure resistors while it still in circuit, you need to get a digital multimeter that have the output of less than 0.6v. This is to avoid conducting the semiconductor devices around the circuit that you want to check. Currently i' m using the Greenlee digital meter that have output around 0.2volt. Though it cannot give me a 100% accurate result at least it can help me to speed up my troubleshooting job. Why not 100%? This is due to that some circuit has resistors that are directly parallel to each other. Testing time- If you connect your digital meter leads across a resistor in a circuit and it measures higher than it should, then you know the resistor is either open or has gone up in value. Other circuit components cannot possibly increase the value of a resistor; any parallel circuit could only make the resistance reading lower. In rare cases, sometimes an undischarge capacitor can cause the measurement higher than it should be. Only through more practice will make you know when you should remove the resistor and check it off board. for more visit