THE ART OF SUCCESS IN ELECTRONIC SERVICING By Jestine
Contents
1. Logic probe Provides a fast and easy means to indicate whether the test point is high low or pulsing Logic pulser To inject signals either a constant high or a low or a series of pulses at the inputs of a device and then read the resulting pulses and the outputs with the logic probe Logic clip Similar in appearances to the IC test clip The lower end of the logic clip fits over the pins of the IC being tested A series of LED s along the top of the logic clip indicates the logic state of each pin By feeding known signals into an IC watching the output on the logic clip and comparing the results with a truth table a technician can indicate if the IC is working properly Current tracers To detect short circuit in a board to a specific point Logic state analyzer To display the logic states of many different signals at the same time Logic comparator This device provides a convenient way of checking a faulty IC against an IC which is known to be good IC tester This tester is different from the logic comparator because it does not require the technician to have known good spare of IC being tested This tester is supervised by an on board microprocessor Analog signature analysis It works by applying a current limited AC signal across two points of a component The current flow causes a vertical deflection of the trace while the applied voltage causes a horizontal deflection Together2. Specialized Test Equipment In this section we highlight specialized equipment for repairing certain types of electronic equipment These test equipments are specially designed to tackle only on certain type of circuit or component Some repairs cannot be attempted without the help from the equipments The required specialized test equipment depends upon which part of the electronic repairing field the technician or engineer wants to specialize in Troubleshooting Monitor and TV l Flyback Tester Besides checking if the Flyback Transformer winding is shorted it also can be used to check the winding of switch mode power supply B coil and Horizontal yoke coil 2 High voltage probe To measure the high voltage at the anode of the CRT 3 Pattern generator It allows you to test and align the Monitor TV using standard visual patterns 4 CRT Tester Regenerator A CRT tester regenerator enables you to test and regenerate the cathode ray tube CRT of a Monitor or TV Page 18 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 6 Monitor TV Analyzer It is an all in one piece of equipment designed especially to test Monitor or TVs Universal Horizontal Analyzer Localize Horizontal and B supply defects in Monitor and TV Troubleshooting audio equipment l Function Generator Provides several different waveforms at a variable frequency in m
3. http groups yahoo com you can choose from the list of repairing forums that suits your field by typing the word repair in the search box http groups google com if you like electronic repair then select the sci electronic forum group Page 38 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing PART 3 3 1 Setting Up As an Authorized Service Centre ASC The following are some guidance you need to know in order to successfully become an Authorized Service Centre ASC Setting up from scratch as an ASC is not an easy job Your workshop needs to meet the manufacturers requirement first before they can appoint your company as an ASC Q Good track record a Accessibility a Location a Space a Security Manufacturers expect a company to have a good track record in the trade and have been around in the business for a long time Experience in running a repairing business counts If your company is new your chances of being appoint as an ASC would be low Usually a manufacturer would prefer a company that is located not too far from them This makes it is easy for a manufacturer to deliver products to you for repair besides saving time Another factor is whether or not there is another ASC in the locality Normally manufacturers are not keen to have more than one ASC within a specific radius A company must pr
4. Always keep a damp sponge near your soldering station and wipe the tip of the hot iron frequently while you re soldering This will keep the tip clean and shinny for maximum heat transfer Soldering Iron Holders If you have a soldering iron with no switch some soldering irons have a switch where each press will increase the power from 30w to 120w it will remain hot all the time when it is plugged in Sometimes the solder iron becomes too hot and it melts the plastic case of the soldering iron The holder is often formed into a spiral with lots of air space to radiate the heat from the iron and also to prevent the soldering tip from touching other parts which can sometimes cause fire Page 12 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Solder Solder is related by the proportion of lead to tin For example 60 40 solder is 60 tin and 40 lead The diameter of the solder that I usually use is 0 8mm Most solders are manufactured with a hollow center which contains flux As a solder melts the flux cleans the parts and prevents oxidation to ensure a good connection Always use resin core solder and under no circumstances should you use paste flux containing acids or solvents or use solder containing acid flux Harsh solvents destroy delicate components leads and circuit traces Heat guns You can often use temperature as a diagnosti
5. All Rights Reserved The Art of Success in Electronic Servicing 2 5 Sharing Knowledge and Togetherness With today s service technology going it alone will likely to lead you to frustration due to the numerous complicated new designs of the circuits Much faster servicing can be obtained by continuously consulting or keeping in touch with fellow servicemen and discussions Remember that a discussion with the right man on the appropriate subject is always fruitful Nowadays there are many technical websites found in the Internet Be a member and gain much from its facilities like repairing tips schematics latest news from manufacturers and more Some technical sites even provide a chat room where you can chat via your keyboard with others in the room Whatever the problems you re facing there s a good chance that one of the electronic repair forum members has dealt with it before An electronic repair forum is a great source of inside information This is where you discover the things that nobody can or will talk about it publicly such as Did you know that you can rewind the Monitor B coil Brand X Television keeps breaking down due to a capacitor leakage at location C124 There are 3 ways to rejuvenate a dim Cathode Ray Tube CRT even without using a CRT Rejuvenator testing equipment Here are several electronic repair forum which you can check www repairworld com general electronic equipment repair forum
6. Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 11 Lifting Some equipment like TV Hi fi or Monitor can easily weight around 15 to 30 kilogram Many problems arise when lifting this equipment from the floor Wrong posture when lifting equipment may cause acute back pain The right way to lift is keep your back straight and upright and use your legs to supply the lifting power 12 Ventilation Be sure that your work place has good ventilation Prolong exposure or excessive inhalation of vapors from chemical spray and fumes from lead may cause damage to your nervous system or body 13 Laser Warning Labels If you are troubleshooting DVD VCD laser printer and other laser related products you will notice a laser warning label on or near the laser head assembly Do not stare at the laser beam at any time Always avoid directly exposing your eyes to the beam Prolong exposure of laser beam to the eyes may cause eye injury or loss of sight Do not attempt to adjust the laser gain controls by any methods other than those described in the service manual Incorrect adjustment can increase the laser radiation beyond acceptable limits You have to use a laser power meter to confirm the existence of a laser beam Page 11 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 1 3 Tools and Test Equ
7. Jalan Cempaka SD 12 2 Bandar Sri Damansara 52200 Kuala Lumpur Malaysia http www ElectronicRepairGuide com Page 50 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved
8. a coil or a winding value Winding s value in Flyback power transformer horizontal and vertical yoke coil can be checked with the inductance meter An inductance meter will usually display inductance value directly in Henry H milihenry MH or microhenry UH ESR Meter Almost all electrolytic capacitor failures are due to high ESR Equivalent Series Resistance The high internal resistance reduces the capacitor s rate of charge and discharge effectively making it an open capacitor High ESR is usually as a result of dehydration of the electrolyte due to equipment heat old age corrosion defective rubber seal and high ripple current High ESR in electrolytic causes various problems In a monitor vertical section they can cause over under scan problems In power section they cause no power and power blink In the color or video circuits they cause intermittent or missing colors In high voltage section they cause horizontal output transistor HOT to blow several minutes after it is replaced The job of finding any high ESR in electrolytic capacitor is done by the ESR meters Note that ESR cannot be measured by a digital capacitance meter or a multimeter It has to be measured by the ESR meter ESR meters come in all shapes sizes and brand We found that a unit called cap analyzer 88A ESR meter manufactured by EDS in USA to be the best value Page 17 This E book Is Brought To You By www ElectronicRepairGuide com All Righ
9. cee s ace cscadecisweasns aks cucien vss aeanassesebaoawideses 2 4 Keeping spare parts cis occ ssa tice H cewend a ga ve ddan yaad eee edi adesse oceans 2 5 Sharing knowledge and togetherness cc cece eeeec eens eee ees PART 3 3 1 Setting up as an Authorized Service Centre ASC 6 0085 Page 4 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing PART 4 4 1 Promoting your business 00 c cece eee e eect ee eneeeeeeeaas PART 5 Conclusion Appendix About the author 3 aiiien css ise secaegdhtode ngs nadantennaaesenada enneydeaseeaiseeieorencae Subscribe to my newsletter 0 c cece cece cece cece eee eee enna tenet eee eee aes Co tact 0 ee ee et cr cer ee eee ee ee eee ee rr ere Copyright DisClanme ts iii osiiia sein iid extdaeuapsaevaeedsioavecranianstidbde stiduedansiwiad eae Page 5 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved 43 44 47 48 49 50 The Art of Success in Electronic Servicing PART 1 1 1 Introduction to Electronic Servicing With countless new electronic products or equipment reaching the market there is a large demand for electronic repair technicians and engineers As a result you may be interested in moving into the electronics repair field The electronic servicing field is considered a prestigious job
10. components in a suspected faulty circuit Overheated components in the printed circuit board are always a source of trouble Always turn off the equipment before you begin to touch on the suspected components like IC s transistor and diode Before you touch any components be careful to ground yourself by touching the case of the equipment for a moment If you don t do this you can accumulate a static charge which can damage delicate CMOS ICs Some components are hot even when they re operating normally If a transistor is attached to a large metal plate a heat sink you can expect the plate to be quite hot A transistor with a smaller heat sink should be proportionally cooler Use of the sight sound smell and touch senses will reveal the untold story of the faulty circuit and may provide helpful clues Page 29 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 1 10 State of mind As a repair technician you must start to develop the right state of mind for repairing work An electronic repairing problem requires mental discipline as well as technical knowledge Repair work can be very frustrating You may work for many hours trying to find a particular problem and make a repair only to have the problem return a week later Do not be discouraged if the equipment still malfunctions You ll have to try different approaches until you really find t
11. not an isolation transformer Page 8 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 5 Discharging the Cathode Ray Tube CRT Anode The CRT of a Monitor and TV can hold a dangerous charge even if the Monitor and TV have not been used several days All CRT have graphite coating on the internal and external surfaces of the glass bell This conductive graphite coating are commonly known as aquadag coating and it forms the two plates of a high voltage filter capacitor using the glass in between as dielectric The external coating is always connected to the Monitor and TV chassis ground by a spring arrangement around the CRT This high voltage filter capacitor has very low leakage Before removing a CRT ensure that you discharge this capacitor in order to prevent shocks or serious injuries 6 High Voltage Monitors and TV have sections that use very high DC voltages The high voltage is needed to be applied to the CRT to attract the electron beam to the phosphor This high voltage could be as low as 12 000 volt in a monochrome Monitor or as high as 30 000 volt in large color monitor Flyback Transformer is the part that is used to generate the high voltage The high voltage circuit inside a Monitor or TV can give you a dangerous electric shock and causes you to jerk violently You could cut yourself by accidentally knocking on sharp chassis edges Be famili
12. one hand while keeping the other in your pocket That keeps the possible current paths away from the heart e Don t attempt repair work when you are tired or rushed f Always assume that all the parts in the power supply are HOT g Use only plastic screwdriver for shock protection during service operation 2 Discharging Switch Mode Power Supply SMPS Capacitors Most SMPS have a resistor to drain the charge in the main filter capacitor But some resistors may fail and the capacitor can hold this charge even after you have turned off the equipment This capacitor has a range of about 150uf to 330uf at 400 working voltage Before you start to work on a power supply always turn off the power and discharge the capacitor You can do this by placing a resistor across the two legs of the capacitor The resistor value can be around 2 2 to 4 7 kilo ohms 10watt It takes only a few seconds to fully discharge a capacitor Double check the capacitor with a voltmeter after every discharge Page 7 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing NOTE WARNING Do not discharge capacitor with screwdriver because i It may melt the tip of the screwdriver ii It will damage the capacitor and its terminal iii If we are too near to the point of discharge the heavy spark generated may cause injury to our eyes 3 Hot Ground Problem Modern equipmen
13. the job information the current status of the job a listing of parts ordered for the particular job and a schedule of service performed by all technicians a Uncollected repair tie up space and money Sent notice to customer that states that if an item is uncollected by a certain amount of time the item will be sold or dispose of a Do not cheat any customer and remember once a customer feels that he is being cheated by you he will definitely not come again and will also warn others Page 31 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing a Charge reasonably so that you earn reasonably and the customer is also satisfied A happy customer is the most cost effective form of advertising often bringing new businesses through referrals Page 32 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 2 2 Time Is Money In the field of servicing time is money You can waste it or you can make money out of it The less the time you take on one job the more number of jobs you can do and hence the more you can earn Anytime the technician or engineer spends over one hour on a given electronics problem without locating the faulty component time is lost Time can be lost due to a Intermittent problem Sometimes a fault might be intermittent Dry solder joints heating lo
14. to http www ElectronicRepairGuide com to subscribe to my monthly repair newsletter Page 48 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Contact Us Mail Noahtech Computer Repairing And Services 3A 1 Jalan Cempaka SD 12 2 Bandar Sri Damansara 52200 Kuala Lumpur Malaysia Internet Email jestineyong electronicrepairguide com http www ElectronicRepairGuide com http www JestineY ong com http www TestingElectronicComponents com http www FindBurntResistorValue com Tel 603 6277 8522 Fax 603 6277 8521 Co founders Jestine Yong William Hor Page 49 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Copyright Disclaimer The author Jestine Yong and the publisher Noahtech Computer Repairing and Services have made every endeavor to produce a high quality informative and helpful book However they make no representation or warranties of any kind with regards to the completeness or accuracy of the contents of the book They accept no liability of any kind for any losses or damages caused or alleged to be caused directly or indirectly from using the information contained in this book All product names mentioned in this book are trademarks or registered trademarks of their respective companies Noahtech Computer Repairing And Services 3A 1
15. will have plenty of work but marginal profit and if you make them too high your customers will most probably switch to other competitors Charge reasonably so that you earn enough and the customers are also happy Apart from the ethical consideration reputation soon spreads and a dissatisfied customer will not come back and will also warn others On the other hand a good job reasonable charges undoubtedly bring referral business Here are some guidelines that will help you give a reasonable price quotation a Inform customer at the start If it would cost them more you will inform them If it costs less you will go ahead with the repairs a Flat rates charges for dealers Except if it involves changing expensive components such as a Cathode Ray Tube CRT or Flyback Transformer in Monitor or TV repairing The flat rate charges are inclusive of labor charge replacing passive and active components changing switch repair cable and etc This is an easy way for dealers to quote their customers a Explain to customers in detail as to why an item is beyond economical repair or not worth repairing Anyhow some customers may ask for a second opinion a Always charge a minimum bench fee if a customer decides to take back the equipment which has already been repaired The fees include the time you have spent troubleshooting the equipment and putting back the bad components which you have initially replaced a Always charge for repeated service
16. If you are really good in your work there is almost no competition and you can acquire skills that allow you to earn enough money Servicing is an ideal combination of your intelligence efficiency and easy mechanical work By gaining more experiences the efficiency and skills automatically becomes instinctive Many electronic equipment servicing operations are simpler than you may think You will be surprised to learn that most servicing problems have simple causes worn cables dirty connectors a loose screw in the works and so on Almost any end user can check for this kind of problem However there may be other problems caused by component failure You may give up and say I m not an expert in electronics You may be surprised to learn that many troubleshooting jobs do not require much detailed knowledge of electronics Even in a professional troubleshooting operation the technician or engineer may not have a detailed knowledge of the circuitry Electronic servicing is not mysterious or difficult it only requires your patience and some basic knowledge in electronics If you are thinking of becoming an electronics repair technician or engineer you need proper qualifications Get at least a certificate in basic electronics or its equivalent through electronic courses You can go far beyond this by continuing up to a diploma level As you progress you will discover your weakness It s then up to you to find out more by atte
17. The Art of Success in Electronic Servicing THE ART OF SUCCESS IN ELECTRONIC SERVICING By Jestine Yong All Rights Reserved WARNING The reader is expressly warned to consider and adopt all safety precaution that might be indicated by the activities herein and to avoid all potential hazards Although all possible measures have been taken to ensure the accuracy of the information presented neither Noahtech Computer Repairing and Services nor the author are liable for damages or injuries misinterpretation of directions or the misapplications of information By following the instructions contained herein the reader willingly assumes all risks in connection with such instructions Page 1 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing DEDICATION I would like to thank God for giving me the skills knowledge patience and desire needed to write this e book My wife Michelle Tan shared both my ideas and complaints patiently and has given me invaluable support and encouragement I would not have completed the work without her presence and advice I would also like to thank my partner William Hor and all my colleagues for their endless assistance Page 2 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Preface What you want to do in life is often related
18. You can lose a lot of valuable servicing time if you are without a good service manual The service manual is a set of document prepared by the manufacturer to help the service engineers to repair or service that set of equipment A well written manual is the best servicing aid It contains the following information a Describe how a circuit works Block diagram of the equipment Circuit diagrams Signal and voltage test points Adjustment procedure List of accessories List of spare parts with the part numbers values tolerances and ratings Fault diagnosis steps generally in the form of flow charts Preventive maintenance layout Safety precautions to be observed while handling the equipment And much much more Oooocvoodvovovcvoo so A service manual can be very expensive but it is worth the investment With the help of a service manual a service technician or engineer can a Align calibrate and test the equipment correctly to get the optimum output a Locate a fault quickly a Use the correct replacement part a Conduct preventive maintenance correctly By using the right service manual as well as with the assistance of good tools testing equipment and your own experience you are set to multiply your troubleshooting power Page 27 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 1 8 ELECTRONIC Books and Magazine With the ever changi
19. aking audio tests of the amplifier Distortion meter It is designed to measure total distortion at any frequency between 20Hz and 20 KHz Wow and flutter meter The wow and flutter meter is ideal when servicing any record playback equipment such as cassette players VCRs and etc Laser power meter To determine if the laser diode of CD players CD Rom drives VCD and DVD are working properly Noise generator You can quickly locate the defective stage at both audio and RF radio frequency circuits of the AM FM table and car radio Tone generator It can be used like the noise generator to quickly locate a dead or weak stage within the audio circuits Audio signal tracer The audio signal tracer troubleshoots audio circuits from input to the speaker Troubleshooting transmitter equipment l 2 3 Spectrum analyzer for measuring harmonics in the output Field strength meter for measuring transmitted power at a distance from the antenna RF Impedance Bridge for transmitters and antennas RF power meter for measuring RF output power SWR meter for finding standing wave ratio on feeders Page 19 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Troubleshooting digital circuit l 10 Signature analyzer A tool which gives a technician or engineer a convenient way of comparing complicated streams of data
20. ar with the high voltage circuits before you work on any high voltage equipment 7 X Radiation An X ray is a form of radiation produced when a beam of electrons strikes some material at a relatively high speed The only source of X ray in a modern Monitor or TV is from the CRT Prolong exposure to X ray can be harmful However the CRT does not emit measurable X ray if the high voltage is at the high voltage adjustment value only When high voltage is excessive then only X ray is capable of penetrating the shell of the CRT including the lead in glass material Page 9 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Test the brightness and use a high voltage probe to monitor the high voltage each time a Monitor or TV comes in for repair When the brightness is raised usually the high voltage will go down and when brightness is reduced the high voltage will go up When troubleshooting a Monitor or TV with excessively high voltage avoid being unnecessarily close to the set Do not operate the Monitor or TV for longer than it is necessary to locate the cause of excessive voltage To ensure continuous X ray protection replace the CRT with one that is of same or equivalent type as the original 8 Wearing Goggles The CRT has a complete vacuum inside It must be handled carefully and safely Always wear goggles to protect the eyes from flying glass in the
21. ardless of how complex your particular circuit or system may be a reliable troubleshooting procedure can be broken down into four basic steps Step 1 Determining failure symptoms Step 2 Identify and isolate the location of the problem Step 3 Repair and replace the suspected component Step 4 Test the equipment thoroughly after repair in order to make sure you have solved the problem and that no other problem shall arise If the problem is not solved you may try again starting from step 1 This is a universal troubleshooting procedure and you can use this procedure to troubleshoot any kind of electronic equipment Determining failure symptoms The determination symptoms of failure systems does not mean that you go straight to the toolbox and soldering tool nor does the steps mean that test equipment should be used extensively Instead the steps mean that you must know what the equipment is supposed to do when operating normally and more important you must be able to recognize when the normal job is not being done Regardless before you open your toolbox you must have a firm understanding of the symptoms Think about the symptoms carefully Many faults are identified through display on video screen or sound from speaker For example in a TV receiver if the picture is normal but there is no sound the common sections up to video detector stage are normal and the fault lies in the sound section In a stereo amplifier one channe
22. bdivided into sections that have a definite purpose or function The term function is used here to denote an operation in a specific section of the equipment For example in a color Monitor the function can be divided into video picture tube horizontal vertical high voltage monitor controls microprocessor and power supply circuits Say if the problem is the missing red color the only section you need to check is the video circuit signal cable and picture tube Identification of the faulty section eliminates the need of checking all the stages or circuits This expedites troubleshooting Once you have identified the faulty section concentrate on the circuits and ignore the remaining sections You can begin the actual repairing process and hopefully track the fault to the component level Page 25 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Repair and replace the suspected component s Now you can begin the actual repairing procedure with the help of tools test equipment and schematic diagram Inspection using the senses sight smell sound and touch is very useful in trying to locate the problem More details on using the senses to troubleshoot electronic problem is covered in a later chapter Once a faulty component is located it is necessary to reason out the cause For example if the fuse was found open there might be a cause
23. c tool Many intermittent are thermal That is they appear at one extreme temperature or another If the problem shows up only at a high temperature it may be very difficult to find with the cover removed With the cover removed the circuits usually run much cooler and a thermal intermittent will not show In this case it may be necessary to use a little heat to identify the problem A home hair dryer works well if you use the lowest possible heat setting Be careful not to overheat the circuits Certain plastic materials can be easily damaged Freeze Sprays Freeze sprays or spray coolers are available for tracing thermal intermittent They use chemicals such as Freon to rapidly cool circuit components A spray tube is included to control the application closely Thus it is easy to confine the spray to a specific component at one time Be very careful not to use just any spray coolant Some can generate static charges in the thousands of volts when they are used Sensitive devices can be damaged by static discharges so buy a brand that is specified as anti static Dental Mirrors A small adjustable dental mirror is helpful when you need to look into out of the way places especially if the components are located under the belly of the CRT Screwdrivers Screws are made in different sizes and they re designed to be turned by screwdrivers of the corresponding sizes You will need a good set of screwdrivers with both Philips and flat
24. eck for cracks broken solder joints or burnt components in a PCB board Spray Cleaner The wiper at a variable resistor might accumulate dust after operating for a certain amount of time This can result in all types of erratic or intermittent circuit problem A spray cleaner can be used to solve this kind of problem However if symptom persists replace the variable resistor Toothbrush You may use a toothbrush to look for intermittent or bad connection in a PCB board Simply run the toothbrush over the PCB board until you push the bad connection into working Most of the time you can locate the fault using this way In addition to the above listed tools some tools like table vice hammer with nail extractor and drill machine are also used in workshops especially for installation and dismantling work Page 14 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing General Test Equipment In this section we highlighted general equipment for electronic servicing Some equipment such as a multimeter is an absolute necessity for the test bench Other equipment such as a transistor tester is useful but not imperative to have In any case the more equipment you have the more prepared you will be to troubleshoot all kinds of electronic equipment problems Multimeters There are two types of multimeters in the market one is the analog while the other is di
25. ed in this book are simple but very effective and result orientated Whether you are an amateur or a professional in electronic repairing this book will be useful as a successful guide to electronic servicing Page 3 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing CONTENT PART 1 1 1 Introduction to Electronic Servicing 0 ccc c cece e cee e ence ee ees 1 2 Safety Lc See nea iaei P mneNT ne PMY ree E E eer Tew eevee Trent yrs 1 3 Tools and Test Equipment ccc cece cece eee e eee eee eee ee eneaes 1 4 WV CO cock atic one oetensababnevee nein avon useadin mlusoadeadenebaa cede 1 5 Understanding the Equipment cece cece cece eee ene eee e eens 1 6 Steps in Troubleshooting 0 00 0 c ccc ccc cece cece cence eee eee n ees 1 7 TDOCUMENIAN OD 5 eiccdoactannneonccrGcnsemaceatiesoaniahesatdeacaesiassaanmededeeaeeinies 1 8 Electronic Books and Magazine 0 0 c ccc cc cece cence cece nee e esre 1 9 Sight Sound Smell and Touch 0 0 00 ccc ccc cee ce cece ee eneeeeenas 1 10 State of mind ig onciercsaencicannusecase kenga monennaawantaavedak en amdemnaeiaaae PART 2 2 1 Good management orsccneintcideahadininetiuensinckPderekeidaciates 2 2 Timeis OU Yaoi eed paw neinei rrenen as ae eee sie ew kerai nri oats 2 3 Estimate and quotation
26. elektor com www samswebsite com www siliconchip com au www delmar com www wiley com Page 28 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 1 9 Sight sound smell and touch Sight sound smell and touch can solve a lot of electronic problems They are the most important tools and can give you a strong clue as to the source of the problem When the unit is opened it must be inspected closely with the four senses otherwise you may spend countless hours trying to find the culprit which is caused by a leaky electrolytic capacitor oil leak which you ve missed out during troubleshooting Q Q Q Q Sight Sound Smell Touch You can see a cracked printed circuit board a burnt resistor blown electrolytic capacitor arcing from Flyback transformer lightning damage cracked diode oil leak from capacitors poor board connection melted plastic of the Flyback transformer cracked CRT neck and many more You can hear a tic tic and high pitch sound from the Flyback Transformer arc over in the neck of CRT capacitor bursting while the unit is operating high voltage shutdown and arcing at the Flyback Transformer The oil from a leaky electrolytic capacitor can generate a powerful smell a burnt resistor also produces a smell and ozone smell from the Flyback Transformer You can use your finger to make a quick touch test of
27. ent All jobs coming in the workshop must be cared well against any accident They should be well attended and after the servicing they must be kept with care until it is returned to the owner There are some suggestions that lead to good management a Customer s complaint is a vital piece of information The person who is attending to the customer must be very efficient and well trained to get a precise description of the faulty equipment The details of the fault should be accurate which is very much essential before you start servicing the faulty equipment a Keep the record of all jobs and their progress until the set is repaired and returned to the customer a As soon as you repair a set write the description of the fault how you repaired the set and the components replaced When you encounter similar problems you can refer back to your record and find out what the solution was the last time This will definitely help you in the long run to cut down on time needed to solve future repairing problems a In order to speed up the job you may need a service centre software management packages that automate almost every part of your business It serves as a databank of faults their remedies and can also provide an instant reference to a particular customer generates invoices and progress reports The software management packages may also offer a method for tracking and scheduling tasks Within the tracking information the system will show
28. event of an implosion when removing and old tube from the set and installing a replacement Do not lift the CRT by the neck instead hold the CRT with both hands on the heavy glass front of the tube Also be sure to place the CRT facing downwards on a soft surface 9 Electrostatically Sensitive Devices ESD Integrated circuits IC amp some field effect transistors are examples of ESD devices These components can be easily damaged by static electricity There are several techniques which can reduce the incidence of component damage caused by static electricity a Immediately before handling any ESD devices drain the electrostatic charge from your body by touching a known earth ground b Store ESD devices in conductive foam pad until installation in circuit c Wear a grounding strap attached to your wrist d Use only a grounded tip soldering iron to solder or desolder ESD devices Some suggest using a battery powered soldering iron when working on ESD circuits 10 Fire Before returning the equipment to the user every reasonable precaution is taken to avoid fire hazards Be sure to use only direct replacements and not one that defeats some safety measure For example the fuses in your equipment are carefully designed Fuses must be replaced only with the same size type and ratings Should you install a fuse that is too large than the original rating chances are that the equipment will be flammable Page 10 This E book Is
29. every time you need a component This can take away your precious time moreover it is not economical It destroys the efficiency and presence of mind Do not make it a practice otherwise this practice will cause you financial loss Sometimes you can get spare parts from the many dead appliances as well as consumer electronic and computer equipment for your electronic repair Below is a list of components frequently used in servicing Resistors 14w 2w lw and 2w Preferred values 0 1Q to 10mQ Variable Resistors potentiometer 1kQ 5kQ 10kQ 50kQ and 100kQ Capacitors Preferred values 10pF to 4700UF Fuses fast and slow blow Ratings 0 5A to 6 3A and also include 13A fuse Zener Diodes Preferred values 2 4V to 30V Diodes 1N4001 to 1N4007 1N5401 to 1N5048 and include some ultra fast recovery diode Bridge Rectifiers KBL04 KBL06 KBL08 Voltage Regulator IC 7805 to 7812 and 7905 to 7912 Page 36 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing IC Transistor FET Depends on what type of equipment you repair Solder spares Elements tips Led s Mixed On off switch Mixed Once you are fully equipped with the essential tools test equipment and components the servicing are easy and the actual efficiency of repair can be well judged Page 37 This E book Is Brought To You By www ElectronicRepairGuide com
30. gital Some people call them multimeters or just meters while other might refer to them as volt ohm meters VOMs or multitesters Regardless of which name you choose to call them multimeters are the handiest and most versatile piece of test equipment that you will ever use The analog meter can measure ac and dc voltage current and resistance and uses a meter to read out the test results A digital multimeter DMM performs the same functions but it produces a digital display DMM are ranked by the number of digits they display A 3 2 digit DMM will indicate three numbers for each reading The half digit is reserved for character like 1 or 1 The more sophisticated meters automatically choose the correct voltage or resistance range This feature is called auto ranging DMM are easier to read more tolerant of operator error and more precise than their analog multimeters A good DMM also include features like a capacitance checker frequency meter continuity checker and transistor checker The diode setting is used for checking all solid state devices such as ICs diodes transistors SCRs and so forth Oscilloscope Oscilloscopes offer a tremendous advantage over multimeters An oscilloscope or scope can give you a picture of a changing electronic signal Instead of reading signals in numbers or lighted indicators an oscilloscope will show voltage versus time on a graphical display Not only can
31. he causes of the problem If one idea doesn t work try something else try yet another idea and keep this up until you re successful Try not to work when you are tired upset or frustrated Try to avoid working under the pressure of deadlines although this isn t always possible Always set the equipment aside after working on it for long hours Time is lost if you keep working on it Simply walk away clear your head and start again by defining your symptoms You may also try tackling it first thing in the morning when your mind is clear You should also realize that there may be more than one bad component to deal with Be prepared to make several repair attempts before the equipment is repaired completely As you gain more experience with repairing work yov Il begin to recognize the state of mind that brings good results The experienced technician is cool and rational and this gives them a huge advantage over the amateur who tends to work without a plan Page 30 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing PART 2 2 1 Good Management If you start a servicing centre good management together with honest nature your behavior and efficient servicing will earn you regular flow of job and credible reputation and of course money The amount of money that you earn in servicing is entirely up to you It requires only one thing sincere involvem
32. ing circuit Analog Television may have difficulty in repairing Digital Television He will takes a longer time to analyze the new circuit to learn new ways of troubleshooting digital circuit problem and learn how to replace surface mount components SMD All these will consume his time What about the latest technology of PLASMA TV It may be even more time consuming to understand the new design and circuit a New symptom which I believe you will agreed with me that even though you have you have not seen been in the repairing field for more than 10 years some before symptoms you might have not seen before whether you are servicing TV Monitor VCR DVD and etc Due to the new symptom it will take you a long time in finding the exact location of the fault In order to speed up your repairing job and make additional money you must master the correct techniques of servicing and learn the logical approach to identifying fault quickly You must equip yourself with knowledge of the right kind of tools and test equipment in servicing field and do your best to repair it Page 34 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 2 3 Estimates and Quotation Repair pricing is different from one service centre to another It all depends on your competitors location overheads and the value of the item to be repaired If you make your estimates too low you
33. ipment This chapter introduces you to the tools and test equipment needed for electronic troubleshooting You will need an assortment of tools and test equipment ranging from simple tool such as the screwdriver to sophisticated equipment like the Digital oscilloscope Some simple fault of electronic equipment can be repaired by using only basic tools and test equipment But if you are repairing electronic equipment for a living or you want to be ready to repair all kinds of electronic problems that come your way you will need to invest in some specialized equipment You can then be ready to move quickly when trouble strikes Tools Tools are the basic requirement of a service technician or engineer Without tools one cannot even open the cabinet and have access to the circuits Soldering Irons Transistor and ICs can easily be destroyed by overheating For this reason you must choose carefully when you select a soldering iron for use with digital circuit like CMOS IC Use a low powered iron with a rating of about 30 watts Do not use a high powered iron because it can easily overheat an IC or other parts If you overheat a trace on a circuit board the heat can cause the trace to lift from the board Soldering tips can be manufactured in a wide range of shapes and sizes Before you select the best tip for the job you must understand the ideal soldering conditions Remember to turn off the equipment before you make any solder repairs Sponges
34. its of up to SA amps protects both the power supply and the device under test from damage Page 16 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing A power supply is useful in troubleshooting for example when you suspect that the microprocessor causes the Monitor cannot be turned on You can always place 5 volts to its VCC input pin of the microprocessor and check if the outputs are producing any signals The power supply can be used with other circuits such as circuit in power section video drivers oscillators and etc Capacitance Meter Without a capacitance meter it is sometimes difficult to determine a capacitor s value Choose a capacitance meter that accurately measures the value of any capacitor between 0 1PF to 20 000ur Capacitance meter will usually display capacitance in microfarad uf Nano farad nf or Pico farad pf As long as your reading is within the tolerance of the capacitor s marked value you know the part is good It is best used to check fixed capacitor ceramic Mylar etc For electrolytic type of capacitor an ESR meter is preferred Some DMM is also equipped with a built in capacitor checker Always discharge a capacitor before testing Inductance Meter Most inductance meter comes together with the resistance and capacitance measurement range It is also called the LCR meter Inductance meter is required to determine
35. k the newspaper deliveryman to deliver it for you for a certain amount of fee Place your advertisement in the category that suits your business For example if you repair TV then put it under the category of Electronics Equipment repair and servicing or just TV repair Advertise only to the trade directories that are related to your repairing business If you repair computer monitor and printer then select the computer trade directory for advertisement Page 41 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing a Website If you have additional budget you could invest it on developing a website for your company Your website need not to be complicated but you should at least include in necessary information like your nature of business your services or products and contact details e g email address in order for customer to make enquiries to you Use letter fax and telemarketing A letter or fax to your targeted customers and telephone calls followed by a personal visit will usually yield good results This proofs to your customers that you are serious about the business Hiring a salesman If you can afford to hire a salesman then go ahead With the help of a salesman you can concentrate on repairing work and manage your company at the same time A salesman might bring you big contracts with hospitals schools hotels and factories This wi
36. l is working normally but the other is not the defect is obviously in the other channel Ask yourself what is happening If the stereo amplifier is a new installation perhaps the audio cable in the speaker box was not fixed If you have not been using your stereo for a while do you remember the last time you switched on the stereo Does the sound slowly fades away or completely does not have sound By recognizing and understanding the symptoms you definitely know that something is wrong and have a fair idea of what is faulty but you probably do not know just which area or location of the equipment is faulty This is established in the next step of troubleshooting Page 24 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Identifying and isolate the location of the problem Before you try to isolate a problem within the equipment be sure that the equipment is in fact causing the problem For example if a Monitor has a missing red color do not charge into the set with the screwdriver and soldering tool Be sure that the Monitor is the cause of the problem by comparing a known good Monitor or testing the faulty Monitor in another PC Sometimes a defective video card in your PC also can cause the missing red color symptom When you are confident that the equipment is faulty you can begin to identify possible problem areas Most electronic equipment can be su
37. ll guarantee a stable source of work and a secured future Once yov ve have got hold of a new customer give them the best service because in return your customer will promote your business through word of mouth referrals A happy customer is the most cost effective form of advertising often bringing much new business through recommendations No costs involve and this usually means that the new customer has a positive attitude towards you before you even have to do any work for them Page 42 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing PART 5 Conclusions With the information you have acquired you should have a basic understanding of how to repair equipment run a technical department set up your own repairing business promote your repairing business and even the requirements to become a competent Authorized Service Center If you begin a servicing center remember that good management honest nature your attitude and efficient servicing will make you a successful business person Quote Success is a ladder that cannot be climbed with your hands in your pockets Page 43 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 10 11 12 Suggested Technical Reference Books Basic Electronics Eight Editions Electronics Principles and Application
38. nd of detailed knowledge is helpful of course but it is not necessary As a technician you normally won t have to deal with all the details of a circuits functioning You don t have to design the equipment but all you need to do is to ensure that it is functioning Any piece of faulty equipment was once working as such you can assume that all of the complex design problems have been taken care of by the engineers All you must do is to bring the equipment back to life Once you fully understand the circuit function it is easy for you to breakdown each and every section of a circuit and use the right tools and test equipment to pinpoint the faulty components within a very short period of time For example if a customer tells you the Monitor color is out 1 e yellow display your knowledge will prompt to you that the power supply vertical and horizontal section is working fine The problem may lie somewhere within the signal cable CRT board or even CRT This can narrow down the problem and save your troubleshooting time Page 23 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 1 6 Steps in Troubleshooting Knowledge of the right troubleshooting procedure and its intelligent application is essential for correct and quick diagnosis of the fault Fault diagnosis is the acquired skill in being able to locate a fault quickly within any circuit or system Reg
39. nding professional courses or reading up related books Of course the higher the level you desire the better Every second electronic equipment breaks down and we will need good technicians and engineers to ensure a good repairing job is done So if you are thinking of joining us go for it Page 6 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 1 2 Safety First Whenever you re working on any electronic equipment your own safety has to come first Every electronic technician must always take safety precautions before he or she starts work Electricity must be handled properly or else it can injure or cause fatalities Here are some basic steps that show you how to avoid accidents from occurring 1 Electrical Shock Once you open up a set cover you re actually exposing yourself to the threat of electric shock Always keep in mind that safety has to come first A serious shock may stop your heart and if large electric current flows through your body you will receive serious burns Here are some rules which should help you to avoid electricity hazards a Always turn off the equipment and unplug it before you begin to work b Ifyou have to run tests while the equipment is operating turn the equipment on make your test carefully and then turn the equipment off again c Wear rubber bottom shoes or sneakers d Try to do the work with
40. ng and Repairing and LCD Monitor Repair Jestine is the author of the e book How to Find Burnt Resistor Value and Testing Electronic Components and he is currently working on his third e book You can be sure that he will share his knowledge with all enthusiasts out there Residing in Kuala Lumpur Malaysia with his wife Michelle Tan Jestine is blessed with two lovely children Noah and Hannah He enjoys writing internet marketing reading fishing and traveling during his past times Page 47 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Subscribe To My Repair Newsletter If you want updates on the latest electronic repairing news then I personally recommend you to log on to my website regularly or sign up for my free monthly Newsletter Things that you can expect to receive with the free subscription include gt gt Repairing tips tricks gadgets and strategies to skyrocket your repairs Tips and articles on running and promoting an electronic repairing business News and notes on the electronics industry and manufacturers Review of the hottest and latest repairing tools test equipment and technical books How electronic components function and the right equipment to measure them Hot links to other electronics repairing websites Updates on the arrival of the latest technical e books And much much more Go
41. ng electronic servicing and continuous development of the industry electronic technicians have to constantly update themselves with the latest developments Besides attending the manufacturer s service meetings they must read books and magazine on electronic servicing Books and magazine can be your most cost effective servicing tools Most of the books and magazine are written by people who have been in the trade for some years and they are able to pass on their invaluable experience to the readers New repairing techniques the latest troubleshooting tools and test equipment problems and solutions on certain electronic equipment will be revealed to you through the books and magazine Always be on the look out for good books and magazines There is another type of book which is essential for any repair technician It is called data book or data manual A service technician can find out the equivalent transistor through this book if the original one is not available Make dimensions pin outlines input and output voltages and switching characteristic are also provided It contains data not only of the transistor but also of diodes thyristors IC etc Data book is a valuable aid for the service technician and it is an essential item for any electronic workshop library Here are some websites that links to related information on Electronic Books and Magazines Electronic Books ElectronicMagazine Www newnespress com www
42. ntals Consumer Electronics Component Homebook How to Identify Locate and Test Consumer Electronic Components Complete Microwave Oven Service Handbook Operation Maintenance Troubleshooting and Repair Build Your Own Test Equipment Test Equipment Guide Oscilloscope Guide Page 46 By By By By By By By Homer L Davidson MCGrawhill Publication John A Ross Prompt Publication Homer L Davidson MCGrawhill Publication Carlton Gallawa Carl J Bergquist Prompt Publication Engineering Staff of Sams Prompt Publication Dr Arnold Banks Prompt Publication This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing About The Author Jestine Yong is Co Founder of Noahtech Computer Repairing and Services which has entered its 11 years in operation He has vast experience in repairing monitors power supplies computer peripherals and related electronics troubleshooting A graduate from the Robert Gordon University Aberdeen UK with a Bachelor of Science in Electrical and Electronic Engineering Jestine takes pride in active contributions to the field through the sharing of electronics repairing knowledge and expertise Within Noahtech Jestine also serves as a lecturer in conducting technical workshops such as Introduction to Testing Basic Electronic Components Basic Advanced Practical Monitor Troubleshooti
43. ose connectors etc may cause intermittent faults Such faults are the most difficult to locate a Non availability of After spending countless hours of repair you ve been told Spare parts by your supplier that the defective part that you need is no longer available in the market a Callbacks or repeated This will usually cost the electronic technician extra money Repairs The technician has to repair the problem without additional charge unless it is a different problem It is advised that doing a good repair job at the beginning eliminates repeated callbacks a Equipment that had An inexperienced technician will usually cause more trouble been badly repaired than solving the original problem Many sets come in with by someone missing components cables connected to the wrong location components installed in the opposite direction unsolder tracks wrong part numbers as substitute for the original components and etc The technician might take extra time to locate the faults and time is loss during the repairing process A half an hour job might take him three or more hours to solve it and at times the equipment is beyond repair a Understanding new Understanding the new design of electronic circuit may take Page 33 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing design of electronic you time For example a technician who is good in repair
44. ovide enough space to cater for their products Manufacturers would not prefer to appoint a company to become ASC if the working space is too small or cramped A light industrial unit would be fine for them A decent alarm system is essential to prevent easy break ins You must have the responsibility to take care or protect your manufacturers products Any break in will cause you to lose business and tarnish your company s name Page 39 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Q Reception Area Ifa manufacturer is interested in appointing your company as an Service Centre Management Software Tools and Test Equipment Employee ASC you will almost certainly be paid a visit A proper reception area neat tidy and well managed workshop will reflect on them as well First impression counts a lot Using a good computer system and service center management software will boost the manufacturers confident in your company because it can speed up the job by providing daily business Operations such as status of repair parts inventory control and etc The variety of tools and test equipment available will be taken into consideration An oscilloscope frequency counter SMD rework Station ESR meter are some initial requirements The workbench should be of decent size and comes with fluorescent lightings There must be enough
45. s Fifth Edition Electronic Troubleshooting Handbook The Art of Electronics The Illustrated Dictionary of Electronics Eight Edition ECG Semiconductor and Replacement Guide UP To Date World s Transistor Diodes Thyristors amp IC s Comparison Tables Volume I and II RS Components Catalogue Get a free copy from your local distributor Farnell Components Catalogue Get a free copy from your local distributor Basic Television and Video Systems Sixth Edition Troubleshooting amp Repairing Solid State TVs Third Edition Troubleshooting amp Repairing Color Television Systems Page 44 By By By By By By By By By By By Bernard Grob McCGrawhill Publication Schuler MCGrawhill Publication John D Lenk MCGrawhill Publication Paul Horowitz and Winfield Hill Stan Gibilisco MCGrawhill Publication By ECG Philips Tech Publication RS Components www tswww com Farnell www farnell com Bernard Grob MCGrawhill Publication Homer L Davidson MCGrawhill Publication Robert L Goodman MCGrawhill Publication This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 13 14 15 16 17 18 19 20 21 22 23 24 25 Television Electronics Theory and Servicing Eight Edition Practical TV amp Video System Repair Digital HDTV S
46. say a shorted rectifier in power supply section which made it blow The cause should first be removed If there is no short fuse might go off due to some momentary surge of current transient and in that case it can be replaced without further investigations After the fault is located it is to be rectified The process of rectifying the fault is called repair or corrective maintenance The next step is to remove the cause first and then to replace the defective component with a new one The new component for replacement should be of the same value ratings tolerance size and any other specifications as per the manufacturer of the original component Test the equipment thoroughly after repair After the equipment has been repaired the equipment must be carefully re assembled and tested Run a thorough test to check the equipment and determine if the problem is solved Thorough checking of the equipment is called servicing Do not be discouraged if the equipment still does not work Simply walk away clear your mind and start again by defining your symptoms Page 26 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 1 7 Documentation It is difficult to repair any piece of complicated equipment without some service literature It is possible to repair electronic equipment without the service manual but it can be very time consuming
47. slotted heads Many people have the habit of trying to turn a screw with whichever screwdriver they have Most screws can be turned easily if you use a screwdriver of the right size A power screwdriver is also useful in electronic servicing because some equipment have numerous screws that your hand will get tired unscrewing them Page 13 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Long Nose Pliers A long nose pliers is needed to remove components once they are desoldered from the PCB board They are very useful for reaching into tight spaces inside the equipment For example components located under the belly of the CRT are very difficult to remove without pliers Wire Cutters Wire cutters are useful for cutting wires wire ties and lead on large parts such as resistors and capacitors Wire Strippers Before you can make connections with a piece of wire you must strip away the plastic insulation on a wire Resist the temptation to strip insulation using wire cutters Even if insulation should be removed successfully wire cutters often leave a nick or pinch in the conductor which later might fatigue and break Magnifying Lamp A magnifying lamp not only provides light but also makes it easier to read component marking especially the surface mounted components SMD and small resistor color code A magnifying lamp also can be use to ch
48. t consists of two grounds one of which is a hot ground while the other is a cold ground Hot ground is in the primary side of a switch mode power supply while the cold ground is the equipment ground Be careful when taking voltage measurements around these grounds For example if you want to check the primary circuit of a power supply with power on always ground your meter or scope to the hot ground while check the secondary side using the cold ground If the Hot ground is not used and you use only the cold ground the voltage measurement might not be correct and it may destroy your meter One way to prevent this is to use an isolation transformer 4 Isolation Transformer When servicing any electronic equipment always use an isolation transformer to protect yourself from an electrical shock During servicing the isolation transformer is connected between the equipment and ac power line An isolation transformer is a transformer that has a 1 1 turn ratio to provide the standard line voltage at the secondary outlet This means that it does not change the voltage The transformer still produces 240V AC at its outputs but both sides of this AC lines are independent of ground If you were to accidentally touch one of these outputs you would be protected The isolation transformer must be rated to handle the power of any equipment connected to it Typical ratings are 250 to 500W Note A variable transformer or variacs is
49. they form a unique V I signature that represents the overall health of the device under test Analyzing the signature can quickly determine whether the component is good bad or marginal Digital oscilloscope This equipment digitizes each sample and stores it in memory Page 20 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Thus if you are looking at a spurious event i e a glitch you can capture the event and view it as long as you want You can also save the waveform to disk so that you can recall it later Compared to analog oscilloscope the glitch would just be a flash on the screen and then it disappears Digital oscilloscope is also essential for critical timing measurements Page 21 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 1 4 Workshop Before you begin to repair any electronic equipment you need a conducive work area where you can perform your repairs The requisites of a good workshop are as follows a The workshop should have 3 pronged grounded electrical outlets good lighting and well ventilated Your work area needs a very good lighting system Some electronic equipment uses Surface Mount Devices SMD which is very small thus making it difficult to identify the value or part number Without good lightings you will have trouble identif
50. to an early interest My first interest in electronics developed at the age of eight or nine there s where I began to dismantle toys and torch lights I wondered how and why with the use of batteries a motor can rotate and a bulb lights up Quite often I will dismantle a working toy into many pieces to find out what is really inside the toy causing it to move and make noises After thorough research I will usually end up being unable to put back the parts that I have dismantled PII just keep the parts motor speaker gear electronic board screw or whatever I can salvage to place it into my cabinet Whenever I have the time I will build my own circuit using the parts that I have salvaged Although I was too young to understand the math s and science of electronics at that time I found that making things work and a little bit of troubleshooting was indeed very fun Due to this investigative instinct I decided to choose the electronics repair industry for my career In the years that followed I ve learned a lot about electronics and troubleshooting The purpose for me to write this book is to help other electronic enthusiasts technicians and engineers who want to troubleshoot any kind of electronic equipment as quickly as possible Although you may already be using some of the information in this book still I am sure that some information may be new to you The troubleshooting procedure and repairing business strategies explain
51. transistors much more easily using a special transistor tester A transistor tester does a more thorough job at checking transistors than you can do with just a DMM Many different types are available in the market Transistor tester allows you to make an in circuit test without removing the transistor from the circuit board The tester indicates whether the transistor is working and it also allows you to measure the gain or output of the part Most transistor tester can also measure diodes Frequency Counter Some DMM is equipped with a built in frequency counter that can read frequency directly The ranges available is dependent on your particular meter Simple handheld meters can often read up to 100KHz and bench top multimeters can handle 1OMHz or more A frequency counter is useful for checking the frequency of for example the horizontal and vertical sync signals coming from the computer and the clock signal of the Monitors microprocessor DC Power Supply In your servicing work you will sometimes need to provide power to parts of a circuit board without using the equipment output supply for troubleshooting purposes The output of the power supply should be regulated so that the output voltage doesn t change as the power supply is loaded I use a digital type of DC power supply which is a regulated power supply It has a voltage range of between 0 and 30 volts and current range from 0 to SA The adjustable current which lim
52. ts Reserved The Art of Success in Electronic Servicing for our repair shop Cap analyzer 88A is a powerful ESR meter user friendly robust versatile and capable in locating bad or shorted electrolytic capacitor while still in the circuit This unique meter uses a test frequency higher than most others gt 100KHz automatically discharges the capacitor under test checks for DCR DC Resistance leakage then checks and display ESR on a 20 segment LED bar scale It includes a low capacitance one handed tweezers test probe and even beeps from one to five times depending on the ESR reading of the capacitor Because it is microprocessor controlled it has more features and is much more accurate than other meters Possibly its best attribute is a three colored chart on the front panel that shows typical ESR readings of good fair and bad capacitors depending on their capacitance The cap analyzer 88A checks capacitors in circuit accurately because the frequency is high enough to magnify the capacitor s actual capacity and measures only the ESR Both DCR and ESR measurement are under 50 milivolts so that no active devices are turned on Because it checks DCR first it will alert the technician immediately if the capacitor or anything else in that circuit is shorted or leaky before it checks ESR Portability and battery operated this makes it ideal for repairs at the site eliminating a double service call and valuable technical travel time
53. well trained technicians or engineers to cope up with the repairing work Prolonged or continuous delay of repairing work will make them to reconsider another service center To run an Authorized Service Centre there must be total commitment and dedication but it will guarantee plenty of satisfaction and a secured future It can also broaden the product range that comes your way Page 40 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing PART 4 4 1 Promoting Your Business If you recently set up a business you may need to advertise your business If your repairing shop isn t getting any customers no matter how good or skillful you are you may be out of business in a very short time There are many ways in which you can promote your business Advertising Q Local Newspapers Magazines Leaflet Drops Yellow Pages Local Trade Directories Advertise your repairing shop in the service section of your local newspaper Although it is a bit expensive the results are tremendously good If you provide a specialist service such as the repair of TV Tuner or the supply of schematic diagrams considers an advertisement in the electronics or hobby magazine Flyers can be delivered to nearby households You can do it on your own or engage a leaflet distributor service Sometimes you can slot in your leaflets into the newspaper and as
54. when the original repair had nothing to do with the present problem a Do not work for nothing make a fair charge You may have different ideas about this but in my opinion the system outline above is effective Page 35 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 2 4 Keeping Spare Parts A good and successful repairing technician must be equipped with numerous components and spare parts commonly used in electronic servicing Time is saved by speedy diagnosis but wasted during actual repairs You have diagnosed the cause of a fault in record time then spend twice as long searching in your spare parts box for a suitable replacement or order it and find some day later that one was there all the time hiding in the corner Time and money are wasted if you do not set up a proper parts management If it took you more than few minutes finding a spare part you probably wasted many hours a month and several days a year A wide range of electronic components is required even at the initial stage of starting the servicing job A day spent on introducing a new setup or parts management will pay for itself many times over A parts management system can be inexpensive to setup and easy to maintain Once it is properly setup what you need to do is just monitor the stock level before it falls to a minimum level It is not possible for you to run to the market
55. ying its components a It should be well equipped with test instruments and tools and should have sufficient storage space for spare parts and related accessories a Floor material should be anti static non sticky easily cleaned and non slippery It should be kept clean of dust dirt webs insects etc a The workshop should have fire extinguishers and a first aid kit box a The workbench should be equipped with a complete power strip with surge protectors fluorescent lighting and a magnifying lamp A magnifying lamp does not only provide light but also makes it easier to read component markings a The workbench also should have sufficient space for keeping test instrument tools soldering iron and the set under test a There are many other accessories that makes electronic repairing easier which includes jumper cables power cords and chemicals just to name a few Good planning of a workshop will make people enjoy working there Page 22 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 1 5 Understanding the Equipment Before you start troubleshooting any kind of electronic equipment you have to first understand how it works As a technician you must develop the right level of understanding required to repair the equipment efficiently Most beginners assume that this means you must understand every parts or function of a circuit This ki
56. you observe ac and dc voltages but are also very helpful for checking the shape of an electronic signal If you know what kind of signal to expect and the scope shows you a different signal you know something is wrong The scope may be used to check the operating characteristics of parts like transistors and capacitors Oscilloscopes have been used for many years to troubleshoot power supply amplifiers and other analog devices Page 15 This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing Don t get the idea that you will need an oscilloscope for every repair For example you need to check the presence of horizontal and vertical signal in the input and output of a microprocessor IC It is also useful in checking the proper Red Green and Blue RGB signal in the video circuit Without an oscilloscope it is difficult or almost impossible to trace the problem The better the scope the higher the frequency of the signals that it can display and much more expensive Analog scope with 40 to 60 megahertz MHz bandwidth will serve you well Some dual trace scopes can display two signals at once This allows to you check the timing relationship of two related signal If you have used an oscilloscope then you probably know just how useful they can be Transistors Tester You can make some simple tests on transistors using just a DMM However you can test
57. ystems Troubleshooting and Repair Guide to TV Second Edition TV Troubleshooting and Repair Troubleshooting and Repairing Computer Monitors Second Edition Computer Monitor Troubleshooting and Repair Power Supply Troubleshooting amp Repair Troubleshooting amp Repairing Computer Printers Second Edition Practical VCR Repair Maintaining and Repairing VCRs Troubleshooting amp Repairing Audio Equipment Third Edition Troubleshooting amp Repairing Compact Disc Players Third Edition Page 45 By By By By By By By By By By By By By Milton Kiver and Milton Kaufman CBS Publisher amp Distributors John Ross Delmar Thompson Learning Robert L Goodman Prompt Publication Engineering Staff of Sams Prompt Publication Engineering Staff of Sams Prompt Publication Stephen J Bigelow MCGrawhill Publication Joe Desposito and Kevin Garabedian Prompt Publication Lanny L Logan Prompt Publication Stephen J Bigelow MCGrawhill Publication David T Ronan Delmar Thompson Learning Robert L Goodman MCGrawhill Publication Homer L Davidson MCGrawhill Publication Homer L Davidson MCGrawhill Publication This E book Is Brought To You By www ElectronicRepairGuide com All Rights Reserved The Art of Success in Electronic Servicing 26 27 28 29 30 31 32 Troubleshooting amp Repairing Camcorders DVD Player Fundame
Download Pdf Manuals
Related Search