How electronic things work Electronic equipment ''on the blink''? Don''t junk it or pay sky-high repair costs - fix it yourself! Here''s a guide to understanding and repairing electronics equipment written for people who would ordinarily ''call the shop''. With this fully illustrated, simple-to-use guide, you will get a grasp of the workings of the electronics world that surrounds you - and even learn to make your own repairs. And you may even start enjoying it! Whether you want to pocket the savings on repair bills, give your beloved equipment the best possible care, or merely understand how it all works, this book will show you how in easy-to-understand language and clear illustrations - and you don''t need any technical experience. Written by a technician who has fixed virtually everything that plugs into a wall, this handy do-it-yourself introduction to home and office repair delivers: clear explanations of how things work, written in everyday language; easy-to-follow, illustrated instructions on using test equipment to diagnose problems; guidelines to help you decide for or against professional repair; tips on protecting your beloved equipment from lightning and other electrical damage; and, lubrication and maintenance suggestions. This is an ''Electronics 101'' for true beginners. Next time your equipment acts up, don''t get mad. Get it working - with a little help from this book. This book features how to understand (and fix): color TVs, DVDs, wireless cellular phones and PDAs, radios, speaker systems, audio/video tuners, CD players, monitors, camcorders, copiers, and fax machines.
Door will not open and/or disc will not load 1 Dirty mechanism or broken or worn gears. Clean the slide assembly or replace the drive assembly. 2 Dirty drawer switch. Clean the switch assembly. 3 Shorted motor assembly. Replace the loading motor. Disc has erratic speed Dirty or dry spindle. Clean and lubricate spindle. Laser beam will not track properly 1 Dirty or dry spindle. Clean the sled assembly. 2 Motor may be defective. Replace the motor. DVD Player Precautions ■ Before connecting any other components to your player, be sure all other components are turned off. ■ Do not move the player while a disc is being played. The disc may get scratched or bro- ken, and internal parts may become broken or misadjusted. ■ Do not place any container with liquid or any small metal objects on the unit. ■ Be careful to not place your hand into the disc tray. ■ Do not place anything other than a disc into the disc sliding tray compartment. ■ Outside influences such as lightning, power line glitches, and static electricity can af- fect normal operation of a DVD player. If this occurs, turn the unit off and then on again with the ON/OFF buttons, or disconnect and reconnect the ac power cord to the power outlet. This will reboot the player and it should operate normally. ■ After using the DVD player you should remove the disc and turn off the unit. DISC HANDLING PRECAUTIONS ■ Do not touch the disc’s signal surfaces. Hold them by the edges or by one edge and the hole in the center. ■ Do not place labels or adhesive tape to the signal surface of the discs. ■ Do not scratch or damage any portion of the disc. ■ Do not use a damage (cracked or warped) disc. CLEANING DVD DISCS ■ Dirty discs can cause reduced video and audio performance. ■ Always keep discs clean by wiping them gently with a soft cloth from the inner edge to- ward the outer perimeter. ■ Should a disc become very dirty, wet a soft cloth in water, and wring it out well. Wipe the dirt away gently, and remove any water drops with a dry cloth. ■ Do not use record-cleaning sprays or antistatic agents on DVD discs. DVD PLAYER PRECAUTIONS 377 DVD DISC CLEANING CAUTION: 378 DVD SYSTEM OPERATION DVD Player Front Panel Control Locations Refer to the DVD player control callouts shown in Fig. 11-11 as we review their operation: Disc tray Press open-close to open and close the disc tray. Skip back Allows you to move to the beginning of the preceding title, chapter, or track on a disc, thus skipping that particular title, etc. Skip forward Allows you to move to the beginning of the preceding title, chapter, or track. Play/pause Begins disc play (and closes disc tray if open). When pressed during play- back, pauses disc play. Stop Stops the disc from playing. Front panel display Reads out information for all functions of the player and disc. Random Changes play mode to random (plays the disc tracks or chapters in a random order). TS surround Use the TS surround button to simulate surround sound. Each press of the button toggles the setting between ON and OFF. ON/OFF button and ON/OFF indicator light This button turns the player on/off man- ually. The on/off indicator lights up when the DVD player is ON. Do not clean the DVD discs with benzene, thinner, or other volatile solvents that may cause damage to the disc surfaces. FIGURE 11-11 Callouts of controls found on a typical DVD video player. Personal Video Recorders (PVRs)–TiVos The personal video recorder (PVR) is a machine that uses a hard disc like that found in a per- sonal computer (PC) to let you record TV programs, at the time they are on, automatically, without having to make complex programming as with a VCR unit. This cutting edge tech- nology is certainly not a glorified VCR-type taping machine TV program recorder. As an example, the PVR machine lets you record any upcoming program, just by select- ing the title from an on-screen program guide and instructing the TiVo to record the show each time it is aired. These localized TV program guides are automatically downloaded to the PVR via your phone line or in some cases from the dish for satellite service. After they have been recorded they can be played back from an on-screen menu. The PVR machine can also search out and record selected types of movies or programs, such as “mystery types,” even on less popular channels at any time of the day or night. Another plus is that the PVR unit can automatically record whatever live program is cur- rently being transmitted and put it into its data buffer for 30 minutes or more. This feature lets you go back and do your own sports replays or pick up viewing the program after you may pause it to answer the phone or leave the TV set for more important reasons. And another fea- ture, one that advertisers won’t like, is the ability to fast forward right through commercials while watching recorded programs or live shows that you have paused for a short time. You will also find combination PVR units, such as Motorola’s and Atlanta Inc.’s, that have cable set-top boxes with the recording hard drive features. There is also Microsoft Corp.’s UltimateTV, a DirecTV receiver with a personal video recorder as well as Web- surfing capabilities. Sonicblue has plans to integrate a PVR system in its ReplayTV machine. At this point this technology can be used to manage digital video for all kinds of informa- tion sources into the customer’s home. REPLAYTV 4000 SERIES PVR SYSTEM The ReplayTV 4000 PVR machines have some expanded capabilities, such as enough memory for 320 recorded hours. The ReplayTV 4000 consists of four models: the 4040, 4080, 4160, and 4320. The numbers after the “4” indicate the amount of digital memory storage in hours; the numbers also indicate the sizes of the internal hard drives: 4040 has a 40-gigbyte hard drive, the 4080 has an 80-GB hard drive, 4160 has a 160-GB hard drive, and the 4320 has two 160-GB hard drives. All of the other features are the same on the 4000 series machines. As noted previously, the PVR’s ability to receive a program guide via a phone line or satellite download is the big advantage over a conventional VCR, which is tough to pro- gram, not to mention getting rid of the flashing “12:00.” Using this guide feature, you can set the PVR’s built-in microprocessors to automatically record programs you want to view with a one-time setting, which instructs the machine to store the program on the hard drive. In other words, you set it and forget it. In this way TV viewing is not limited, but you can record and play back programs at your convenience. Another feature of the ReplayTV 4000, as with other machines, is its ability to skip seam- lessly through commercials. This is called commercial advance (CA), which allows a recorded program to be viewed commercial-free. It has been available on VCR units, but there is quite a difference in the way a PVR machine works. With a VCR when a commercial is PERSONAL VIDEO RECORDERS (PVRs)–TIVOs 379 detected, the VCR will go into a scan mode, which causes a short or long pause. With the ReplayTV in commercial advance, the commercials just disappear, like with magic. However, we must note that the CA feature may not always work. The commercial advance feature, when operating in the real world of video TV, is effective between 70 and 90% of the time. It seems that it will not work during the first or last 2 minutes of a program. It does do a remarkable job of taking out commercials, but it seems to vary with the types of programs that have been recorded. At times the ReplayTV PVR will show the first 2 or 3 seconds of a com- mercial break, then come back into the last 2 seconds of the commercial. At other times, the commercials will not be shown at all. It’s not 100% perfect, but it sure beats seeing all of those endless commercials. All in all the ReplayTV 4000 series consists of very good recording PVR machines. 380 DVD SYSTEM OPERATION 12 BASIC CONSUMER ELECTRONICS SERVICE AND MAINTENANCE 381 CONTENTS AT A GLANCE Introduction Service Notes or Manuals Points to Consider before Starting Circuit Boards and Solder Connections Thermal problem Large or heavy components Circuit vibration Intermittent Problems Using Electronic Equipment Flowcharts Using the simple flowchart Fuses and Circuit Breakers Notes on thermistors Circuit breaker tips Noise Spikes and Glitches Trouble, Symptom Observations Notes for audiocassette players Notes for CD players Notes for printers Introduction This chapter is devoted to tips for locating, repairing, and adjusting common problems that “crop-up” in consumer electronic products that are usually found in the home or office. Also, there are notes on some maintenance procedures that will help you keep these prod- ucts working trouble free and longer. ADJUSTMENT AND SERVICING CAUTION: 382 BASIC CONSUMER ELECTRONICS SERVICE AND MAINTENANCE Most electronic devices sold today do not have a power or isolation transformer, which means the chassis ground is connected directly to one side of the ac line voltage. This equipment is referred to as having a “hot chassis,” and touching these chassis points could cause a deadly shock. Always unplug the device before checking out a problem, such as replacing a fuse or component. The device you are working on can also be plugged into an isolation transformer; however, this is not always foolproof either. Service Notes or Manuals A service manual is a very helpful item to have when you are checking out or adjusting any electronic device. Save any of the printed information that comes with the equipment, or better yet, purchase a service manual. These can be quite helpful and may quickly solve any problem, plus give you all of the correct adjustment procedures. Some will have a sec- tion on the equipment test procedures, check outs, and any faults that may have occurred for this device. And there may be included a list of common troubles and hints on solutions to these problems. Points to Consider before Starting Let’s take a few minutes and go over a few points before you start any repairs on your electronic equipment. ■ Have a clean and well-lighted work area, with a rubber pad, and several small containers to keep any screws or small parts that you have to remove. ■ Take all of the safety precautions for working with your electronic equipment. ■ Take your time and think through what you are going to do and how. ■ Make sure you have all of the proper tools, etc. ■ Do not go any further with the repairs than what you are capable of doing. If you take equipment too far apart or make adjustments you do not understand, you may do more damage and undergo more repair cost than if you had taken it to a professional service cen- ter. A simple problem could turn into a very costly one. ■ If you are going into the circuit boards with a volt-ohm meter probe, use extreme cau- tion, as just one slip with solid-state devices can be costly or render the equipment not repairable. ■ Be very careful when using a hot soldering iron. Circuit Boards and Solder Connections A good many electronic devices develop problems, sometimes intermittent, because of poor solder connections and these can be affected by temperature changes (the problem develops after a warm-up period) or by some type of vibration that causes the device to malfunction. THERMAL PROBLEM The heating up and cooling down of the circuit board and components may cause a solder joint to fail and an intermittent condition to appear. You can try locating the problem area by flexing the board, moving various parts, or heating with a hair dryer different sections until the intermittent develops. Also, try using a cooling spray as it will serve the same pur- pose. The area you are heating and cooling when the problem occurs is where the defect is located. Also, look for any cracks in the printed circuit (PC) board. You can now try resol- dering the connections in this area that has been pinpointed. LARGE OR HEAVY COMPONENTS If your electronic equipment has some large components mounted on the PC boards, care- fully inspect or resolder all of their connections. This is a quite common problem in some electronic equipment, especially if it has been subject to lots of vibration and has been car- ried around a lot. CIRCUIT VIBRATION As stated above be on the lookout for equipment that is portable and has been subject to lots of vibration, and carefully inspect the PC boards for cracks and poor solder joints. Intermittent Problems Let’s take a look, in more detail, at some other reasons your electronic equipment may have developed an intermittent problem. An intermittent problem could be caused by an outside interference problem if the device is a TV receiver, cell phone, cordless telephone, stereo amplifier system, or AM/FM receiver. This interference could be coming in as an RF carrier over the airwaves, or transmitted over the power lines and even the telephone line coming into your home. You can try filters on the power line or telephone lines to see if they do the trick. Also, try moving the equipment to another location; if the intermittent problem goes away you know it’s an outside RF-type interference problem. INTERMITTENT PROBLEMS 383 384 BASIC CONSUMER ELECTRONICS SERVICE AND MAINTENANCE The other intermittent problem would be within the electronic device’s internal circuits. The first test is to gently tap on various parts of the case and see if the intermittent condi- tion can be duplicated. If this makes the intermittent condition show up, then you may want to remove the device’s case. Then use a small wooden dowel to press around on var- ious components and circuit boards. As noted previously, try some heat or cooling spray to make the problem appear. Always be on the lookout for “cold” defective solder joints. If there are any cables or cable connections present, flex and wiggle them and/or clean any plug-in connection. The cables themselves may be defective and need to be replaced. Transistors and ICs will also fail internally and the heat and cold treatment will usually make these components start acting up. Using Electronic Equipment Flowcharts At times you may find flowcharts along with circuit diagrams and other service informa- tion packed with your new electronic equipment. If you purchase service manuals for your devices, they will sometimes include flowcharts. When trying to determine what is caus- ing a problem in your equipment, try thinking logically how the circuits work and what are the trouble possibilities. That’s when the flowcharts can be of value because they will give you a simpler understanding of how the circuit flow throughout the device is accom- plished. It is also a good idea to make the simple checks first and think of the most probable faults that will occur. USING THE SIMPLE FLOWCHART The electronic equipment flowchart is actually a simple block diagram of the much more complicated, detailed circuitry schematic. How these blocks function, their main purpose, and how the circuits are interconnected is usually shown on these flowcharts. The blocks will indicate their subcircuit functions. After studying these blocks and their subcircuits this should help you to note various equipment failures and determine which section is likely to be at fault. As you refer to the drawing in Fig. 12-1, you will see a simple flowchart of a color TV receiver. For any type of electronic equipment, especially if the unit is dead, the power supply block is a good place to start. Check the fuses or circuit breaker and any power plugs/cords. If you have a voltmeter, then some voltage checks can pinpoint the trouble to the power supply or to another circuit block. A faulty power supply or its filter and regu- lator circuits can cause many different symptoms. Some flowcharts can be very compli- cated looking, but you can redraw them in a more simple way that you can understand. Another tip is to break down the complete device, such as the color TV flowchart in Fig. 12-1, to the one section that you are having a problem with, after the power supply is performing properly. As an example, should you have a sound problem in a TV set, you would zero in on the flowchart or block diagram of the audio circuit, shown in Fig. 12-2. After a preliminary check of the audio flowchart you should then go to the actual circuit drawing or to a more detailed subflowchart for more testing. In the detailed subflowchart you can look for the key components such as transformers, capacitors, transistors, and IC chips. The detailed flowchart in Fig. 12-3 has some of the key components identified for USING ELECTRONIC EQUIPMENT FLOWCHARTS 385 First amplifier stage Power amplifier Audio preamp Audio detector Volume control Power supply FIGURE 12-2 Flowchart of the audio section of a TV receiver that is used further testing. If your TV set has only sound trouble, and the power supply is OK, then you do not need to start checking out other flowchart blocks. Just stay with the ones that pertain to the audio circuitry, speaker wiring, and speakers. In a remote-controlled TV receiver, do not overlook a fault in the sound mute circuit, or that the TV set has actually been muted with the remote hand unit. When drawing your own flowchart, each individual capacitor or resistor will not have to be noted. The active or key components, such as transistors, ICs, and transformers, are the Tuner IF and detector SYNC Audio amplifier Vertical sweep Horizontal sweep High voltage Video CHROMA Power supply Antenna Speaker CRT Fuse AC line FIGURE 12-1 A simplified flowchart for a color TV receiver that should help pinpoint circuit problems. to track down audio problems. main concerns. Any of the other “passive” components next to the active ones will be in the same flowcircuit block. Many blocks in the flowchart can be eliminated by your process-of-elimination thinking. As an example, in a color TV receiver, if you have good sound and a perfect black-and- white picture, you start looking for a problem in the color or chroma circuits. You would not consider checking out the tuner or sound circuits. So, use your old standby, the trick of the process of elimination and logical thinking. A good flowchart, some logical thinking, and trouble symptom considerations will let you track down the defect that is causing the problem. Fuses and Circuit Breakers When a fuse or circuit breaker fails, there can be several reasons for this to occur. It may well be an ac line voltage surge, a momentary overload in the electronic device, a spike or glitch on the power line, a fuse or breaker that’s actually defective (weak), or a defect in the equipment itself. It’s OK to replace the fuse with one of the correct or an exact value as called for in the service data. Professional service technicians do this as a standard proce- dure. A replacement fuse of a lower value will keep blowing and a higher-value fuse will not give proper circuit protection and could do great circuit damage or cause a fire hazard. After you replace a fuse with one of the correct value, turn on the device and observe its operation for at least 1 hour or more. If the electronic device appears to operate properly, no burning smell or flames, then the blown fuse was probably caused by a line surge or a faulty (fatigued) fuse/weak circuit breaker. More on circuit breakers a little later in this chapter. 386 BASIC CONSUMER ELECTRONICS SERVICE AND MAINTENANCE First amp. Power amplifier Preamp Audio detector Volume control R422 Power supply F101 S201 Q401 and Q402 IC202 and Q203 IC201 Diode D101 Speaker LS 1 FIGURE 12-3 You can write in the key components on the flowchart of the stages in question, to help narrow down the location of the faulty component in the troubleshooting procedures. [...]... defective motor, or loose, dirty cable connections And don’t forget to give the machine a good cleaning GLOSSARY Use this glossary to help you better understand some of the terms used in explaining How Electronic Things Work” in these book chapters Cameras, Camcorders, Audio tape This glossary section can be used in conjunction with the video recorder, camcorder, and audio tape recorder chapters acoustic... The negative electrode of a two-terminal electronic device cell In cellular telephony, the geographic area served by one transmitter/receiver station channel An electronic communication path A channel can consist of fixed wiring or a radio link A channel has some bandwidth, depending on the type and purpose of the channel CO (Central Office) The building and electronic equipment owned and operated by... if at full volume level? 6 How does your two-way radio or cell phone work when you are near its working range end? Also, when you are getting out of its range? Is your cell phone analog or digital operation? Is your two-way radio a trunking type system? 7 Does your equipment perform differently in warm (hot) or cold weather conditions? Also, dry or damp conditions? 8 For electronic devices that are... failure-mode problems A failure of the laser is not very common and optical alignment is usually not required, unless the unit has had rough usage NOTES FOR PRINTERS The electronic portion of an ink-jet printer is usually very reliable However, you should be on the lookout for caked ink within the “service station” area, almost empty ink cartridge, and misaligned print-head contacts when you have an erratic... a fire Noise Spikes and Glitches In the real world of solid-state digital electronics, the problems of spikes and glitches can cause many problems that had very little effect on analog devices Digital circuits are very sensitive and unforgiving to noise spikes and glitches The drawing in Fig 12-4 illustrates 388 BASIC CONSUMER ELECTRONICS SERVICE AND MAINTENANCE Normal digital signal Digital pulse with... recording block diagram A diagram that shows the different stages of a system booster amplifier A separate amplifier that is connected between the main unit and the speakers in a car stereo system bridging Combining both stereo channels of the amp to produce a mono signal with almost twice the normal power rating in a car stereo system cabinet A box that contains speakers or electronic equipment capstan The... coil and cone The same principle applies to the human ear or to headphones dynamic range The ratio between the maximum signal-level range and the minimum level, expressed in decibels (dB) electronic speed control An electronic method of controlling the speed of the capstan motor electrostatic An electrostatic speaker headphone, or microphone, that uses a thin diaphragm with a voltage applied to it The... (analog-to-digital converter) An electronic device used to convert an analog voltage into a corresponding digital representation AF (audio frequencies) The frequencies that fall within the range of human hearing, typically 50 to 18,000 Hz AM (amplitude modulation) A technique of modulating a carrier sinusoid with information for transmission anode The positive electrode of a two-terminal electronic device attenuation... Finding out what’s wrong with your electronic devices can often be boiled down to observing when the equipment fails and listing other pertinent operation details A good point is to compare the equipment when it was working correctly and then when the problems or failures occur The following is a list of equipment trouble observations that you can make for various electronic devices: 1 Do the control... oscillator in the tuner, the horizontal oscillator signal (15,750 Hz) and vertical oscillator signal (60 Hz) oscilloscope A test instrument that can show exact waveforms throughout the TV circuits to help troubleshooting and locate defective components for the electronic technician PC board A subassembly of various parts, not necessarily all for one and the same function, on a phenolic or fiberglass board . good cleaning. 390 BASIC CONSUMER ELECTRONICS SERVICE AND MAINTENANCE GLOSSARY 391 Use this glossary to help you better understand some of the terms used in explaining How Electronic Things Work”. FLOWCHART The electronic equipment flowchart is actually a simple block diagram of the much more complicated, detailed circuitry schematic. How these blocks function, their main purpose, and how the. trouble free and longer. ADJUSTMENT AND SERVICING CAUTION: 382 BASIC CONSUMER ELECTRONICS SERVICE AND MAINTENANCE Most electronic devices sold today do not have a power or isolation transformer,