If the solutions to your problems have not been covered in this document, you still have some options other than surrendering your TV to the local service center or the dumpster. Also see the related document: "Troubleshooting and Repair of Consumer Electronics Equipment". Manufacturer's service literature: Service manuals are available for a great deal of consumer electronics. Once you have exhausted the obvious possibilities, the cost may be well worth it. Depending on the type of equipment, these can range in price from $10-50 or more. Some are more useful than others. However, not all include the schematics so if you are hoping to repair an electronic problem try to check before buying. Inside cover of the equipment: TVs often have some kind of circuit diagram pasted inside the back cover. In the old days, this was a complete schematic. Now, if one exists at all, it just shows part numbers and location for key components - still very useful. Some TVs - as late as 10 years ago, maybe even now - included a complete schematic with the product information and owner's manual. I have a 1984 Mitsubishi which has this. It is, however, the exception rather than the rule anymore. Sams' Photofacts (http://www.hwsams.com/): These have been published for over 45 years (I don't know for how long but I have Sams' for a 1949 portable (3 inch) Pilot TV - about as portable as an office typewriter (if you remember what one of those was like) and are generally the best most consistent source of service info for TVs (nearly every model that has ever been sold), radios, some VCRs and other consumer electronics. For TV servicing, they are indispensable. There are some Computerfacts but the number of these is very limited. The VCRfacts are also somewhat limited and the newer ones tend to have strictly (obvious) mechanical information. Sams' Photofacts are often available (for photocopy costs) from you local large public library which may subscribe to the complete series. If not, a large electronic distributor can order the selected folder for you. One advantage of the Sams' info is that it is compiled in a very consistent format so that once you are familiar with one model TV, it is easy to transfer that knowledge to any other. They provide waveforms at key locations and DC voltage measurements almost everywhere. Additional info such as IC pin to ground and coil resistances are often provided as well. The manufacturer's service manuals are generally not nearly as complete. (BTW, I have no connection with Howard Sams.) Elsewhere around the world, libraries may also have Sams' or other service information: (From: Chris Laudan (firstname.lastname@example.org)). This is true here in UK too, though not Sams photofacts, just schematics issued by manufacturers. Go to the reference library and ask for Video and TV service manuals, most main libraries carry a good selection. (From: Michael Covington (email@example.com)). Concerning Sams' Photofacts, here is a bit of history that seems to be very little known: The name "Sams" is not an acronym, nor is it "Sam." It's the last name of Howard W. Sams, who founded the publishing company. Accordingly, they are "Sams' Photofacts" rather than any of various other spellings that we often see on the net. And they're a great product. Apparently "Howard W. Sams & Co., Indianapolis, Indiana" is a sufficient address to reach them. So is 1-800-GAT-SAMS.
Try your large public library for Sams' photofacts. I found a 3" TV of from around 1948 at a yard sale. There was no problem finding a complete set of Sams' service information including full schematics, parts list (of course, finding suitable parts like tubes in the 1990s may be a bit more difficult than when this set was new!), troubleshooting procedures, etc. Someday, I may even get around to fixing it. All the paper capacitors are leaky (for starters). BTW, the case for this 3" TV is about 18" x 10" x 15" and it includes a handy option: a 6 inch semispherical water filled magnifier. The CRT is an oscilloscope tube. Not your modern portable!
On newer TVs, the chassis number may be printed on the mainboard. (From: "Clifton T. Sharp, Jr."
Somewhere on the chassis there may be an inked chassis number; an example for one color set was TS-914. A chassis number will at least get you some service information, and should be all you need unless you plan to try to get cabinet parts for it (chortle guffaw titter). Number should be findable on the back of the chassis (i.e. where the pots are mounted through the chassis).
Here are contact numbers for some TV manufacturers: Curtis Mathis 1-800-949-4999 Steve Long Mitsubishi 1-800-552-8324 NAP 1-900-896-8324 Zenith 1-800-874-1930 ext 1065 or 1066 1-800-856-0981 1-312-745-5154 Sanyo 1-800-877-5032 Panasonic 1-201-348-7957 1-201-348-7958 1-201-392-6961 1-201-392-6992
Many manufacturers are now providing extensive information via the World Wide Web. The answer to you question may be a mouse click away. Perform a net search or just try to guess the manufacturer's home page address. The most obvious is often correct. It will usually be of the form "http://www.xxx.com" where xxx is the manufacturers' name, abbreviation, or acronym. For example, Hewlett Packard is hp, Sun Microsystems is sun, Motorola is, you guessed it, motorola. Electronic parts manufacturers often have detailed datasheets for their product offerings. Tandy (Radio Shack) has a nice web resource and fax-back service. This is mostly for their equipment but some of it applies to other brands and there are diagrams which may be useful for other manufacturers' VCRs, TVs, CD players, camcorders, remote controls, and other devices. http://support.tandy.com/ (Tandy homepage) http://support.tandy.com/video.html (Video products) http://support.tandy.com/support_video/2846.htm (TVs) In addition to Tandy products, there is at least one Sony model. Furthermore, since Tandy does not manufacture its own TV sets - they are other brands with Realistic, Optimus, or other Radio Shack logos - your model may actually be covered. It may just take a little searching to find it. The one below is specifically for the Sony KV-F29 but I assume it applies to other Sony models as well. It provides a source of technical service information and includes Sony KV-F29 related Service Bulletins: * http://www.healey.com.au/~nu-lifetv/tech/kvf/
I have found one of the most useful single sources for general information on semiconductors to be the ECG Semiconductors Master Replacement Guide, about $6 from your local Philips distributor. STK, NTE, and others have similar manuals. The ECG manual will enable you to look up U.S., foreign, and manufacturer 'house' numbers and identify device type, pinout, and other information. Note that I am not necessarily recommending using ECG (or other generic) replacements if the original replacements are (1) readily available and (2) reasonably priced. However, the cross reference can save countless hours searching through databooks or contacting the manufacturers. Even if you have a wall of databooks, this source is invaluable. A couple of caveats: (1) ECG crosses have been known to be incorrect - the specifications of the ECG replacement part were inferior to the original. (2) Don't assume that the specifications provided for the ECG part are identical to the original - they may be better in some ways. Thus, using the ECG to determine the specifications of the parts in your junk bin can be risky. Other cross reference guides are available from the parts source listed in the section: "Repair parts sources".
Some good sources for technology information: * Basic Theory of Colour Television Philips Ask for this book from your local technical bookstore. * Basic Television & Video Systems, 5th ed. Bernard Grob McGraw Hill For a technical reference on the various flavours of NTSC, PAL, and SECAM used around the world, I suggest: * Recommendations and reports of the CCIR volume XI, Part 1 Available from Omnicom, 115 Park St. S.E. Vienna, VA 22180 (703)281-1135 It following book is for PAL TV-standard specifications: * Colour Television (With particular refererence to PAL) G.N. Patchett. Norman Price (Publishers) Ltd. It has three heavyweight chapters describing NTSC/PAL/SECAM and has a decent amount of math content. The following is more directed toward digital video but may still contain some information useful for understanding analog TV technology: * Video demystified: A handbook for the digital engineer Keith Jack Brooktree Corporation, 1993 ISBN 1-878707-09-4 There don't seem to be nearly as many TV repair books for modern solid state TVs as I recall for old tube sets. Here are a couple which you may find (or its predecessor) at your local public library (621.384 if you library is numbered that way) or a technical book store. MCM Electronics has the Davidson as well. * Troubleshooting and Repairing Solid State TVs Homer L. Davidson 2nd Edition, 1992 (The 1st edition is also useful) TAB Books, Inc. Blue Ridge Summit, PA 17214 * Basic Television Principles & Servicing Bernard Grob The following is a recent publication: * Troubleshooting and Repair Guide to TV PROMPT Publications (Howard W. Sams), (800) 428-7267. ISBN #0-7906-1077-9, $29.95. From the advertising blurb for this book: "This book, 300 pages of detailed photos, schematic diagrams, and text explains in easy to understand language how TV works, how to troubleshoot problems, and advice on how to fix them. The Howard W. Sams Troubleshooting and Repair Guide to TV is the perfect reference book for technicians, instructional guide for students and hobbyists."
Only a few manufacturers actually produce the vast majority of TVs. For example, Radio Shack, Magnavox, and Emerson do not make their own TVs (I can tell you are not really surprised!). How do you determine the actual manufacturer? For most types of consumer electronics equipment, there is something called an 'FCC ID' or 'FCC number'. Any type of equipment that may produce RF interference or be affected by this is required to be registered with the FCC. This number can be used to identify the actual manufacturer of the equipment. A cross reference and other links can be found at: http://www.repairfaq.org/REPAIR/F_FCC_ID.html
The question often arises: If I cannot obtain an exact replacement or if I have a monitor, TV, or other equipment carcass gathering dust, can I substitute a part that is not a precise match? Sometimes, this is simply desired to confirm a diagnosis and avoid the risk of ordering an expensive replacement and/or having to wait until it arrives. For safety related items, the answer is generally NO - an exact replacement part is needed to maintain the specifications within acceptable limits with respect to line isolation, X-ray protection and to minimize fire hazards. Typical parts of this type include flameproof resistors, some types of capacitors, and specific parts dealing with CRT high voltage regulation. However, during testing, it is usually acceptable to substitute electrically equivalent parts on a temporary basis. For example, an ordinary 1 ohm resistor can be substituted for an open 1 ohm flameproof resistor to determine if there are other problems in the horizontal deflection circuits before placing an order - as long as you don't get lazy and neglect to install the proper type before buttoning up the monitor or TV. For other components, whether a not quite identical substitute will work reliably or at all depends on many factors. Some deflection circuits are so carefully matched to a specific horizontal output transistor that no substitute will be reliable. Here are some guidelines: 1. Fuses - exact same current rating and at least equal voltage rating. I have often soldered a normal 3AG size fuse onto a smaller blown 20 mm long fuse as a substitute. 2. Resistors, capacitors, inductors, diodes, switches, potentiometers, LEDs, and other common parts - except for those specifically marked as safety-critical - substitution as long as the replacement part fits and specifications should be fine. It is best to use the same type - metal film resistor, for example. But for testing, even this is not a hard and fast rule and a carbon resistor should work just fine. 3. Rectifiers - many are of these are high efficiency and/or fast recovery types. Replacements should have at equal or better PRV, Imax, and Tr specifications. 4. Posistors - many of these are similar. Unfortunately, the markings on the devices are generally pretty useless in determining their ratings. Note, however, that the prices for replacement posistors may be quite reasonable from the original manufacturer so it may not make sense to take the risk of using an unknown part. (From: Stefan Huebner (Stefan.Huebner@rookie.antar.com)). In most cases you can use a standard 3-terminal-device, the resistance of the temperature dependent resistors in it are nearly identical. Here is a list of possible replacement devices: 380000-01, 24340521, 2199-603-1201, 163-024A, 163-035A, CO2200-N66, C8ROH, QX265P05503, 32112026, 4822-A1-11240148, 02199-003-120, 15-08-001A, 5391560067, F400001. 5. Transistors and thyristors (except HOTs and SMPS choppers) - substitutes will generally work as long as their specifications meet or exceed those of the original. For testing, it is usually OK to use types that do not quite meet all of these as long as the breakdown voltage and maximum current specifications are not exceeded. However, performance may not be quite as good. For power types, make sure to use a heatsink. Also see the section: "Replacement power transistors while testing". 6. Horizontal output (or SMPS) transistors - exact replacement is generally best but except for very high performance monitors, generic HOTs that have specifications that are at least as good will work in many cases. Make sure the replacement transistor has an internal damper diode if the original had one. For testing with a series light bulb, even a transistor that doesn't quite meet specifications should work well enough (and not blow up) to enable you to determine what else may be faulty. The most critical parameters are Vceo/Vcbo, Ic, and Hfe which should all be at least equal to the original transistor. I have often used by favorite BU208D as a temporary substitute for other HOTs and SMPS (chopper) transistors. Make sure you use a heatsink and thermal grease in any case - even if you have to hang the assembly by a cable tie to make it fit. For that matter, you can usually substitute a similar HOT with the D suffix instead of the A (or no) suffix. These have a built-in damper diode and two in parallel (the external one) will not hurt (or remove it). Naturally, the reverse is not true since a damper diode IS essential and the HOT will probably not last beyond the click of the power relay without one! For an explanation of what the damper diode does, see: * http://www.repairfaq.org/REPAIR/sam_test/F_deflfaq.html On SVGA monitors, there will likely be additional circuitry between the HOT and the damper so this trick doesn't work for them. However, using an HOT with much better specs may actually result in early failure due to excessive heating from insufficient and/or suboptimal base drive. See the document: "TV and Monitor Deflections Systems" for more info. 7. Deflection yokes - in the old days, particularly for B/W TVs, all of these were quite similar. It was common to just swap with one that fit physically and at most need to adjust or change a width coil. With color TVs and high performance multiscan monitors, this is no longer the case. Sometimes it will work but other times the power supply won't even be able to come up as a result of the impedance mismatch due to different coils and pole piece configurations. In addition, there may be other geometry correction coils associated with the yoke that could differ substantially. However, if you are really determined, see the section: "Swapping of deflection yokes". Also see the section: "Replacement power transistors while testing". 8. Standby power transformer - this most likely only has a single secondary so locating a standard UL approved (for safety reasons) power transformer with the same output voltage should not be difficult. Check the service manual or the Sams' Photofact for the set to determine the required output voltage and if a centertap is needed. Current should be quite low. 9. CRTs - aside from the issues of physical size and mounting, many factors need to be considered. These include deflection angle, neck diameter, base pinout, focus and screen voltage requirements, purity and convergence magnets, etc. Color CRT replacement is rarely worth the effort in any case but trying to substitute a different CRT is asking for frustration. For monochrome CRTs, there is less variation and this may be worth a try. 10. The following are usually custom parts and substitution of something from your junk box is unlikely to be successful even for testing: flyback (LOPT) and SMPS transformers, interstage coils or transformers, microcontrollers, and other custom programmed chips.
You will nearly always find one of two types of horizontal output transistors in TVs and monitors: * Metal can - TO3 package: _ / O \ View from bottom (pin side) / o o \ ( B E ) B = Base, E = Emitter, C = Collector \ / \ O / C The metal case is the Collector. * Plastic tab - TO3Pn (n = several suffixes) package: _____ / \ | O | View from front (label side) | | | | B = Base, E = Emitter, C = Collector |_______| | | | If there is an exposed metal tab, this is the | | | Collector as well. B C E Some other transistor types use the same pinout (TO66 for metal can, TO218 and TO220 for plastic tab) but not all. However, for horizontal output transistors, these pinouts shouuld be valid. Note that those with a built in damper diode may read around 50 ohms between B and E (near 0 on the diode test range) - this is normal as long as the resistance is not really low like under 10 ohms.
Well, it is usually the LARGEST transistor in the set near the LARGEST transformer in the set (flyback - the thing with the FAT red wire connecting to the picture tube) on the LARGEST heat sink in the set. Got that? :-) Or, in the good old days.... (From: Don Wall (firstname.lastname@example.org)). Sure, it's usually the largest tube in the set, has a top cap, runs very hot, and is often a 6BQ6G or some such. (tongue firmly in cheek) Actually, back in the days of yore, the Horizontal Output Tube was frequently referred to as the HOT; guess some things don't change!
During testing of horizontal deflection circuits or switchmode power supplies, particularly where the original failure resulted in the death of the HOT or chopper, overstress on replacement transistors is always a possibility if all defective components have not be identified. Therefore, using a part with better specifications may save you in the long run by reducing the number of expensive blown parts. Once all other problems have been located and repaired, the proper part can be installed. However, this is not always going to work. In a TV and especially a high performance monitor, the HOT may be closely matched to the drive and output components of the deflection circuits. Putting in one with higher Vce, I, or P specifications may result in overheating and failure due to lower Hfe. Where possible, a series load like a light bulb can be used limit the maximum current to the device and will allow you to power the equipment while checking for other faults. Some designs, unfortunately, will not start up under these conditions. In such cases, substituting a 'better' device may be the best choice for testing. (From: Glenn Allen (email@example.com)). I been repairing SMPS of all types but when I started on those using MOSFETs I was blowning a few of them when replaced because something else was faulty. Ever since I have been using a BUZ355 on a heat sink I haven't blown it. It is rated at 800 V, 6 A, and 220 W. it is a TO218 case bigger than a T0220. It seems the higher ratings allows you to do repair where as a something like a 2SK1117 or MTP6N60 will just blow.
The following is useful both to confirm that a substitute replacement HOT is suitable and that no other circuit problems are still present. However, single scan line anomalies (particularly when changing channels and/or where reception is poor with a TV or when switching scan rates and/or when no or incorrect sync is present with a monitor) resulting in excessive voltage across the HOT and instant failure are still possible and will not result in an HOT running excessively hot. (From: Raymond Carlsen (firstname.lastname@example.org)). After installing a replacement HOT in a TV set or monitor, I like to check the temperature for awhile to make sure the substitute is a good match and that there are no other problems such as a weak H drive signal. The input current is just not a good enough indicator. I have been using a WCF (well calibrated finger) for years. For me, the rule of thumb, quite literally, is: if you can not hold your finger on it, it's running too hot, and will probably fail prematurely. Touching the case of the transistor or heat sink is tricky.... Metal case transistors will be connected to the collector and have a healthy pulse (>1,200 V peak!) and even with plastic case tab transistors, the tab will be at this potential. It is best to do this only after the power is off and the B+ has discharged. In addition, the HOT may be hot enough to burn you. A better method is the use of an indoor/outdoor thermometer. I bought one recently from Radio Shack for about $15 (63-1009). It has a plastic 'probe' on the end of a 10' cable as the outdoor sensor. With a large alligator clip, I just clamp the sensor to the heat sink near the transistor and set up the digital display near the TV set to monitor the temperature. The last TV I used it on was a 27" Sanyo that had a shorted H. output and an open B+ resistor. Replacement parts brought the set back to life and the flyback pulse looked OK, but the transistor was getting hot within 5 minutes... up to 130 degrees before I shut it down and started looking for the cause. I found a 1 uF 160 volt cap in the driver circuit that was open. After replacing the cap, I fired up the set again and monitored the heat sink as before. This time, the temperature slowly rose to about 115 degrees and stayed there. I ran the set all day and noticed little variation in the measurement. Test equipment doesn't have to cost a fortune.
Should you need to remove the deflection yoke on a color CRT, some basic considerations are advised both to minimize the needed purity and convergence adjustments after replacement as well as to prevent an unfortunate accident. The position and orientation of the yoke (including pitch and yaw) and magnet assembly (purity and static convergence rings, if used) are critical. Use paint or White-Out(tm) to put a stripe across all of the magnet rings so you will know their exact positions should they accidentally shift later. If there are rubber wedges between the yoke and the funnel of the tube, assure that they are secure. Tape them to be doubly sure as adhesive on old tape dries up with age and heat and becomes useless. This will avoid the need for unecessary dynamic convergence adjustments after reassembly. The neck is the most fragile part of the CRT so do not apply any serious side-ways force and take care not to bend any of the pins when removing and replacing the CRT socket. The yoke and purity/static convergence assemblies will be clamped and possibly glued as well. However, the adhesive will probably be easily accessible - big globs of stuff like hot melt glue and/or RTV silicone. Carefully free the adhesive from the glass neck of the CRT. Loosen the clamps and gently wiggle the magnets and yoke off the neck. They may appear stuck from age and heat but should yield with gently persuasion. Once the yoke is replaced, some fine adjustments of the picture rotation, purity, and static and dynamic convergence may be needed but hopefully with your most excellent diagrams, these will be minimal. Similar comments apply for monochrome CRTs but there are far fewer issues as the yoke is positioned firmly against the funnel of the CRT and rotation and centering are usually the only adjustments. However, there may be magnets located on swivels or glued to strategic locations on the CRT envelope to correct for geometric distortion.
This should work with identical TVs or monitors. Your mileage will vary if you are attempting a swap between monitors with similar specifications. Chances of success for monitors with widely different screen sizes or scan rate specifications is close to zero. One indication of compatibility problems would be major differences in resistance readings for the corresponding yoke windings, CRT HV and other bias levels, etc. Before you do the transplant, see the section: "Removing and replacing the deflection yoke" for procedures and precautions to minimize problems in realignment. Make a precise diagram of everything you do. Keep the purity/static convergence magnet assembly with the original CRT if possible and install it in the same or as nearly the same position as possible when you replace it. Once you are sure of the connections, power it up carefully - there is no assurance that your yokes are compatible. A yoke with a much lower resistance or inductance than the original may overstress components in the power supply. You will then need to go through all the adjustments starting with purity and convergence.
Given the problems of just replacing a CRT with an identical new one, it isn't surprising that attempting to substitute a CRT which is not the same type will result in difficulties - to say the least. Obviously, the closer in size, scan rate (for monitors), and deflection angle, the more likely the chances of success. Where the alternative is to junk the TV or monitor, it may be worth a shot - and you may get lucky! It may be best to transfer as much as possible with the CRT - yoke and purity and convergence magnets. The connectors to the yoke may need to be changed but this may be the least of your problems. Difference in yoke impedance and other characteristics may result in anything from incorrect size to a truly spectacular melt-down! The latter is much more likely with SVGA monitors compared to similar size/deflection angle TVs. Where the neck size is the same, the yoke can be moved from one CRT to the other but you will have to do a complete purity and convergence set up and even then you may have uncorrectable convergence errors. See the section: "Swapping of deflection yokes". (From: J. G. Simpson (email@example.com)). Monitors are generally designed by choosing a CRT, then the EHT, then designing a yoke to scan the CRT, then designing a driver circuit to drive the yoke. In a CRT test lab it's common to have variable supplies for EHT and other voltages, a small selection of yokes, and variable amplitude drive circuits. EHT affects scan sensitivity, brightness, spot size. You can't get high brightness and small spot size on a large monitor with 3 KV of EHT. Virtually every variable has some effect on convergence. Spot size is important, in as much as you want most of it on the phosphor and not the shadow mask. Provided the neck size is the same you can swap tubes in yokes but don't expect it to work very well. Different tube manufacturers may use radically different gun structures. A given yoke and its driver may give underscan or overscan and it's pretty well certain that convergence will be way off. The military spends a small fortune on trying to get the drop into the yoke and it flies with no adjustment or convergence CRT. For the rest of us swapping a CRT is a pain in the butt.
Larger components like electrolytic capacitors are often secured to the circuit board with some sort of adhesive. Originally, it is white and inert. However, with heat and age, some types decay to a brown, conductive and/or corrosive material which can cause all sorts of problems including the creation of high leakage paths or dead shorts and eating away at nearby wiring traces. The bottom line: Most of the time, this stuff serves no essential purpose anyhow and should be removed. A non-corrosive RTV or hot-melt glue can be used in its place if structural support is needed.
For general electronic components like resistors and capacitors, most electronics distributors will have a sufficient variety at reasonable cost. Even Radio Shack can be considered in a pinch. However, for consumer electronics equipment repairs, places like Digikey, Allied, and Newark do not have the a variety of Japanese semiconductors like ICs and transistors or any components like flyback transformers or degauss Posistors. The following are good sources for consumer electronics replacement parts, especially for VCRs, TVs, and other audio and video equipment: * MCM Electronics (VCR parts, Japanese semiconductors, U.S. Voice: 1-800-543-4330. tools, test equipment, audio, consumer U.S. Fax: 1-513-434-6959. electronics including microwave oven parts and electric range elements, etc.) Web: http://www.mcmelectronics.com/ * Dalbani (Excellent Japanese semiconductor source, U.S. Voice: 1-800-325-2264. VCR parts, other consumer electronics, U.S. Fax: 1-305-594-6588. car stereo, CATV). Int. Voice: 1-305-716-0947. Int. Fax: 1-305-716-9719. Web: http://www.dalbani.com/ * Premium Parts (Very complete VCR parts, some tools, U.S. Voice: 1-800-558-9572. adapter cables, other replacement parts.) U.S. Fax: 1-800-887-2727. * Computer Component Source (Mostly computer monitor replacement parts, U.S. Voice: 1-800-356-1227. also, some electronic components including U.S. Fax: 1-800-926-2062. semiconductors.) Int. Voice: 1-516-496-8780. Int. Fax: 1-516-496-8784. For those hard-to-find or overpriced TV replacement boards, modules, or other parts, try: * PTS Electronics Corporation. - Bloomington, Indiana (National Headquarters): 1-800-844-7871 - Arvada, Colorado: 1-800-331-3219 - Tustin, California: 1-800-380-2521 Email: firstname.lastname@example.org Web: http://www.ptscorp.com/. Also see the documents: "Troubleshooting of Consumer Electronic Equipment" and "Electronics Mail Order List" for additional parts sources.There is no Next. THE END
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