Television Troubleshooting And Repair PdfBy Roy C. In and pdf 01.05.2021 at 07:15 9 min read
File Name: television troubleshooting and repair .zip
- Training Manual - Lcd Tv Repair
- Notes on the Troubleshooting and Repair of Television Sets
- LCD TV Repair Guide Handbook_140211_v1
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Training Manual - Lcd Tv Repair
Thank you for interesting in our services. We are a non-profit group that run this website to share documents. We need your help to maintenance this website. Please help us to share our service with your friends. Share Embed Donate. If the lamp works, then the problem is the TV. It not, the outlet is defective or the fuse is blown or the circuit breaker is tripped.
There is another very simple explanation that is sometimes overlooked: This is a switched outlet. You always wondered what that wall switch was for that didn't seem to do anything and you flipped randomly Well, now you know! If you can get a response, even momentarily, the cord likely has broken wires internally. Beyond these basic causes, troubleshooting will be needed inside the set to determine what is defective.
Also see the section: "Intermittently dead set bad cordset". Don't overlook these really simple things when troubleshooting your vacuum cleaner - or fancy electronic equipment! If the problem is at the plug end, cut off the old plug a couple of inches beyond the problem area and replace just he plug. If the problem is at the appliance end, an entire new cordset is best though you can probably cut out the bad section and solder what remains directly to the mainboard.
In either case, observe the polarity of the cord wires - they will be marked in some way with a ridge or stripe. It is important that the new plug be of the same type polarized usually and that the cord is wired the same way. This can usually be remedied by using a pointed tool like an awl or utility knife to spread apart the pair of leaves often used to form each prong of the plug.
If the prongs are made of solid metal, it may be possible to spread them apart - widen the space between them. Alternatively, get a 3 to 2 prong adapter just to use as an intermediate connector. Spread the leaves of its prongs. However, a new outlet is best. As you flex the cord, it is also stressing the attachment to the mainboard and affecting some marginal solder joints. It is important to deal with these symptoms as soon as possible as erratic power cycling can lead to much more serious and expensive problems down the road.
There could possibly be a bad pullup resistor or something of that sort - but is it worth the effort to locate? Why not just continue to use the remote? There is no reason to suspect that it will develop similar symptoms. However, there is some risk that if the button is dirty, you may find the TV coming on at random times in the middle of the night of course!
I think I have an older Sylvania that does that sort of thing - don't really know as I never use the power button on the set! If power is controlled by a hard switch - a pull or click knob, or mechanical push-push switch and this has become erratic due to worn contacts, replacements are available but often only directly from the original manufacturer to physically fit and where applicable have the volume or other controls built in.
As an alternative, consider mounting a small toggle switch on the side of the cabinet to substitute for the broken switch.
This will almost certainly be easier and cheaper - and quite possibly, more reliable. Horizontal output transistor. Power supply regulator if there is one. Power supply chopper switchmode transistor if there is one. Diode s in main bridge Main filter capacitor s. You should be able to eliminate these one by one. Unplug the degauss coil as this will show up as a low resistance. First, measure across the input to the main power rectifiers - it should not be that low. A reading of only a few ohms may mean a shorted rectifier or two or a shorted Posistor.
It includes a line operated heater disk which often shorts out and a PTC thermister to control current to the degauss coil. Remove the posistor and try power. If the monitor now works, obtain a replacement but in the meantime you just won't have the automatic degauss. If these test good, use an ohmmeter with the set unplugged to measure the horizontal output transistor. Even better to remove it and measure it. If any readings are under 5 ohms, the transistor is bad.
The parts sources listed at the end of this document will have suitable replacements. If the HOT tests bad, try powering the set first with your light bulb and if it just flashes once when the capacitor is charging, then put a fuse in and try it.
The fuse should not blow with the transistor removed. Of course, not much else will work either. If it tests good, power the set without the transistor and see what happens. If the fuse does not blow, then with the good transistor assuming it is not failing under load , it would mean that there is some problem with the driving circuits possibly or with the feedback from the voltages derived from the horizontal not regulating properly.
There may be a separate transistor that does the low voltage regulation or a separate regulator IC. There is a chance that one of these may be bad. If it is a simple transistor, the same ohmmeter check should be performed. If none of this proves fruitful, it may be time to try to locate a schematic. A blown fuse is a very common type of fault due to poor design very often triggered by power surges due to outages or lightning storms. However, the most likely parts to short are easily tested, usually in-circuit, with an ohmmeter and then easily removed to confirm.
One possibility is a drive problem. The messed up sync resulting from swtiching channels, or changing input connections might be resulting in an excessively long scan time for just one scan line. However, this may be enough to cause a current spike in the horizontal output circuit or an excessive voltage spike on the collector of the horizontal output transistor. Normally, the HOT current ramps up during scan. During flyback, the current is turned off.
This current is normally limited and the voltage spike on the collector of the HOT is also limited by the snubber capacitors to a safe value. If scan time is too long, current continues to increase. At some point, the flyback core saturates and current goes way up. In addition, the voltage spike will be much higher - perhaps destructively so. Troubleshooting these sorts of problems is going to be tough. However, most of the time, damage is minimal or at least easily repaired. With a direct hit, you may not recognize what is left of it!
Ideally, electronic equipment should be unplugged both AC line and phone line! Modern TVs, VCRs, microwave ovens, and even stereo equipment is particularly susceptible to lightning and surge damage because some parts of the circuitry are always alive and therefore have a connection to the AC line.
Telephones, modems, and faxes are directly connected to the phone lines. Better designs include filtering and surge suppression components built in. With a near-miss, the only thing that may happen is for the internal fuse to blow or for the microcontroller to go bonkers and just require power cycling.
There is no possible protection against a direct strike. However, devices with power switches that totally break the line connection are more robust since it takes much more voltage to jump the gap in the switch than to fry electronic parts. Monitors and TVs may also have their CRTs magnetized due to the electromagnetic fields associated with a lightning strike - similar but on a smaller scale to the EMP of a nuclear detonation.
Was the TV operating or on standby at the time? If it was switched off using an actual power switch not a logic pushbutton or the remote control , then either a component in front of the switch has blown, the surge was enough to jump the gap between the switch contacts, or it was just a coincidence yeh, right.
If the TV was operating or on standby or has no actual power switch, then a number of parts could be fried. So it is possible that all that is wrong is that the line fuse has blown. Remove the cover unplug it first! If you find a blown fuse, remove it and measure across the in-board side of fuse holder and the other should be the neutral side of the line.
The ohmmeter reading should be fairly high - well certainly not less than ohms - in at least one direction. You may need to unplug the degaussing coil to get a reasonable reading as its resistance may be 25 or 30 ohms. If the reading is really low, there are other problems. If the resistance checks out, replace the fuse and try powering the TV.
There will be 3 possibilities: 1. It will work fine, problem solved. It will immediately blow the fuse. This means there is at least one component shorted - possibilities include an MOV, line rectifiers, main filter cap, regulator transistor, horizontal output transistor, etc. You will need to check with your ohmmeter for shorted semiconductors.
Remove any that are suspect and see of the fuse now survives use the series light bulb to cut your losses - see the section: "The series light bulb trick".
It will not work properly or appear dead. This could mean there are open fusable resistors other defective parts in the power supply or elsewhere. In this case further testing will be required and at some point you may need the schematic. If the reading is very low or the fuse blows again, see the section: "TV blows fuse".
Notes on the Troubleshooting and Repair of Television Sets
We purchase our own TVs and put them under the same test bench, so that you can compare the results easily. No cherry-picked units sent by brands. These are some of the most common issues on TVs we are asked about, along with the likely solutions. Please take a look and see if your issue is addressed here, and whether the recommended fixes work, before submitting a question to us. Try the first listed step before moving on to any others.
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LCD TV Repair Guide Handbook_140211_v1
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Guides and support for various television TV brands and styles. LG 32CS Vizio Television.
From replacing a Power Supply circuit board, a T-Con circuit board, or simply securing a loose ribbon cable connection, these TV repair manuals will help you to fix your TV yourself. Please find your TV brand by using the list of TV manufacturers below. When troubleshooting your TV you will need to use schematics and diagrams to find the problem.
Отключить. Черт побери, немедленно отключить. Мидж появилась в дверях со свежей распечаткой в руке. - Директор, Стратмору не удается отключить ТРАНСТЕКСТ. - Что?! - хором вскричали Бринкерхофф и Фонтейн.
В задней части церкви между скамьями продвигался человек, стараясь держаться в тени.