Question about TruTech PM1919BXA1 19 in. LCD TV
This is usually a power board or a ballast (also called the inverter). You eliminated the power board so the only remaining cause is the ballast. In most cases, this part is supplied with the LCD panel only. However, you should remove it from TV and inspect each transformer visually. Many ballasts that act in this manner have a failing transformer. You may be able to cross reference the part to find a suitable replacement part. I hope this was helpful, best wishes.
Posted on Apr 24, 2010
OK above is a generic version Service and repair manual. This is what you really need to troubleshoot and repair.
Hi, well I applaud you for wanting to have a go and try to repair you set. But PLEASE, start in the right place, Which, indeed it looks like you have, as you have already replaced the PSU, so in my mind, you are off to a good start, And as you see, you MUST start, in the right place, The power supply, FIRST, as, if, that isn't right, nothing else can be. But you simply cannot do anything without a Service Manual. In this it has everything one needs to repair the set. So, OK if it is shutting down, You need to find out "Why" it is "Shutting Down" usually, it will be an "Over Current" thing, something, is drawing too much current, and the supply senses that, and shuts down, look for something, either partially or fully shorted, if it happens after an amount of time, of working and then faulting, then it is most definitely, anyway, a "Thermal" problem, the way we "Find" problems such as this is "Freeze Spray" you use this on each component that is suspected of being the "Culprit", in the area around your drive, and you will soon,find that errant component. Now, also not every fault is a Capacitor, I see many, many people that think, that Capacitors are always the "Culprit" and replace them, because someone else had done so and it worked, Well that maybe sometimes true, Any Low Value higher voltage Electrolytics, should be replaced, "on Spec" (As soon as you see them) as we say, but most Symptoms, can, and do have many, many different "Causes" & also, now while that may be true in a few cases, a faulty Electrolytic Cap, or even, ordinary, Cap goes faulty, this is only a SYMPTOM, something has damaged those caps causing them to "Fail". One MUST always find the root "Cause", otherwise if you just treat, the SYMPTOM, the "Cause" will just make the "Symptom" come back, in short order, as the prime cause still, hasn't been fixed., usually either the PSU, has problems, or, bad circuitry, on the affected "Rail" to the Components affected. Now Capacitors hate AC ripple, or Over Voltage. Thats it. Oh.. and Heat, if these Capacitors, are too close to a Heat Source, then thats a prime cause of failure. Resistors, hardly ever go faulty,and if they do, it is generally obvious. However it doesn't hurt to check values with our Multimeter. Remember though resistors are made, with up to 20% tolerance from stated value, as such, are not too critical, unless in Timing circuits etc. Always check, the Values, of resistors, as with any other component, with the power OFF. Now Diodes especially "Zener Diode", are another thing to check, those and ordinary "Signal Diode" should always be suspect. next we have Transistors and IC's. The Transistors MUST ALL be checked to see if they have a good, "Junction" this is done, with our meter set to "Diode Test" and usually are about 0.6 to 0.7. With IC's you must check, voltage levels, or Logic Levels, going in and out, have a look at the circuit diagram, and it will tell you what they should be. It is a good idea to always measure the Power Supply voltages, see if a "Rail" is Low, that will be because some component has gone somewhat or all short circuit, to Earth, now, if the "Rail" is Higher, suspect an "Open Circuit" component, like a Diode, or Transistor. The voltages expressed in the manual are spot on, ANY variation MUST be investigated. I have been doing all this for over 30 years now, and I do indeed wish, we could have a set of "Symptoms" and be ables to say.. "Oh that;s the so-in-so and replace this" however unfortunately this although does happen, most "Symptoms" can have literally tens, of "Causes" all often "Interlinked" One simply has to do a methodical troubleshooting procedure, and always think, "are my Voltages Correct" as this is how, you Fix the problem, by making them so. Keep up the good work. If that link above doesn't furnish a Service manual, it is imperative you get one, even if you must pay for it. It will pay for itself in about 2 mins.
Posted on Apr 24, 2010
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Posted on Jan 02, 2017
SOURCE: the back light turns on
Just wondering if they were new or second hand boards you used. I would be inspecting the inverter circuit for the back-light is causing the problem for you. Short of replacing that also,I would be looking at repairing the area itself. If you have some electronics experience and the tools required...common problems you may find are
Posted on Apr 24, 2010
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