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LG 32lg710H won't turn on

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    LG 32lg710H won't turn on

    My wife works at a hotel and brought home a TV they were going to throw out, thinking I'd be able to use it for my business if I could get it working. Plugged in, the red standby light would come on the front panel, but it was completely unresponsive.
    Opened it up, did all the usual checks and found several problems. The first thing I noticed was that the Reset and Update switches were horribly mangled. They looked like someone had been jamming them REALLY HARD with a screwdriver or something. The reset switch was in a state that it was no longer possible for the two sides to make physical contact, and the update switch was twisted so that it was permanently shorted. I pulled the tops off, put some through hole tac switches over the tops, soldered them on and tested for function. They now work fine.
    The second problem I noticed was of the two caps on the inverter, one was vented and the other had a broken leg. Just a guess, but I think the one with the broken leg threw the circuit too far out of whack and put too much strain on the other, which made the TV stop working. I'm guessing it was after that that someone went after the reset button with a torture device. I tested the voltages and fuses of the PSU board and everything seemed fine there, so I ordered new caps for the inverter and installed them when they arrived.

    So I've made progress, but it still won't power on. Now, instead of a solid red light all the time (which I can still simulate by holding the update button), when you try to power it on the red light turns blue and flashes 46 times. Then it does one of two things based on some unknown combination of how recently I've hit the reset button and how long it's been plugged in or unplugged. It will either change the status light back to red, at which point hitting the power button will restart the cycle, or it will stay solid blue. While solid blue, I can use the input/source/channel/volume buttons and the status light blinks for each press, until after a while (15 sec - several min) it will turn back to red.

    I've never heard any relays click on. I've checked with a flashlight to see if there's any image and just no backlight, but there is none. There is no audio. I've tried with and without a source input (AppleTV to HDMI 1). To me it seems like probably the processor is trying to start the thing up, goes through its checks, finds that something is not right and shuts down. I'd like to test the inverter to see if I can get the backlights to come on, but I'm not sure how to send the BL_ON signal. I'm assuming it's probably either sending the pin high or low, but I don't want to start jumping wires without knowing for sure. And then from there, I'm not sure where to turn next. It does appear as though it may have been dropped at some point, which is why I want to test CCFL first. There are no cracks anywhere in the screen, but the outer plastic was overlapped the wrong direction in one area, and on that corner inside the aluminum frame is slightly warped.

    Any thoughts or advice would be most appreciated.
    Successful repairs: Half a dozen monitors, 2 TVs, computer speakers, car amps, electronic piano, and a handful of computers.
    Unsuccessful repairs: Every electronic toy I got until age 14, a Drobo, Powerbook 145b, a couple SCSI disk drives, and on occasion my dignity.

    #2
    Re: LG 32lg710H won't turn on

    Pictures of boards etc??

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      #3
      Re: LG 32lg710H won't turn on

      Unplug the main board from the PSU, leave the inverter with the backlights hooked up.
      Take two 1k Ohm resistors and jump STBY voltage to PSon, take the other resistor and jump STBY voltage to BLon. Plug the PSU in and all the voltage rails on the PSU should be up and the backlight on.

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