Re: LG 55LV5500-TA No picture, No sound

I agree, PANEL_CTL needs to be taken low for the 12V to be allowed to go to the T-CON board, so I am thinking the processor is not commanding the output, either due to detecting a fault or is faulty itself, this would also explain why no sound, the processor is not working at all or has decided there is a fault condition, The flash of Red then White of the Bezel LED a clue as to a fault code?

Re: LG 55LV5500-TA No picture, No sound

Here is the layout of the boards of the TV, looks fairly common to other models in other threads.
[ATTACH]160726[/ATTACH]

From the training manual for a 55LW5600 (not my model but seemed very similar) I was able to test the DRV-ON signal, when I applied the 3.5V supply to the DRV-ON connection, the TV's backlight came on.
[ATTACH]160728[/ATTACH]

Have checked Q507 and believe it is working, I took the main board out of the TV and tested it on the bench, I applied 12V to L511 and put a short across...

Re: LG 55LV5500-TA No picture, No sound

Hello Dick,

With the TV turned off, the only voltage present is the 3.5V which measures 3.551 with respect to chassis.

With the TV turned on I got the following:

Pin..........Label..........Voltage
1.........POWER-ON......3.437
2->4........24V..........24.73
3->8........GND...........0.003
9->12......3.5V...........3.541
13->15....GND...........0
16.......VSYNC-IN.......0
17,19,21...12V.........12.09
18.........DRV-ON........0.036...

Hello all,

What a useful site, so much information and knowledgeable people, it is great, wish I had found it earlier.

So I have a LG 55LV5500-TA with no picture or sound as I have seen in a few other threads for similar model TV's. I have followed the training manual posted here for a similar model and have proven the power supply is okay, and that the LEDS can be turned on by jumpering the power supply connector. What I have found is there are no volts on the fuse on the T-CON board, I pulled the main board out of the TV and tested the components that should feed...

Re: New Members - please post your introductions here

Hello All,
I'm Bevan, an electronic / radio technician from Whyalla, South Australia. I am also an Amateur Radio Operator thus the VK5BD call sign.
Regards,
Bevan