60PA6500 - Same old problem, no picture but sound

[chood2]

Hello all!

Been doing some research and I can't find anything that covers what I'm looking for, besides this:
https://www.badcaps.net/forum/showthread.php?t=18542&

I have a LG 60PA6500 that currently turns on and has no picture but sound.

I'll explain my situation. I'm a college student looking to fix this broken TV - I have resources for all the DIY I may need, from reflow soldering to oscilloscopes and infinite amount of testing equipment and supplies. This can be fixed, but I need to figure out what's wrong on it - That, I don't have much experience in.

Here's some additional information:

1. The control logic board does not flash at all - the 5V bus is getting power. The main board has a constant red light when I power it on. Can't find any information about if the logic board has no light!

2. Where are schematics? Are there none? I feel like there's gotta be some service manuals or something -- All I can find is for the main board, which I would love to have for the other boards...

3. I have replaced the left hand side (top and bottom) buffer boards, also tried per a forum/website to disconnect the Y and Z from the power supply -- no dice.

4. Measured voltages -- Everything looks good with 5V, VA, VS --

5. Obviously the fuses are all good to go... (Including ones that don't necessarily look like regular fuses)


Where to start? I'm thinking/hoping if I can just replace the control logic board it'll fix everything but that might not be the case...

[dskall]

Re: 60PA6500 - Same old problem, no picture but sound

You have stable VA,Vs. Have you tried to force test patterns?
Service manual: https://www.manualslib.com/manual/11...-60pa6500.html

[chood2]

Re: 60PA6500 - Same old problem, no picture but sound

I'm not sure how to force a test pattern! Couldn't find the exact details for this model. How do I do this?

**EDIT**
I found this:
"OK, on the CTRL board you can see a pair of holes on the bottom right hand of the board marked EXT AUTO GEN.

Turn the TV power off (unplug the set)
Place a wire link between these holes
Disconnect the LVDS cable between the main board and control board
Plug the TV in...do the test patterns cycle continuously?"

Will test and come back.

[tw2005]

Re: 60PA6500 - Same old problem, no picture but sound

good idea, I'd start there

[chood2]

Re: 60PA6500 - Same old problem, no picture but sound

good idea, I'd start there

You have stable VA,Vs. Have you tried to force test patterns?
Service manual: https://www.manualslib.com/manual/11...-60pa6500.html

Hi all, went ahead and tried to connect the EXT pins, disconnect the main blue connector (as shown on the right), and see if I get a test pattern. No dice.

Thoughts?

Click for Picture

[chood2]

Re: 60PA6500 - Same old problem, no picture but sound

What might be some standard FETs or areas that go bad?