LG 55LW5700 Service Manual

[budm]

Re: LG 55LW5700 Service Manual

Yes, sounds like it, you did get the power relay to come on so more likely that the PS-on signal from main is present but not the BL-ON signal, so you should verify that for sure.

[UND312DOG]

Re: LG 55LW5700 Service Manual

So I'm guessing the main board is rooted. It's funny that all the voltages as per tech manual are fine.

[UND312DOG]

Re: LG 55LW5700 Service Manual

Ok. Went ahead with it. Turned the tv on. Relay clicks, Backlights working.

[UND312DOG]

Re: LG 55LW5700 Service Manual

I'm not sure what resistors I have laying around. What's the minimum I need?

[budm]

Re: LG 55LW5700 Service Manual

In the link thoma provided, it shows you how to get the backlights to come on using resistors, you can look at the front or the back of the panel to see if it has glowing lights in the darkened room.
Right now we want to know if we have more than one board problem.

[UND312DOG]

Re: LG 55LW5700 Service Manual

I'm not sure where to test on the board for the backlights.

[UND312DOG]

Re: LG 55LW5700 Service Manual

As for back lights. Looking at the panel front on is completely black.

[UND312DOG]

Re: LG 55LW5700 Service Manual

So from p501 Pin 4 = 24.8v
L504 to ground (both sides) = 24.8v
Continuity either side of L504. And continuity from inlet side of L504 to L1801. Which is where it goes on the board.

[budm]

Re: LG 55LW5700 Service Manual

And backlights?

[UND312DOG]

Re: LG 55LW5700 Service Manual

Yeah mate. I'm getting 24v.

[budm]

Re: LG 55LW5700 Service Manual

BTW, did you check out that inductor in that link? And able to force on the backlights and power supply?
http://alpengeist-tvrepair.blogspot....-clicking.html

[UND312DOG]

Re: LG 55LW5700 Service Manual

Power

[UND312DOG]

Re: LG 55LW5700 Service Manual

Main

[budm]

Re: LG 55LW5700 Service Manual

Well we need to see the board and especially around the power supply connectors so we can give you the test points to find out what are missing.

[UND312DOG]

Re: LG 55LW5700 Service Manual

I turn the tv on via the switch. Hear the relay click. And nothing. A completely black screen. No light at all. The only light showing is a slowly flashing red standby light.

[budm]

Re: LG 55LW5700 Service Manual

So just to be sure, do you have backlights? and backlights are staying on after the flash?
Pictures of the boards to see what we are dealing with?

[UND312DOG]

Re: LG 55LW5700 Service Manual

Ok. So I have gone through the service manual and tested each output on the main board. Everything seems to be within spec. I'm getting power but no picture. So I guess it has something to do with the t-con board.

I know the tcon is getting power via lvds from Q507 12v. It's measuring 12v at Q507 and L511.

How do I test the tcon board. I can't find any schematics anywhere. The tcon board model is LG 6870C-0369C Ver 0.2 (2675E1).

Anything else I'm missing.

[UND312DOG]

Re: LG 55LW5700 Service Manual

Cheers mate. Cant help to try.

[thoma]

Re: LG 55LW5700 Service Manual

http://alpengeist-tvrepair.blogspot....-clicking.html

Perhaps?I know other lcd-tv!

[UND312DOG]

Re: LG 55LW5700 Service Manual

Anyone

Had a look at the main board. Model LD12C EAX64405501 (0). Ran through the diagnostic as per the service manual. All voltages were normal. Though I couldn't access Q507 as it was on the back of the board.

Before the screen blanked out. It went purple, flashed, came back to normal then blacked out.