2 LG 55EA970v OLED no more screen / no audio
Hi
I've found lot of help here with already answered questions, but it seems I'm in a different case.
My LG 55EA970V OLED screen from 2013 was working well and stopped suddenly while in use, with black screen / no more audio.
I've already checked the following :
- power supply out voltage is fine at 3.5v 12v and 24v pins on the main P202 connector (picture below)
- when powered on by remote I can hear the relay "click", the LG logo lights on, then the PWR_ON pin switch to 3.5v at P202 connector (picture below), but no screen display (and no sound)
- the DRV_ON pin remains at 0, so there is no 20 volts at the bottom connector (P201)
I thought the main board was faulty, so I ordered a (used) one from a China supplier, but the result are the same (first PWR_ON, then no DRV_ON).
I had chance to also get another power supply board, so I've changed it too ... with the very same results.
I've followed part of the SMPS test document, but I can understand what component can be faulty. Is it possible that as the TCON remains unpowered, the main board considered it as faulty and turned into a "fail" state, refusing to start ?
While I can change the TCON too, I can't understand why the DRV_ON remains off.
I've also tried to plug a USB key with a small led indicator, thinking it may light up if the main board boots. But whichever port I use, the key remains off. So I guess the main board (old one or replaced one) does not boot.
I've noticed 2 little switchs on main board. The first seems to power off the device, but I can't find any doc regarding the purpose of these.
Will much appreciate any help from electronic warriors here !
Regards
Update may 7th
Es esta una buena pregunta?
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2.3mil 
Some news.
I had a chance to grab a tcon and swap it, but very same results.
In the meantime I forced DRV_ON UP, so 24v is delivered. It doesnt change the results, MB seems unresponsive.
I ve also connected PS 12v to the LVDS fuse on tcon, with LVDS unplugged, and power cycle test is fine : red, green, blue, white, black no default on panel. I've tested with the 2 tcon I have, both seem fine.
So I m stuck with this issue. DRV_ON remains 0v. And I have no 12v on LVDS output from MB.
@oldturkey03 Any advice ?
- de Pedrolane
@pedrolane you've got a lot going on there :-). Anyhow, why and where did you do that? No 12V on T-con whatsoever? Let's see your power board. You did they you have a new main board, correct? what do you mean by this "no default on panel"
- de oldturkey03
Why and where ? At home, and because I would like to save this TV set :-)
No, I dont have 12v on TCON, even with DRV_ON forced UP.
It seems hte MB never routes 12v through LVDS.
I ve checked all the voltages on PWR board, these are fine in standby mode, as well as with PWR_ON UP. I have 3.5v 12v 20v.
And I have 24v at the bottom when DRV_ON forced.
I did receive an other mainboard, but it doesnt "new" at all (rust on connector, missing header etc). I tried it anyway but results are the same.
By "no default on panel" I mean that the color cycle seems fine : bright color, no missing lines, no dead pixel etc.
- de Pedrolane
@oldturkey03
When PWRON I can measure some 12v on various coil / capacitors on MB. But no 12v on first pins of LVDS, neither MB side nor TCON side
Can't understand ...
- de Pedrolane
@pedrolane "At home, and because I would like to save this TV set" Awesome :-)) We do want you to help with that. Does your power board connector specify the 12V for the T-Con board. Yes, your panel is ok, I was just confused by the term "default"
Any chance you can post some pictures of all the boards?
- de oldturkey03
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