LG OLED55CX Clicking No Power

[cheebster]

Hello, i have this OLED here, as the topic says OLED65CX.

TV shows standby led, when pressed the PSU clicks, then shut down.

Disconnecting the 12V VIN from the T-Con, make the TV boot up, led flashes like normal and it stays on.

What i've tried so far:

I have a working TV, an OLED55C1. Similar TV... Took all the boards to the C1, 1 by one, and everything works. So basically, all of these boards from the defective CX (PSU, Main, TCON) works either 1 by 1, or together on the working C1.

However, none of the C1 boards work on the CX, same issue remains. Only thing that changes, the C1 mainboard doesn't even try to boot on the CX panel, it stays red solid.

I have the OLED PANEL TESTER 2022 little jig by LG as shown here : https://www.youtube.com/watch?v=6kNcFzLZzmM and when tried, i get the CX panel to show all colors, no problem there.

So basically:

PSU tested OK on another TV
Main tested OK on another TV
T-Con tested OK on another TV
Panel tested OK by LG testing Jig.

My logic fails here. It still points at the panel itself though, but IDK what to try next. It seems the LG diag jig isn't that reliable after all ?

I also tested cleaning the FPC flexes connections to the panel from the T-Con, the cables. No luck..

The CPU on the CX shows no signs of having any kind of overheating damage either (well, it works on the C1 too)

If anyone has an idea on this one ! Thanks..

[Diah]

you have one or more OLED Cells pulling more currents which trick the T-CON error detect and send it to MB MICOM PIN 6 as i remember to shutdown the TV.

Korean they play with JIG .. but they didn't offer SW to remove this error detect so user can remain use his TV when it show no lines or big damage on screen... for example Philips do give file for this removal on OLED sets.

so if you have clean screen displaying the pattern then yours only way to manually disable this rail between T-CON and MB. at t-CON side

[Diah]

one things more.. you got until now good experiences with OLED so you know how to start with Panel buffer boards

[cheebster]

Hello, thanks for your replies Diah. Buffer boards, well they are hidden under metal it's kinda hard.

Ok so, to bypass the error detection, you say micom pin6.. I found this on the T-CON, pulled the pin on the connector backside, still does not power on.

Do we have an idea on how to bypass the error detection ? I have tried this rail also on a defective sony oled, but it doesn't power on. Cutting the track doesn't do the job it seems

Do i need to ground this pin ? Is there any reliable pinout/schematics of these connectors/tcons available ?

[cheebster]

Oh, i got the tv running! Running out of time this morning but messing with a small piece of tape, i think pin 41 blocked will confirm. What i can tell now, is that tv powers on and image is great.

Will also check service menu to find out what's happening, what faults were recorded in the main.

[Diah]

Oh, i got the tv running! Running out of time this morning but messing with a small piece of tape, i think pin 41 blocked will confirm. What i can tell now, is that tv powers on and image is great.

Will also check service menu to find out what's happening, what faults were recorded in the main.

it would be nice of you to explain with photo to other new user so they know what we are talking on.
i wrote before now you are expert with OLED .... enjoy

[cheebster]

Hi there, yes sure. TV works fine, and by inspecting the frame i see a missing bit of paint near the right corner, bottom. When i press the panel the picture gets distorted (prolly a short between frame and cof or similar. By using a piece of paper slided between panel and metal frame pressure does not create fault anymore.

So here is a picture of the service menu showing the BDP errors telling the tv power on problem was a panel fault. However, now it's restored to full usage. Not an expert by any means imho !

Thanks,

[Diah]

you have burn image on screen i can tell from photo... if this the case you need to send IN_STOP , or downgrade then update complete firmware.

[Diah]

did youown now the JIG tool ? i would like to DIY it to be easy tool to users test OLED Panel and its T-CON, the top side we do know and we did it in different way to switch PW_ON & TCON_ON & DRV_on... but the interesting to have the downside of tool if there eeprom to switch pattern or just in_circuit dummy and the rest T-CON do it within eMMC
any one have an idea and this tool please update the downside... at least we will have cheap tool for all

[nomoresonys]

Ok, so to be clear, you had a panel problem, using the piece of paper made it work correctly. Does this mean you no longer need the piece of tape that you used to block the signal?

[bohaboha]

Ok, so to be clear, you had a panel problem, using the piece of paper made it work correctly. Does this mean you no longer need the piece of tape that you used to block the signal?

nomoresonys i think it was that because he did not talk about the tape anymore and i did use that solution long time ago

[cheebster]

Yep, using this tool Diah and the backside doesn't have any form of chip or anything just the pcb, very simple tool indeed. Yes nomoresonys i used tape on pins 39-41 to block the signal. I also found the panel fault, on right side coner an object hit it, so it creates a short under the panel. I slided a soft plastic piece between metal frame and panel corner, prevented the short (i could make it freak out by pressing the corner) and now even with pressure i isolated the fault. Tv works like new !

[nomoresonys]

Thanks Bohaboha and Cheebster.

[bohaboha]

Thanks Bohaboha and Cheebster.

good to know a piece of tape and the tv works again