Dead LG OLED55BX

[korn88]

Hi all! I'm learning so please be patient with me.

My LG OLED55BX decided to not turn on anymore after a bit more than 3 years. I've read the forum quite a bit and have done some basic troubleshooting, but I'm stuck and need help with the next steps.

Symptoms:
I turn on the TV and hear 1 relay click. Stand-by light blinks, light can be seen in optical connector, no image on screen and 3-5 seconds later another relay click sounds and TV turns off.

What I've tried so far is:

• Disconnected lower LVDS cable -> Optical connector light stays red, no second relay click
• Measured voltages with lower LVDS cable disconnected: To mainboard 12 and 20v look good. To T-CON 12v looks good, 22v stays until 18 seconds later when it drops to 20v. Is this normal?
• Shorted pin 40 on lower LVDS cable -> TV turns on normally and can be operated as usual, but vertical ghost lines can be seen in the middle of the screen (similar to vertical banding). This was not there before, which makes me think it's either T-CON or panel issue. The rest looks healthy, no dead pixels or anything.
• Tried cleaning the panel/T-CON connectors with no changes.
• Bought a very cheap T-CON from a broken TV to try. Same symptoms, including the same vertical lines.

All points me to a bad panel, but I want to know what you think. What confuses me is the drop to 20v in the 22v line. Is this normal? Or could this be a bad power supply? Could it be a symptom of a shorted panel?

I don't have a service remote, will I find any useful information about why the T-CON is sending the shut down signal to the main board?

These are the white vertical lines:


Any help is welcome! Thanks!!

[Diah]

nothings you can do .. bad panel.. and its the reason of dropping the EVDD Voltage.

just be careful... grounding the SOS pin on lower LVDS could cause real fire at the panel.

[Diah]

nothings you can do .. bad panel.. and its the reason of dropping the EVDD Voltage.

just be careful... grounding the SOS pin on lower LVDS could cause real fire at the panel.

[Davi.p]

have you asked the story of donor tv of the tcon? to be safe it might be from a perfectly working set but cracked panel, i don't know LG panel management software working, i'm not engineer, but pops also a doubt that software panel calibration can happen not automatically at first power up or few minutes after.. try to let the tv working non stop for at least 24h, then judge it..

[korn88]

nothings you can do .. bad panel.. and its the reason of dropping the EVDD Voltage.

just be careful... grounding the SOS pin on lower LVDS could cause real fire at the panel.

Thanks, that's what I thought. I blocked the pin during only a couple of minutes to see what was going on and reset the main board to factory settings (to remove personal information). I promise I won't use it with the pin blocked 😂

[korn88]

have you asked the story of donor tv of the tcon? to be safe it might be from a perfectly working set but cracked panel, i don't know LG panel management software working, i'm not engineer, but pops also a doubt that software panel calibration can happen not automatically at first power up or few minutes after.. try to let the tv working non stop for at least 24h, then judge it..

I haven't asked but it was probably from a cracked panel, seller was selling only some spare pieces. But in any case, the new T-CON didn't solve the issue. So it must be the panel, it would be really weird if both T-CONs have the same exact issue displaying vertical lines in the middle. Also everything that I've read points to bad panel when having vertical lines like these.

These lines appear only when blocking the SOS pin in the lower LVDS, so calibration won't help much. There must be a short in the panel like Diah said.

[Diah]

Thanks, that's what I thought. I blocked the pin during only a couple of minutes to see what was going on and reset the main board to factory settings (to remove personal information). I promise I won't use it with the pin blocked 😂

IN_STOP command will do primary deleting all personal information).

[korn88]

IN_STOP command will do primary deleting all personal information).

Does it work even if T-CON is sending the SOS signal?

That's great to know for the future. Thanks!

[Diah]

Does it work even if T-CON is sending the SOS signal?

That's great to know for the future. Thanks!

IN_Stop will take effect at any method you have optic output are always lit on red... by disconnect the lower LVDS or disconnect the EVDD sticker from T-con driver boards... of course it will be done in blind way as no screen... IN_Stop send then follow with 4 digital No. code

[Davi.p]

what i want to know is if you ever tried tv with new tcon and without pin tricks, if tv started well with image this would.be a sign of bad original tcon..

plus, have you watched the lines.with.magnifyer? are those white lines or what? i wonder if OLED construction has.the.same typical and almost stupid.flaw of some LCD where signal FPC are not been entirely covered with insulation enamel so it builds oxydation during time... this is a bad story for a thousands euro set.. you can in that cas try to heat with hot air that panel section hoping to see an.improvement (but it is not the right method to get rid of it, only a test)...

[korn88]

Sorry if my original message was not clear about this part.

I tried the new T-CON without the pin blocked and it doesn't work. It has the exact same issue than the original T-CON: relay click when turned on and another relay click 3 seconds later.

I haven't watched the lines with a magnifying glass. I wouldn't have the knowledge to tell what's going on. If I zoom in the closeup photos I took, I can see the lines are actually of the right color, but brighter. That's why I originally thought the issue could be the T-CON and wanted to give it a try, because it seemed like some aggressive vertical banding.

[Davi.p]

But i'm wondering why tv does not showed any sign of video at first power on of new tcon, if it is so, i think that screen must be turned on completely with some image to be possible that tcon detects error.. or.. this protection flag is memorized on a memory in the panel small boards.. can you try a deep reset through smartphone, ir blaster and wav files? this means sending in-stop code file.. Okay this can be of no help if after reset new tcon detects newly bad signs from panel, but one can try.. maybe old tcon drived bad the panel and feedback from it is bad, usually all the timings also of clocks are decided by main chip, if a clock line does not work, the vgl or vgh (von,voff) can be overloaded..

[Diah]

But i'm wondering why tv does not showed any sign of video at first power on of new tcon, if it is so, i think that screen must be turned on completely with some image to be possible that tcon detects error.. or.. this protection flag is memorized on a memory in the panel small boards.. can you try a deep reset through smartphone, ir blaster and wav files? this means sending in-stop code file.. Okay this can be of no help if after reset new tcon detects newly bad signs from panel, but one can try.. maybe old tcon drived bad the panel and feedback from it is bad, usually all the timings also of clocks are decided by main chip, if a clock line does not work, the vgl or vgh (von,voff) can be overloaded..

what clock you are talking about and like drunk suggestion... please stop this act with some things you don't know how it works.

[Davi.p]

.

[Davi.p]

can you check if with new tcon there is the same change from 22v evdd to 20v?