LG OLED 55C8 SWITCHES OFF WHEN POWER DEMAND

Kaiser73

Novice Member
Dear friends,

I am the owner of an inop LG OLED 55C8. After 2 years and 5 months the TV is INOP. The problem is the following:

I switch on the TV and after several minutes, when it heats up, the tv switches off but not always at the same time. What I have noticed is for example that
when I start Netflix and there is power consumtion ( because HDR mode is on) it stops always beween 19 - 25 seconds after I initiated Netflix.

There are no devices conected to the tv. The LG technical service told me it is the OLED display faulty....about 1000€ .... but I thing that the problem is related to the power supply.... How could I know it? I have no spare parts... Do you thing Is the power supply too?

Thank you very much for your help,
I would appreciate any suggestions and your knowledge!!

Best Regards,
Kaiser73
 

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encaser

Member
C8 has a known problem with some of its power boards that can overheat and switch off and on. LG offer a free swap out and you can find details on their website.
 

Kaiser73

Novice Member
Hi Encaser, thank you very much indeed for your help and replay. I have tried to heat the power supply and the processor with a heat gun, but no way to know if it is the power suppply, the main board or the oled display.
I have gone to the website og LG and my model number does not apply to the ones that had the problem...

I have seen also that there is an horizontal line along the display, I ave disconnected and connected again all the databuses and I have cleanded them, but no results.
After 1 minute aprox, not allways at the same minute/second, it switches off. Then I can switch it on again and works, but again after 1 minute or 20 seconds (if there is demand of power) it switches off again.

I have recorded a video with the problem.

Could anyone help me please to know how can i discard if it is a problem of the power supply, the microprocessor or the oled display?

Thank you very much for your cooperation and help!

Kaiser73
 

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JayCee

Distinguished Member
Did LG diagnose the cause of the problem by examining your TV or have they said it is a known cause for that particular model?
 

Epistemon

Active Member
Sounds like you have two coincident but separate problems: The panel line and the power supply shut off. I doubt the latter causes the former.

Regarding the latter, you can get a replacement power board for around 50EUR, part number
LG PN: EAY64749001 (PCB: EAX67858001)

I have one on sale on eBay for 20GBP but shipping to Spain is probably not value for money for you. There are plenty of suppliers in Spain anyway.

I infer that you've done the difficult bit by removing the back of the TV. Changing the power board is easy in comparison. Watch out, some of the capacitors have high voltage for a long time after disconnection.

At least then you will have a stable TV to investigate the panel issue.
 

Kaiser73

Novice Member
Thank you very much for your help, I really appreciate it.
What I have observed is that when I switch on a serie in Netflix that is recorded in high quality video, the tv switches off. With films that are recorded in hd, I can stay a long time watching tv, but not with high quality videos.
I have replaced the power board capacitors, and I have inspected the board with a magnifier in order to know if it is a hot/cold welding, but no results.
I really think the same as Epistemon, that may be there is a fault in the power supply, but my question is, how do I now that it is not the panel that is telling the microprocessor there is a fault in the dsiplay and then the microprocesor tells the power supply to switch off? Entering in Save mode...
I do not know if I have explained it well. ...

About the horizontal line.... i really don´t care ...i thing it is something related to the source driver IC... you know...I can live with it..., as Epistemon says....I prefer to have a stable tv... :)

Thank you very much for your interest!!

Kaiser73
 

Kaiser73

Novice Member
Did LG diagnose the cause of the problem by examining your TV or have they said it is a known cause for that particular model?
Hi JayCee,

Yes, LG diagnose the problem and only says it is related to the panel...but they do not say anything related to the power supply...and the panel works...with an horizontal line...but works... not to through to the basket a tv of 1400€ because there is an horizontal line ...
It hurts!! Only with 2 years and four months...

Thank you very much for your interest and support.
 

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