LG OLED55A1PUA

[repair-it]

I appreciate your help & understand English is a secondary language for you so I just want to be sure I completely understand what you are saying.

I should only have 2 wires connected between MAIN board & POWER board. One of those goes from the 12VM out on the Power Board and connects to the appropriate connection on the Main Board, The other connects from the 3 and goes to one side of a 1K resistor and the other side of resistor goes to the 3.3v connection on the Main board. Disconnect both LVDS cables. Everything else remains connected. Then Power up. Is that correct? I now have the Service remote ... if that helps.

[Diah]

100/ correct... if you are lucky you will have some things on yours screen.. capture it and show me here

[RJARRRPCGP]

When I press power button, I hear a click, voltage goes to 20v then drops to 17v. The 12v does the same (goes to 12v) and drops to 7v after attempt to power up. I believe there is a faulty component issue on the power supply board but have yet to start testing. Pics attached.

Possibly early-covid-pandemic-related QC slump! It's in the period where there's possibly an above-normal panel failure rate. Early-covid-pandemic, is suspected of being the worst for bad panels! Same for other components, where I suspect being indirectly related to early-pandemic, due to factories of supply-chain being disrupted.

[repair-it]

Possibly early-covid-pandemic-related QC slump! It's in the period where there's possibly an above-normal panel failure rate. Early-covid-pandemic, is suspected of being the worst for bad panels! Same for other components, where I suspect being indirectly related to early-pandemic, due to factories of supply-chain being disrupted.

REALLY??! Oh geez, that was one thought I had.. a bad panel. Well, I do know these did come with a 5 year warrantee on the panel. Hopefully It'' turn on when I give it another shot tomorrow.Thanks for that info.

[Diah]

with yours service RC try to press P Only .. take look on the screen

[repair-it]

Will try Service remote. Should that be done after reconnecting all first? I tried (message #41) to no avail, nothing happened when I powered TV up.

[repair-it]

I plugged everything back in except lower LVDS cable and this is what I get when I powered up. Service remote has no effect on TV. Not sure if this is bad main board or T-CON. Power LED will not illuminate. Optical port not illuminated.

[Diah]

I plugged everything back in except lower LVDS cable and this is what I get when I powered up. Service remote has no effect on TV. Not sure if this is bad main board or T-CON. Power LED will not illuminate. Optical port not illuminated.

keep it in this test condition...
1- measure the sockets 1 & 2 i mentioned early on the PSU and tell each V
2- as it is on... if you use yours Original RC can you put it in stand by state ? if yes... you need to check yours service remote with yours Mobile Camera ( Not I Phone one ) to see if you press any key you could see the IR LED blinking. after you clear this point and Service RC working 100& as the TV in STB... press on S.RC Power only and check if it is on and Optic port etc.... usb 5V there or not.and the 2 sockets we talked on.

[MASTER_TECH_101]

Such a waste of time. Unplug two LVDS cables TV turns on, Bad panel. End of story and troubleshooting.It does not matter is it Tcon or panel itself, you still have to replace whole thing. OLED LG sucks.

[repair-it]

Had to step away for a few days to do some other repairs. Ordered replacement Main Board, it arrived & was installed. Powered TV up, got the start up tone(didn't get that in the past) and have optical light. Pulled both LVDS and have vertical lines on panel as shown in last pictured I had attached (message #47) All expected voltages were present. POWER ONLY button on Service remote does turn TV on, LED blinks 3 times then LED turns off, set remains on but Power ONLY button no longer operates TV, had to use POWER button to turn off (with lower LVDS cable disconnected). When ON all I can see image on panel is same as attached pic. Does this indicate a bad panel or is it a T-CON board issue?

[Davi.p]

i think you.must provide first the 12v, then the 24v, there's a power sequence to respect, otherwise the panel maybe could fry..

[lotas]

LG's panels are also dying, like Samsung's, especially OLED.

[Diah]

never saw oled screen show this white lines .... this why i would never say OLED Module Failure unless it tested in standalone..... questions.. is this your home TV or you get it some where ells ?

[repair-it]

never saw oled screen show this white lines .... this why i would never say OLED Module Failure unless it tested in standalone..... questions.. is this your home TV or you get it some where ells ?

For a customer. Actually the lines are multi color.

After this first time experience - I am a bit concerned about trying to repair these newer OLED type TVs. The more research I do into this newer technology, I am seeing a pattern of eMMc chip failures after about 2 years. I just got another 2 year old TV (SONY Bravia 75" OLED) in yesterday with the same issue - will not turn on and after some quick research online, it seems a common fault is eMMc failure. There is an eMMc chip on the T-CON board of the LG OLED TV that I've been trying to repair and now I suspect it could be an issue. I'm not sure if the MAIN board uses this chip as well, I never removed the heat sink to take a peek, but replacing the MAIN board with a new one did allow for the board to start because I got the start up tone that I did not hear before the board was replaced.

Unfortunately, finding a replacement T-CON board for the LG has been difficult. I will probably be staying away from trying to do repairs on these type of TVs in the future unless reliable replacement parts become more readily available. There are too many variables with these OLED sets and seems too many opinions on how to fix. Some say the T-CON is matched to the panel and cannot be replaced, others have said the same for the MAIN board being matched to the set or the boards are matched to each other. I'm still suspect that this new eMMc technology is the issue. Unlike a BIOS chip, these are difficult to reprogram, remove & replace and find pre-programmed chips that are reliable.

[repair-it]

i think you.must provide first the 12v, then the 24v, there's a power sequence to respect, otherwise the panel maybe could fry..

Yes, I did not exceed 12v while using 1K resistor when trying to get main board to turn on. I removed the T-CON board and applied 6v 1A to it, there was no unusual amp increase displayed on power supply. I then looked at the board with IR cam and did not see any hot spots. I also did a continuity check of all caps and all were ok. My *guess* is it is a faulty eMMc chip or panel went bad.

[Davi.p]

you did not followed me well, i told that for testing the screen, probably needs to feed.first the 12v so the tcon dc dc and logical initializes, then the 24v, i don't know what it is used for it, never searched informations on oled, anyway i'm with you thinking that emmc on tcon could be a culprit, together with ram, cpu, i'm trying to make some experiments these days, i need a certain item, honestly i'm often in the doubt if let my theories and discovers public or keep them for myself, money are always few, but environmet is the most important.. maybe i'll share it with someone.. maybe the solution is much easyer than how it seems..
My strong suspect is that here there is programmed obsolescence..

PS: only Sony needs MB<>tcon pairing..

[Diah]

For a customer. Actually the lines are multi color.

After this first time experience - I am a bit concerned about trying to repair these newer OLED type TVs. The more research I do into this newer technology, I am seeing a pattern of eMMc chip failures after about 2 years. I just got another 2 year old TV (SONY Bravia 75" OLED) in yesterday with the same issue - will not turn on and after some quick research online, it seems a common fault is eMMc failure. There is an eMMc chip on the T-CON board of the LG OLED TV that I've been trying to repair and now I suspect it could be an issue. I'm not sure if the MAIN board uses this chip as well, I never removed the heat sink to take a peek, but replacing the MAIN board with a new one did allow for the board to start because I got the start up tone that I did not hear before the board was replaced.

Unfortunately, finding a replacement T-CON board for the LG has been difficult. I will probably be staying away from trying to do repairs on these type of TVs in the future unless reliable replacement parts become more readily available. There are too many variables with these OLED sets and seems too many opinions on how to fix. Some say the T-CON is matched to the panel and cannot be replaced, others have said the same for the MAIN board being matched to the set or the boards are matched to each other. I'm still suspect that this new eMMc technology is the issue. Unlike a BIOS chip, these are difficult to reprogram, remove & replace and find pre-programmed chips that are reliable.

i don't know from where you got this wrong INFO about OLED T-CON ? there are NO eMMC on T-CON at all... and the it Function not much different from LCD TV. the one things different on OLED it got to VCC T.CON 12VCC & > 21 OLED VCC which it power the cells. no more or less,,, it had RAM and SPI / NOR and CPU. any way... if you are repairing TV... you should have under hand some other type of power boards... for example i have one from Vestel.. i jumped it as standalone so i can use it always fas external supply for 3.3V, 5V , 12V and 24V. so i can test any TV / screen.. MB... T-CON with it... thought this boards i will never put it as replace at any coast.. so you need to look round you may have one with this specification range.

[lotas]

there are NO eMMC on T-CON at all....

What is this then?

[Diah]

What is this then?

this related to ThinQ AI.. funktion

instead of NOR / Sspi they used this.. if you get it out from the circuit you will see howmany pins are used 12-16 only... how it come eMMC work with just view PINS

[Diah]

just let the T-CON driver boards and the OLED module connected nothings ells with them, fed them with 12- 24V and you will see the screen if it fault