Sony OLED XBR65A8G no video, PSU problem?

[Davi.p]

SVDD is Source voltage, the same as AVDD in many lcd tcon.. is around 15-17v
check again the 2 caps by disconnecting first the ribbon cables, some high capacity gives zero ohm at first touch of dmm

this discussion is nearly a trashcan, too much people possessing the same thread, also one with different issue.. i hate see this.. anyway my opinion is that most of the probabilities in all these oled discussions, is that there is a bad tcon, oleds are almost all from LG, LG has a.very.bad story of failing bga solder, i think this is a stereotype situation, the people gives the bad guy to a service shop, they say bad screen, they sells tcon as good, and all people are worry, i also suggested many times to get a tcon only if assured it comes from working tv / cracked panel.. i doubt people here undestand what i write.. bye..

[thetomma]

Hello

I've recently bought broken kd-65a8g with no image issue. Apart of that i bought used tcon ; -). Yesterday i saw this thread but did not start measuring boards yet. TV boots on older tcon, i can hear adnroid sounds, no image, no backlight. Green spots appeares on 0.5-1 second in left and/or right corners once i press power on remote. Oh the new TCON i got only 4 red diode blinks. Any suggestions?

[Davi.p]

This is a good interference useful for the thread, so this means one of two things, MB needs SW compatibility with TCON, i think is not so, or the two tcon are both damaged as they behaves differently, if you had read my last post you already has the answer on what to do (at least for me).. bye..

[thetomma]

This is a good interference useful for the thread, so this means one of two things, MB needs SW compatibility with TCON, i think is not so, or the two tcon are both damaged as they behaves differently, if you had read my last post you already has the answer on what to do (at least for me).. bye..

I think i got your point, i just saw your post and it was just the first idea, that i got broken tcon from the person who sold me as working, so both can be broken. Although it was mentioned in auction as tested. TCON's seems to be the same' i'll check all details once i got home ie serial numbers etc,

[cheebster]

From what i've tested tcon that isn't calibrated will still display a picture but not optimal on the lg oled panels, from my experience. So i've removed these caps and the line is still shorted. Guess that one is going to recycling.. Sad

[Davi.p]

you have to check to wich supply line those caps are connected to, i guess is SVDD, in that case the short is most probably in another hide cap, not on the cofs

[cheebster]

Ok. So might be an idea to cutout the panel's metal sheet at the bottom and reveal stuff under ? Or check with thermal camera/thermal injection on that line, see if i can see heat on the panel's metal sheet and cut more precisely where i see the heat ? Possible or not suggested ? This line is 12v/22v or so it seems ?

[thetomma]

with EVDD from power board to TCON disconnected - "new" TCON, it stops blinking 4 times and i hear the android sounds, once tv boot. Does it mean definitely panel is shorted and the whole TV can be put to thrash only? Apart of selling single parts

[thetomma]

Also im not sure that is important, when everything is connected, apart one of two ribbons from main-board to tcon board, then tv tried to boot with sound, kinda strange

[Diah]

Also im not sure that is important, when everything is connected, apart one of two ribbons from main-board to tcon board, then tv tried to boot with sound, kinda strange

only the lower LVDS which transport the SOS fault at module to MB
you can read the print at pins of error_xxxxxxx

[Davi.p]

1) have you checked or not to witch line the shorted caps belongs to?
2) with this evdd disconnected have you checked the basis supply lines if are present or shut down? Are you able to find and check them?
3) you cannot inject svdd line alone from what i remember, this is dangerous for the cof, you need first to supply the vcc line, that is 3,3v i think

[thetomma]

1) have you checked or not to witch line the shorted caps belongs to?
2) with this evdd disconnected have you checked the basis supply lines if are present or shut down? Are you able to find and check them?
3) you cannot inject svdd line alone from what i remember, this is dangerous for the cof, you need first to supply the vcc line, that is 3,3v i think

1. I checked i think all caps on tcon, none seems to be shorted, also fuses seems to be ok.
2. I havent checked power supply lines yet, you mean measure voltage on lines from power source board to tcon when tcon is connected to evdd and whe in disconnected?
3. Thanks for warning, by the way evdd is the same as svdd?

By the way on old tcon i found PCB in that area has a bit different color, it looks like it was high temperature there or some liquid:

[thetomma]

only the lower LVDS which transport the SOS fault at module to MB
you can read the print at pins of error_xxxxxxx

How to read it, by connecting jack->usb you mentioned in that post?

[Davi.p]

point 1 and 2, you have not understood, but, you tcon model is different from the one of Cheebster, i think one of you must leave the thread, too much confusion here!

[cheebster]

Oh well, got some progress here, cutted the metal plate so i could see the caps just a bit lower where the 4 lvds cables go from tcon to the panel, and found a shorted cap! Removed it, and tv doesnt blink anymore but no display, but ive got a butchered lvds cable from main to tcon. Gonna order a cable and see if it fixes this one!

[Davi.p]

don't forget the panel auto test method

[lotas]

don't forget the panel auto test method

This is not a simple T-CON (LG), and you can't just put it into standalone mode.

[Diah]

Oh well, got some progress here, cutted the metal plate so i could see the caps just a bit lower where the 4 lvds cables go from tcon to the panel, and found a shorted cap! Removed it, and tv doesnt blink anymore but no display, but ive got a butchered lvds cable from main to tcon. Gonna order a cable and see if it fixes this one!

put back yours original t-con if you didn't missed with it

after that you do hard reset by pressing the joystick down then plug in wall remove only after changing front LED from white to green

[cheebster]

This is not a simple T-CON (LG), and you can't just put it into standalone mode.

Here is the method posted by diah here;


If you got at first test EVDD Lower than 24V then drop down... and the VIN remain at 12V or also drops down ... then do the next

Second Test: ( running the power boards and the panel as stand alone )

1- disconnect the Main boards totally from Power boards and from the T-CON ( mean disconnect the socket coming from the power boards & disconnect the 2 LVDS between Main boards and T-CON .. unplug them from T-CON Side )

2- Disconnect the T-CON from Power boards ( unplug 2 sockets VIN & EVDD )

3. RUN POWER BOARDS as Stand alone ....
make bridge with R value 100 to 1K Ohm ( if the STBY 3.3V you can do it direct with out R but need to be sure 100% of the pins label )
A- STBY & Power_ON ( this will turn on REG12V ON )
B- STBY & TCON_12_ON ( this will turn on TCON_12V ON )
C- STBY & EVDD_ON ( this will turn on EVDD V On Max 24V )

if you confirmed all 3 Voltage in A,B,C you have ... then complete

4- RUN The panel Module as Stand alone
A- Feed the T-CON with VIN & EVDD V which you got at above points B & C


Are you saying this wont work with these models ? All i get is a black screen with either original or replacement t-con, even with that panel test mode.

I'm wondering if i should get a replacement set of cables. I attached 2 pictures, one is where i found a shorted cap, and second is the condition of the cable (can't even align it right it's so messed up, pins might not even be touching the socket pins properly.

Also wondering, is the missing CAP (the one that was shorted) an issue ? They were all connected together, figured out missing one wasn't a big deal, maybe guess wrong.

Rabbit hole!

[Davi.p]

I think that EVDD must be fed lately, the separate switching is there for a reason, first power on and tcon 12v together, then after a couple seconds EVDD.. every lcd screen has a power sequence, surely oled are the same way, i think perfoming like the.other says is an high risk or is surely a disaster..

.. check again caps on the panel, your new attempt, maybe new disaster..