SONY Bravia OLED XR-77A80J will not power on

[repair-it]

SONY XR-77A80J shuts off as soon as it is powered on. It goes into standby ok when plugged in but when power button is pressed, relay clicks and tv powers off. Power supply board makes a sound that sounds like momentary coil whine when it clicks off. The main board appears to turn on and has working optical.

I pulled the power supply board for visual inspection & there wasn't anything obvious. I am not sure how to go about testing this OLED as it is a bit different than the last one (LG) I tried to repair. The only voltage listed on the PSU is 12v for T-CON. The 12v is not present at either connector. There are 4 opto's on the PSU so I am wondering if maybe there is an issue with secondary side possibly not getting power.

This TV is REALLY big! 😳

[Diah]

disconnect the 2 socket in Red color and power on... check if it remain ON and Optic lit on... if yes... put them back and disconnect the only LVDS in yellow color... power on and check if it go On and the optic lit too.

IF no result . you need to take out the PSU alone on the table and do the following testing Only on Socket 6401
1- plug it in wall and test Pin 6 STBY. there should be 3.3-5V. if this the case then
2- jumper it to PiN 5 Power_ON the Relay will click once
3- keep the Jumper in pint 2 and jumper PIN 6 to Pin 1 TCON12V_ON you will have on socket 601 12V
4-Always keep the Jumper in point 2 in place and make another jumper from Pin 6 to Pin 3 EVDD_On you will have on socket 501 19-24 V for EVDD

if all V fine then yours PSU fine.

[Diah]

if yours work on the post above after point 4 all fine.. put back yours PSU in place and keep the jumpers all in place... don't connect the socket 6401 which it goes to main boards...
disconnect the 2 LVDS ( in yellow from T-CON side ) the other 3 sockets on t-con should be connected ... power on the set yours screen should come ON and you can see if there issue on it... this is Standalone test for T-CON and panel..
if there are color pattern and the screen clean.... mean yours TV issue at MB.

[repair-it]

ok, I think I have a faulty PSU. I did as you said and I do not have any standby voltage so I didn't go any further. Also, there is no voltage present on the 2 large caps on the secondary side. Before I disconnected everything I powered up the board and main caps went to 380v but then board shut down. After removal and powering up, main caps only went to 160v. What really sucks is both Main Board & PSU for this TV are hard to come by right now.

[Davi.p]

As per situation in post1 you must have STB, at standby state at least.. the test suggested is wrong if made to test PSB, since white connector on tcon feeds 12v, by detaching only 2 connectors if the tcon is SC then PSB shuts off..

post a 2000x2000 pic very bright no flash of tcon, need to check power components..

[EazyBone]

I don't think you tested enough. I'm pretty sure on stby the main caps will be lower at 160 and when PSON triggers they'd go up to 380. I don't think you've done enough testing.

Those 2 caps on. Secondary side will only show voltage once tcon 12v happens. So they are going to appear dead.

I had this same TV a few months ago, tested a million times. With everything disconnected check the stby pin again for voltage. What is it?

But this kit is at shop jimmy for $300 for all the parts, and you can also make offer on there as well, which worked for me.

[repair-it]

I don't think you tested enough. I'm pretty sure on stby the main caps will be lower at 160 and when PSON triggers they'd go up to 380. I don't think you've done enough testing.

Those 2 caps on. Secondary side will only show voltage once tcon 12v happens. So they are going to appear dead.

I had this same TV a few months ago, tested a million times. With everything disconnected check the stby pin again for voltage. What is it?

But this kit is at shop jimmy for $300 for all the parts, and you can also make offer on there as well, which worked for me.

Yes, what you say about the voltage difference makes sense. The problem is finding replacement boards. The other issue is reprogramming the set after board replacement unless you can find a matching set. Far more than I'm getting paid to do, so it is going onto someone else to mess with. Not worth my time & effort.

[EazyBone]

Alright.. there isn't different versions for this set they I know of. All good. Good tv to go to waste