Samsung QE75Q60A - bootloop, double blink, no display

[david sen]

Got this 75" TV for free, spent 10+ hours looking into solutions and troubleshooting methods before posting, I would hate for this device to become e-waste.

The issue:
backlight turns on, goes dim, turns off and the red light blinks twice.
unlike the numerous videos I have seen online I can hear an audible click from the relay switch on the p9wer supply board.

What I tried:
disconnecting the main board from the power supply = backlight turns on and stays on.
disconnecting the ribbon cable from the mainboard = backlight turns on, there is sound and the TV reacts to the remote.

The driver board is split into 3 parts, connected by two flat cables. Unfortunately, unplugging each end still causes the power cycle.
Since I cant isolate the issue I tried taping the main ribbon cable.
managed to isolate and tape 4 pins (15-18 from the left), still there is no image.
tried taping other parts of the ribbon cable, when I tape pins 1-4 from the right, the bootloop also stops but there is still no image.

Is there any way to proceed from here?

[Diah]

did you trick out the T-CON on mainboards to by pass the protection? there are 2 points on it need to jumper first..... if you dont then post clear photo on yours MB right side TOP

[david sen]

did you trick out the T-CON on mainboards to by pass the protection? there are 2 points on it need to jumper first..... if you dont then post clear photo on yours MB right side TOP

No I have not, this is my first time trying to fix a TV

taping just 1 most right pin on the ribbon cable stops the power cycle but there is no image.

[Diah]

what a funny boards no print sign on it,,,, you may have the print on the back side !!

however from your masking to stop the boot loop its 100% panel issue, search after and tested yours panel bufferr boards the middle parts we do have another threat i think same panel... there are D MOSFET and SPIas well C

[david sen]

what a funny boards no print sign on it,,,, you may have the print on the back side !!

however from your masking to stop the boot loop its 100% panel issue, search after and tested yours panel bufferr boards the middle parts we do have another threat i think same panel... there are D MOSFET and SPIas well C

Yeah, it's definitely a panel issue.
I still wonder If I can get any image to show up, even if it's bad.

[lotas]

Two blinks of the Standby LED indicate a problem in the panel, install a jumper and repeat the procedure with disconnecting the U-loops.

[david sen]

Two blinks of the Standby LED indicate a problem in the panel, install a jumper and repeat the procedure with disconnecting the U-loops.

No change in behavior, even with the jumper, disconnecting one or both U-loops still causes power cycle

[Takeatry]

I have a Samsung QN50Q with a similar main board experiencing the boot loop. I have narrow the problem to the right panel looking from the back. Tape method has worked to get a good enough picture in the past but never permanently. After letting the tv sit for any number of hours the loop would start again. Question for now is if I get a picture in do I need to remove the jumper wire on the main board or must it be removed

[lotas]

The jumper is placed for diagnostics.

[Davi.p]

If you were able to locate the right points on the Ma.Bo. you can probe the typical panel/tcon voltages, when jumper is on.. evidenty no voltages no image, but if yes voltages, then maybe a software trick is present, you know, today's Samsung are rubbish, you can expect everything, on the panel there is a memory chip, who knows..