Samsung UN60J6200 No power up

[bradcaps]

Greetings. I am taking a stab at my first TV repair. Its a 60" Samsung UN60J6200AF.

Initial findings: Plug unit in, not turning anything
on I find the 400v+ power supply to the LEDS is active.
I am not familiar with TV power supply but i find it odd this is seemingly in the 'on' state.
I do not get any reading across the 450v filter caps, but on the power diodes.

I find two regulators on the tv. At this point i get 12v from center pin on one and a slightly fluctuating 1 v. on the 2nd regulator, and its cold.

The two pinout cables from PS to the control board panel reads:
(10 pin dual layer) top row i read- ground, 12v, 12v, 12v, 12v. bottom row- ground, 0, 12v, .9v, .3v
The 4 wire cable to the panel are- 419v, 100v, 0, .8v

The TV is too heavy for me to see if there is a picture that isnt backlit.
I feel there is a bad regulator here but i would like feedback.

[neilc6]

Is the TV turning on or turning on with no backlight?

Testing for Samsung TVs

Unplug the cable between the power supply and main board and plug the TV in. The backlights should come on. If they don't, you likely have bad backlights though bad backlights can damage the power supply. If backlights come on and TV doesn't turn on with the main board connected, the main board is suspect.

2.Connect one ribbon cable at a time between the tcon and panel and see if one side displays a good image. If one side is bad, there is a panel fault on that side and all the boards (ps, main, tcon) are working.

[dskall]

No indicator light on front coming on? I suspect you aren't getting any backlights.

[bradcaps]

As far as I can tell I have no standby LED, no backlight, no nothing. Its dead. Can the regulator i pointed out as possibly bad be part of faulty standby power? Are schematics available?

[bradcaps]

"Unplug the cable between the power supply and main board and plug the TV in."

Still Nothing.

[bradcaps]

i am reviewing the troubleshooting lcd tv pdf from sticky. It says "The power supply has Standby 5vdc (5VSB, this is a MUST have before anything else will work,
when this voltage is not present, there will be no any indicator light on the front panel)"

This may confirm my suspicion. I am curious if the dead regulator i found is for the stand by power supply.

[dskall]

Need better pictures of boards, connectors and connector legends. Measure main cap across positive and neg. of cap.

[bradcaps]

Thank you i added more images with legends. The last image shows a large On/Standby voltage test point which i measured 12v at that point after simply plugging the unit in. This perhaps demonstrates that the standby circuit is faulty. The third photo shows the regulator outputting the 1v. Im going to measure if any voltage is going in to it.

[dskall]

What is part # on this regulator?

[bradcaps]

FDPF3N50NZ

https://www.mouser.com/ProductDetail...yrciRkHg%3D%3D

Its a MOSFET not a regulator.
Pin 1 = 0v, pin 2 around 400mV, pin 3 a few millivolt.

Fault is perhaps more upstream.

I get 388v across each of the large 450v filter caps.

[dskall]

What voltage do you get on the ps_on when you push the power button? That mosfet looks like it is for backlights. What voltage do you get on each grey wire picture 2 when you push power button?

[bradcaps]

ps_on i read 4.46v with or without power button pressed.
two greys read 412v & 92v with or without power button pressed.

[bradcaps]

According to this doc ps_on when off should be 0.2v, 3.3v when on. I am getting 4.3v A little concerning.

I am learning a microcontroller is used on these modern TVs to control analog ports such as like on an Arduino. This microcontroller controls the power LED. Either the microcontroller is faulty or its not getting power. We haven't found any anomalies with the power supply yet, 12v rail seems ok, therefore I suspect bad "main board" or microcontroller. I could diagnose it further if i had a schematic.

[dskall]

I would try heating up controller and then try and power on. Or press on controller and try powering on.

[bradcaps]

Good idea to check for cold joints. Will also try freeze spray.

[dskall]

Freeze spray won't help on BGA, which I assume you have with no mainboard pictures to go by.

[bradcaps]

No go with heat. The CPU is warm. The optical is lit. Poking with chopstick did nothing. I may have overlooked LED now i see it when moving power joystick. When power on I now see 5 blinks then nothing. I hold in power button LED flashes repeatingly.

[bradcaps]

Here is board

[dskall]

So going back to post 5. You have no backlights. Then need to find out if you have image on screen with flashlight.

[bradcaps]

After closer inspection I do see video.