Samsung UN50KU6300 Leds wont stay on

[handsworth]

I'm doing some basic diagnostics on this tv trying to find out if the main board, PS or leds are causing the problems. There is no T Con. When tv is turned on the Leds come on then go off. 20 sec later, they repeat the process over and over. Ok so I pulled the connector from the main board and replugged. All leds are lit and stay on although some had turned blue. I switched PS and got the same result. Switch MB and the results are same again. Also disco'd lvds from panel, same results, I just ordered a new set of leds cuz I would need them anyway. What is going on here? Any advice.

[neilc6]

Re: Samsung UN50KU6300 Leds wont stay on

I have seen bad LEDs flash on Samsungs. Without protection shutdown, one intermittent LED can cause the whole string to flash.

[handsworth]

Re: Samsung UN50KU6300 Leds wont stay on

So I just installed all new leds and the same is happening. Switched power supplies and same results. PS alone keeps them lit. Im thinking MB at this point. Any suggestions?

[lotas]

Re: Samsung UN50KU6300 Leds wont stay on

The problem may be in the panel itself.

[Storyteller12]

Re: Samsung UN50KU6300 Leds wont stay on

Some of these Samsung models have bad caps on the panel driver board. Check and see if any are shorted. If not try the tape method to see if it keeps the backlights on. If so it’s the panel itself as mentioned.

[CapLeaker]

Re: Samsung UN50KU6300 Leds wont stay on

Everything disconnected, besides the backlights connected to the power supply, the LEDs should turn on and stay on as long the PSU is plugged in and getting power.

[Davi.p]

Re: Samsung UN50KU6300 Leds wont stay on

List or make a photo of the PSB table of the connector to main board signals. Have you installed new leds or led bars? Try to power on with panel or half panel disconnected. Try to locate a fuse on mainboard.

[MahdiA]

Re: Samsung UN50KU6300 Leds wont stay on

To Diagnosis ;
Unplug main from smps, If backlight remain
Unplug address from main, If backlight remain
Test the address one by one.
To identify the problem.

[Davi.p]

Re: Samsung UN50KU6300 Leds wont stay on

Unplug main from smps, If backlight remain

already said

address

what the hell is?

[handsworth]

Re: SOLVED: Samsung UN50KU6300 Leds wont stay on

So I stopped replacing parts for this seemingly easy fix and started investigating posts #3 and 4. This is what I found. Its not an led problem but a screen issue. Seems the tv was power cycling.

1. Power cycling, backlight turning on and off or no picture on this model is because of a bad screen, replacing main board does not solve these issues. By the way, if you have other issues just keep in mind to update the firmware on this main board right after you installed it by connecting it directly to internet otherwise main board will go out again in a short period of time (Firmware must be updated on all Samsung KU series after replacing the main board with a new one)

2. In another post I found on this site, if everything is connected except the panel tabs, it still will not turn on, but the leds will blink. This is a KU tv issue.

Hope this helps someone