Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

[fuxxy]

Working on this TV for a friend.
Model Number is Samsung UN55D6000
I have found the service manual, and attached to this post. Looks like multiple sets share this service manual.

After plugging in the TV, the red power LED flashes consistently, and the backlights flash occasionally.

My friend had a "service guy" of unknown qualifications look at the TV, and the "service guy" said the "brain" needed to be replaced.

There are only three boards inside this set.
* Power Supply
* Main Board - Sticker on board says P/N BN94-05038D. Other numbers on board: BN97-06022A, BN41-01587
* TCON

I'm still doing tests based on suggestions from other threads, will post back later with details.

[Andrew F. Ali]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

Your backlights, could be a failed LED or a few, or failed LED drivers, boost supply circuit.

[budm]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

We need good clear pictures of the whole back side of the TV showing all the boads, then we need to test Voltages at the connectors of the power supply board.
Power supply board is BN44-?????

[fuxxy]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

Thanks for the replies. I have attached pictures (front and back) of all three boards.

Power supply board is P/N - BN44-00424A

[fuxxy]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

On a whim, and diagnoses of other threads, I decided to open the LCD panel to look at the LED backlights.

I havent tested them individually yet, but there are obviously a few bad LEDS.

[dick_barton]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

Is that a crack through diode D9101 on the power supply?

Definitely some burnt up leds needing to be replaced

[fuxxy]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

Is that a crack through diode D9101 on the power supply?

Definitely some burnt up leds needing to be replaced

No sir, not a crack - simply a line of blue ink. Most of the diodes seem to have a blue mark on them.
Do we have a source for the replacement LEDS? Preferably the whole strip?

[dick_barton]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

You can try Shopjimmy

[fuxxy]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

I have the capability of replacing individual LEDS, if I knew which diodes I needed.

[fuxxy]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

I just tested all the LEDs on both strips individually.

All of the LEDs on the "Left" Strip are fine.
More than half of the LEDs on the "Right" Strip do not light.

I've marked the bad ones with a black sharpie.

Do you guys think the LED themselves are bad, or should I suspect the PSU overdriving the current for the LEDs on that side?

[dskall]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

Replace the strip Turn your backlights as low as possible. Update your firmware. Don't break your panel and you should be alright.

[fuxxy]

Re: Samsung UN55D6000FXZA - Power light flashing, backlight for a moment

I apologize profusely for the delay. I was browsing a new issue and noticed I never closed the thread.

After finally sourcing replacement LED strip for left and right, this set powered on and worked normally.

EXCEPT

After a month or so, it refused to turn off and stay off. It responded correctly to the power signal from both the remote as well as the capacitive touch panel on the set itself. It would power down, then immediately turn itself back on.

This was with only power connected, all other inputs disconnected, and wifi disabled.

That's a different issue completely, so I'm marking this one as solved.