Samsung UN65ES6550F No picture, no backlight

[Slimpickins]

Problem Statement:
As the title says 65” Samsung LED TV no picture and no backlights verified with back removed from TV.

When T-con board is unplugged backlights come on for about 1 minute then the lowers turn off, in another 15-20 seconds the remainder turn off.
With main board disconnected all backlights come on and stay on.

I have voltage measurements in attachments for CNM801 PB to main and CNL802A/B LED output

I am thinking this BN44-00545A power board has an issue but would like to confirm with your help.

Any thoughts or troubleshooting assistance would be appreciated,
Kevin D.

[dick_barton]

Re: Samsung UN65ES6550F No picture, no backlight

Can someone enlighten me as to what OD_Level & OD_ON are?
Thanks


If you press Menu on you remote and shine a torch on the screen, can you see it?

Are there any board legends for the connections on CN802A & CN802B

[Slimpickins]

Re: Samsung UN65ES6550F No picture, no backlight

I couldn't see anything with the flashlight test

The only legend for CNL802A/B is in the pic labeled power bd output
210vdc, 4ch, 216ma

[dick_barton]

Re: Samsung UN65ES6550F No picture, no backlight

It looks like (guess work) that each connector is driving 4 led string so 8 in total at 210V, 216mA per string. If you disconnect the connectors, what voltages do you get at 802A & 802B?

Edit
I've just taken a look at your photo again and you give the open circuit voltages at the connector

[dick_barton]

Re: Samsung UN65ES6550F No picture, no backlight

With main board disconnected all backlights come on and stay on.


So what are the voltages on those connectors with the main board removed and backlights on.

[budm]

Re: Samsung UN65ES6550F No picture, no backlight

Since the backlights come on and stay on without main board connected, it is telling us that the power supply and the LED drivers are working, the power supply board has pull-resistors for self test when main board is not connected.
So what do you get if you leave toon disconnected but everything else connected, can you turn on the TV and get the backlights?
It looks to some thing is killing the Pam dim signal.

[Slimpickins]

Re: Samsung UN65ES6550F No picture, no backlight

Since the backlights come on and stay on without main board connected, it is telling us that the power supply and the LED drivers are working, the power supply board has pull-resistors for self test when main board is not connected.
So what do you get if you leave toon disconnected but everything else connected, can you turn on the TV and get the backlights?
It looks to some thing is killing the Pam dim signal.

For confirmation are u asking what I get with T-Con disconnected? If yes, with T-con disconnected i get back lights all on for a little more than 1 minute then half go dim then off and in another 20 seconds the remainder backlight go out.

If you are referring to "toon" I am not familiar with that?

Is there any means of determining if the "Pam dim signal" is being affected?

Really appreciate your help.

[Slimpickins]

Re: Samsung UN65ES6550F No picture, no backlight

With main board disconnected all backlights come on and stay on.


So what are the voltages on those connectors with the main board removed and backlights on.

With Main bd disconnected and BL on.

CNL802A
Pin
3 - 83.4
4 - 83.4
7 - 1.10
8 - 1.10
11 - 83.1
12 - 83.2
15 - 1.09
16 - 1.11

CNL802B
Pin
3 - 165.8
4 - 165.8
7 - 83.4
8 - 83.4
11 - 165.5
12 - 165.5
15 - 83.4
16 - 83.4

Seems like each plug has 2 sets of LEDs on it. Let me know if anything pops out at you.
Thx

[budm]

Re: Samsung UN65ES6550F No picture, no backlight

'
'If you are referring to "toon" I am not familiar with that? & It looks to some thing is killing the Pam dim signal.' Sorry that is my typo, its T-CON and PWM.

[dick_barton]

Re: Samsung UN65ES6550F No picture, no backlight

So with backlights on, the voltages read on CN802A and CN802B are:-

8 off 83V
4 off 1.0V
4 off 165V


Assuming that the 1.0v's are error feedback from the Leds then what drives the LED's. The 83V, 165V or both.???