Samsung UE32F6800SB

[Billsy]

Hi everyone this is my first proper post so please be gentle
Looks like a great community.

I have a Samsung UE32F6800SB LED TV that is refusing to power up. The standby light is flashing. The first test I did was to disconnect the main board from the power board, then when power was connected, the backlight came on so I would assume the main board is at fault. However the backlight is flickering quite badly so maybe the power board is where I should start? Any thoughts?

Looking at the voltages (with main board connected), it appears to be constantly power cycling see below:

1 NC__________0.2 - 3.3
3 OD_ON/OFF___0.08 - 3
5 GND_________0
7 B13V________0 - 8.8
9 B13V________0 - 8.8
11 Vamp_______0 - 8.8
13 Vamp_______0 - 8.8
15 GND________0
17 B5V_________0 - 5.3
19 B5V_________0 - 5.3

2 PWM_DIM4____0.002 - 0.007
4 PWM_DIM3____0.002 - 3.2
6 PWM_DIM2____0.002 - 0.007
8 PWM_DIM1____0.002 - 0.007
10 NC__________0 - 0.004
12 BLU_ON/OFF__0 - 0.127
14 GND_________0
16 GND_________0
18 A5V_________5.3
20 PS_ON_______0.25 - 3.3

Please help
Many thanks
Billsy

[Andrew F. Ali]

Re: Samsung UE32F6800SB

With the Main Bd. disconnected and plugging into the ac, if the Backlights come on but is flashing then you have a backlights problem, too.

[Billsy]

Re: Samsung UE32F6800SB

Thanks Andrew. Yes I should check the LED's. I've just finished checking all the caps and they are fine.
Cheers

[budm]

Re: Samsung UE32F6800SB

That power supply/LED driver board has 4 boost converter for four sets of LED string.
What is the board P/N? BN44-????? I cannot read it from your pictures.
You need to inspect the solder joints on all the legs of the transformers, especially on those rivet feed-through joints.

[Billsy]

Re: Samsung UE32F6800SB

Thanks budm I will check that later. Power board number is BN44-00620A. Main board is BN94-06737F
Thanks for your time

[Billsy]

Re: Samsung UE32F6800SB

Ok all the transformer legs look fine and have continuity with PCB traces. The backlight LED's all seem fine. I can illuminate them one by one with my meter in diode mode. I have checked all the diodes on the board and they are working as they should.

I think I'm going to look for a replacement board but which one should I replace? Power?

Many thanks guys

[Billsy]

Re: Samsung UE32F6800SB

Quick update. Replacing the power board fixed this tv.

Thanks for your help

BR

[budm]

Re: Samsung UE32F6800SB

Thanks for the follow-up.