Samsung UN46D6900WF no picture

[dzavadil1]

Samsung UN46D6900WF need a little help.

I am unsure if I should start a new thread or try and get some help here where there is a lot of the same info but a little different.

I can provide pictures if need be but I have confirmed that the power supply board is the same as well as the main-board.

My issue is relay clicking, led flashing, no picture, no back-light, in a continuous cycle that even continues after the unit is unplugged briefly. Back light comes on solid when the main-board is disconnected.

Voltage readings are off from reported above and are as follow.

1. OD_LE 2.385
2. PWM4 .89
3. OD_ON 2.669
4. PWM3 .89
5. GND .5mV
6. PWM2 .89
7. GND .5mV
8. PWM1 139 mV
9. B13V 12.81
10. B13V 139 mV
11. VAMP 12.81
12. BLU .2 mV
13. VAMP 12.81
14. GND .1 mV
15. GND USED AS GROUND
16. GND .1 mV
17. B5V 5.35
18. A5V 5.35
19. B5V 5.35
20. PS 3.33

Readings were taken with the Main-board attached, between power cycles.

Any guidance from here would be much appreciated.

[dick_barton]

Re: Samsung UN46D6900WF no picture

You appear to be missing the backlight on control voltage (BLU).
Also Pin 10 B13V is it really 139mV!!!

If you disconnect the main board from the power supply do the backlights come on?

[budm]

Re: Samsung UN46D6900WF no picture

Must be measurement error because the B13v and AMP are from the same power supply.
May be the pin are counted wrong?

[Davi.p]

Re: Samsung UN46D6900WF no picture

HI, the better thing was to open a new thread since OP had a panel fault (swapping the ribbon position have fried also tcon, ahaha..) you have for what i can understand a bad mainboard. To be sure disconnect tcon and see if the backlight, relay and sound behaviour is the same..

[dzavadil1]

Re: Samsung UN46D6900WF no picture

Thanks for the Quick replies!

I rechecked pin 10. 13v 12.81 so it looks like I did count wrong.

Rechecked BLU and most of the other pins and they were all correct.

With the main board disconnected the back light is on and solid. Relay clicks and stays.

With the TCon unplugged it shows the same symptoms.
So problem with the main-board. Looks like I can pick one up on electronics bay.

Anything I can look at as far as a component repair. Anything else you guys could recommend or should I just bite the bullet and pick up a different main board. I checked the 4 voltage regulators I could see 2 were the same 17-33z 1141fg 3.3v and 2v The others reported 22 mv and 0, 17-33z 1131DG

Do you guys think there is any further diagnostic to be done to try and repair the main board or should I just bite the bullet and buy the different main board.

[dick_barton]

Re: Samsung UN46D6900WF no picture

Anything I can look at as far as a component repair. Anything else you guys could recommend or should I just bite the bullet and pick up a different main board. I checked the 4 voltage regulators I could see 2 were the same 17-33z 1141fg 3.3v and 2v The others reported 22 mv and 0, 17-33z 1131DG

If you could list in table form the regulators with their pin voltages could be useful along with some photo's.