Samsung UN55D7000 clicks but does not turn on

[Uzrnaim]

Re: Samsung UN55D7000 clicks but does not turn on

Just above where the mains goes into the power board there is a black relay lying on its side, I have had this cause exatcley the problem you have , it had burnt contacts.

So you're saying the relay itself may be at fault?

How would I go about this, is it repairable internally or only replaceable?
Can it be temporarily bypassed or am I going to blow something up in bypassing it?

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

The power relay is turned on by the ps-on signal from the Main board, so is the PS-on dcv steady or it is going up and down.
Read my post 8.
What dcv do you have between the two legs of the main filter cap when you run the power supply-LED driver board by itself?

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

What is YOUR power supply board P/N BN44-xxxxxx?

[Uzrnaim]

Re: Samsung UN55D7000 clicks but does not turn on

What is YOUR power supply board P/N BN44-xxxxxx?

By board P/N is BN44-00428A

"The power relay is turned on by the ps-on signal from the Main board, so is the PS-on dcv steady or it is going up and down.
Read my post 8.
What dcv do you have between the two legs of the main filter cap when you run the power supply-LED driver board by itself?"

My pins measure as follows:
1 5.3
2 0
3 5.09
4 0
5 0
6 0
7 12.82
8 0
9 12.82
10 12.8
11 17.16
12 4.8
13 17.16
14 0
15 0
16 0
17 5.39
18 5.4
19 5.3
20 3.38
21 N/A
22 N/A

Across the main capacitor I'm seeing 388.7v

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

By board P/N is BN44-00428A

"The power relay is turned on by the ps-on signal from the Main board, so is the PS-on dcv steady or it is going up and down.
Read my post 8.
What dcv do you have between the two legs of the main filter cap when you run the power supply-LED driver board by itself?"

My pins measure as follows:
1 5.3
2 0
3 5.09
4 0
5 0
6 0
7 12.82
8 0
9 12.82
10 12.8
11 17.16
12 4.8
13 17.16
14 0
15 0
16 0
17 5.39
18 5.4
19 5.3
20 3.38
21 N/A
22 N/A

Across the main capacitor I'm seeing 388.7v

The relay is on otherwise you will not have that boosted voltage.
I cannot tell you what you are missing due to no pin names for all those pin.
But since you are getting the boosted voltage without the main board then you should see the backlights.

[Uzrnaim]

Re: Samsung UN55D7000 clicks but does not turn on

The relay is on otherwise you will not have that boosted voltage.
I cannot tell you what you are missing due to no pin names for all those pin.
But since you are getting the boosted voltage without the main board then you should see the backlights.

So that means that the backlight is most likely the culprit then?

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

So that means that the backlight is most likely the culprit then?

So where are the names of each pin that I requested?
Are the readings on the pins without the cables connected between the power supply and the main board?

[Uzrnaim]

Re: Samsung UN55D7000 clicks but does not turn on

So where are the names of each pin that I requested?
Are the readings on the pins without the cables connected between the power supply and the main board?

The names of the pins are in a PDF which you had linked earlier in this thread, an image of which I'll share below.

I took those measurements without any boards connected to the power supply board. According to that pdf, the backlights should definitely be on if the main board isn't connected to the power supply.

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

This is the format we alwyas for when report the readings on the pins:
We are asking for the Voltage readings on the power supply board pins without any other board connected to the power supply board.
Very simple for example CN201 OF THE MAIN BOARD:
1: B5V = 5.3v
2:SW_PWR_OUT = 0V
3 5.09
4 0
5 0
6 0
7 12.82
8 0
9 12.82
10 12.8
11 17.16
12 4.8
13 17.16
14 0
15 0
16 0
17 5.39
18 5.4
19 5.3
20 3.38
21 N/A
22 N/A
But not only that, that CN201 is the connector on the main board. That link lists the pin names of the main board.
We need the reading on the power supply board.

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

BN44-00428A provided by shopjimmy.
As you can see what the pin names on the power supply board are for CNM803 hwich goes to the main board.
Pin 1: OD_LEVEL = ???V
Pin 2: P_DIM4 = ???V
AND ON AND ON AND ON.
It is hard enough to troubleshoot complex electronics without having the real unit in front of us to look, so good clear and correct information must be provided to us for you to get proper helps.

[Uzrnaim]

Re: Samsung UN55D7000 clicks but does not turn on

BN44-00428A provided by shopjimmy.
As you can see what the pin names on the power supply board are for CNM803 hwich goes to the main board.
Pin 1: OD_LEVEL = ???V
Pin 2: P_DIM4 = ???V
AND ON AND ON AND ON.
It is hard enough to troubleshoot complex electronics without having the real unit in front of us to look, so good clear and correct information must be provided to us for you to get proper helps.

When I measured them I actually measured off of the power board not the main board, I didn't realize the numbers weren't the same between the two. Doh.
The names in the image you linked line up with the order I took the measurements, if that helps. So Pin1 is the OD_Level, 2 is P_DIM4, 3 is OD_On/Off, etc. etc.

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

The pictures I provided is for the BN44-00428A that you told me is what you have so, verify and see if it matches your board and then take the readings..

[Uzrnaim]

Re: Samsung UN55D7000 clicks but does not turn on

1 Od_ Level 5.3
2 P_DIM4 0
3 OD_ON/OFF 5.09
4 P_DIM3 0
5 GND 0
6 P_DIM2 0
7 B13v 12.82
8 P_DIM1 0
9 B13v 12.82
10 B13v 12.8
11 Vamp 17.16
12 BLU ON/OFF 4.8
13 Vamp 17.16
14 GND 0
15 GND 0
16 GND 0
17 B5v 5.39
18 A5v 5.4
19 B5v 5.3
20 Power ON/OFF 3.38
21 N. C
22 N. C

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

"12 BLU ON/OFF 4.8" So you do have Backlights ON command signal from the main baord BUT you do noy have any Dimming control signals at all, the P_DIM 1~4 are all 0V, 0V will cause no backlights.
We need to see the pictures of the whole back side of the TV to see how all the boards are connected together.

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

You did not see the backlights even flash on for seconds?

[Uzrnaim]

Re: Samsung UN55D7000 clicks but does not turn on

You did not see the backlights even flash on for seconds?

Nope, not even a flash.

[budm]

Re: Samsung UN55D7000 clicks but does not turn on

Per fast track, you will need to find out if it is LED problem or LED drive circuit problem next.
Then there is problem with power relay cycling which is another problem by itself due to the fact that is controlled by the main board.
The power supply-LED driver board has its own force on resistors to allow you to narrow down the problem quicker by disconnecting the cables between the two boards, the older TV you will have to add the resistors yourself to force on the power supply.

[Uzrnaim]

Re: Samsung UN55D7000 clicks but does not turn on

Alright, so I ordered a replacement power supply after my failed attempt to bring the original back to life. The replacement power supply now powers the backlights when the main board is disconnected, but upon re-connecting the main board the relay again starts clicking. Is there some kind of reset I can do on the main board?

[Oglon3r]

Re: Samsung UN55D7000 clicks but does not turn on

I always go with this guide by far what has helped me the most.
https://www.badcaps.net/forum/showthread.php?t=25810
After checking your problem it seems that you had both a bad power supply and a bad motherboard at the same time.
Were you in a thunderstorm by any chance?
Multiple component failure is usually indicative of it.
Anyway since you get back light now but no image. All it leaves is your motherboard itself.
Finally can you double check if you connected all wires correctly?
Thanks!

[magladry]

Re: Samsung UN55D7000 clicks but does not turn on

Sorry, a bit of a noob here. I have the same TV and it has a similar behavior, when I plug in power cable the Samsung logo comes on, I hear a click then it reboots and repeats. When I disconnect the main board and plug the power cable in, the backlights come on but flash. Does this mean the issue is with the SMPS board? Should the backlights turn on and remain on?