Samsung 50 plasma PN50C550G1FXZA

[freemancomputer]

I have a Samsung PN50C550G1FXZA 50 inch plasma with sound but no picture. There were black lines horizontal lines going across the screen, because of this I replaced the y buffer board. Now there is no picture, I tried putting the old board back in but nothing. There is a green light on the main logic board that flashes once every 5 seconds.

From what I have been able to find online the flashing indicates that the y board is having problems. My questions that I have is 1)Does it sound like the Y board 2)If so should I replace both the buffer and the y board or just the Y board 3)Is it worth it to replace the parts, are they likely to go bad again?

Thanks

[Hamie]

Re: Samsung 50 plasma PN50C550G1FXZA

The horizontal lines are probably caused by a bad panel.

[freemancomputer]

Re: Samsung 50 plasma PN50C550G1FXZA

That's a new one that I will have to look into. Anything I have been able to find online that had to do with black lines on a plasma tv had to do with the y board.

[Hamie]

Re: Samsung 50 plasma PN50C550G1FXZA

How many black lines are we talking about?
If you have a perfect picture apart form one or two black horizontal lines, then it's usually a panel fault.

[freemancomputer]

Re: Samsung 50 plasma PN50C550G1FXZA

There were 2-4 thin black lines.

[Hamie]

Re: Samsung 50 plasma PN50C550G1FXZA

Unplug the buffer board from the y-sus.

Check the vsc (vscan) voltage, there should be a test point on the y-sus.

Note: the y-sus shouldn't cause a horizontal black bar so if vsc is perfect and matches the panel sticker then you could repace the buffer.

[freemancomputer]

Re: Samsung 50 plasma PN50C550G1FXZA

So the readings started out really high around 400 then went down to 0 after about 30 sec. I have attached some images to make sure I am testing the right area.

Thank you for you help
Terry

https://drive.google.com/file/d/1yxx...ew?usp=sharing
https://drive.google.com/file/d/1C6T...ew?usp=sharing
https://drive.google.com/file/d/1jUv...ew?usp=sharing

[Hamie]

Re: Samsung 50 plasma PN50C550G1FXZA

That is high.
Just to make sure you're testing it properly.
DC volts, red probe to the test point, black to chassis.

Looks like you have a faulty y-sus.
The black lines however are either caused by the panel or the buffer.

If you're going to continue with the repair and swap out the boards I'd replace both.
There's a good chance the bad buffer took out the y-sus.

You can check the buffer board ICs for shorts to be positive.

[freemancomputer]

Re: Samsung 50 plasma PN50C550G1FXZA

I thought it was high as well. I'll test the buffer tonight and post findings. I can get the y-sus but the buffer is out of stock everywhere I've looked. I'll order the y-sus but hols off until I can get the buffer.

Thanks

[freemancomputer]

Re: Samsung 50 plasma PN50C550G1FXZA

The battery's I'm my meter were shot, replaced those but its only a little better. The voltage starts at 199 and over a minute it drops to 0. I attached a video that I loaded to YouTube for reference.

Terry

https://youtu.be/UOp5tnbw6is

[sordids999]

Re: Samsung 50 plasma PN50C550G1FXZA

have you tried test patterns to eliminate the panel ?

[freemancomputer]

Re: Samsung 50 plasma PN50C550G1FXZA

There's no picture right now, can that be done with no picture?

[Hamie]

Re: Samsung 50 plasma PN50C550G1FXZA

Yes although it probably won't make any difference as the voltages are dropping off.

[Hamie]

Re: Samsung 50 plasma PN50C550G1FXZA



On the control board (the one above)

See the small black square in the top right hand corner, it has 4 pins numbered 1-4.

Connect pins 3 and 4 with a piece of wire, croc clip etc

Disconnect the LVDS cable to the main board.

If you get test patterns you have a faulty mainboard.

[Hamie]

Re: Samsung 50 plasma PN50C550G1FXZA

Earlier When you checked the vsc voltages was the buffer connected?

[freemancomputer]

Re: Samsung 50 plasma PN50C550G1FXZA

Earlier When you checked the vsc voltages was the buffer connected?

no it was not

[freemancomputer]

Re: Samsung 50 plasma PN50C550G1FXZA

That test didn't change anything

[Hamie]

Re: Samsung 50 plasma PN50C550G1FXZA

Ok what's the vsc voltage with the buffer connected?

[freemancomputer]

Re: Samsung 50 plasma PN50C550G1FXZA

The voltage was the same starting at 199 then dropping off.

[Hamie]

Re: Samsung 50 plasma PN50C550G1FXZA

What's the ve voltage on the xmain (zsus)