PL51D550C1G Plasma Samsung - No picture, but sound is ok

[tom66]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

It doesn't say the current, but it is a 120mm Akasa ultraquiet amber fan (2-ball bearing) 12V DC 1400RPM. I can measure the current with my multimeter if it is necessary, but I think it is very low current.

You'll need the current to determine the resistance needed.

Assuming 0.07A which is fairly typical, the fan will run quietly and have reasonable airflow at 7V, so you want 8V drop across resistor at 0.07A: 114 ohms (R = V/I), 100 ohms is close value and the resistor will dissipate about 0.49W (so select a 1W or higher resistor and place it in the airflow to help cool it.)

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Bad news: Suddenly appeared vertical bars on the screen in random colors and the TV turns off by itself after a few seconds.



What could be the problem now?

[tom66]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Can you share a picture of the fault?

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Can you share a picture of the fault?

Can you see the picture now?

[tom66]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Can't view imgur here, can you upload using "Manage Attachments" feature?

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

can't view imgur here, can you upload using "manage attachments" feature?

Sure.

[tom66]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Hmm. That is odd. Those distortion areas, are they always there, no matter the content? Do they ove? And the black bar area, is that always black, and is it fixed?

Did you unplug/replug anything before this fault occurred e.g. y-main connector or did it just happen suddenly.

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Hmm. That is odd. Those distortion areas, are they always there, no matter the content? Do they ove? And the black bar area, is that always black, and is it fixed?

Did you unplug/replug anything before this fault occurred e.g. y-main connector or did it just happen suddenly.

They are always there, no matter the content. The black bar is always there, and there is a blue bar in the left corner just like the picture. Sometimes the TV get crazy and change the channels by it self quickly and doesn't respond the remote and the panel buttons.
After a few minutes the TV turns off by itself.

PS: I unplugged the X-main board and now the TV doesn't turn off by itself, but of course, there is no picture.

[tom66]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Ok, can you supply a photo of your control board. It's the small green board in the middle of the set with the blinking green light on it.

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

ok, can you supply a photo of your control board. It's the small green board in the middle of the set with the blinking green light on it.

[tom66]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Ok,
Unplug all power to set.
Top right 2x2pin header (4 pins exposed) jumper pins 3 and 4 with a wire/HDD jumper/etc
Then disconnect right most orange "LVDS" cable.
Plug set in and take TV out of standby using remote. What do the test patterns look like?

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Ok,
Unplug all power to set.
Top right 2x2pin header (4 pins exposed) jumper pins 3 and 4 with a wire/HDD jumper/etc
Then disconnect right most orange "LVDS" cable.
Plug set in and take TV out of standby using remote. What do the test patterns look like?

I did this before but the distortions are still there

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

Here is some pictures during the patterns test:

[tom66]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

I would say about 80% control board, 20% chance plasma panel has failed (sadly Samsung panels seem to fail quite frequently.) That large chip on the control board, try pressing on it firmly and see if the problem clears. Also check all ribbon cables are seated right, especially note that long screws from some wall mounts/stands can damage these cables.

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

I would say about 80% control board, 20% chance plasma panel has failed (sadly Samsung panels seem to fail quite frequently.) That large chip on the control board, try pressing on it firmly and see if the problem clears. Also check all ribbon cables are seated right, especially note that long screws from some wall mounts/stands can damage these cables.

But the panel was ok, after I changed the Y-main board the picture was perfect! Then yesterday after I turn on my TV this problem happened. I suspect that maybe the Y-main board failed again or the X-main. Do you think this is possible?

[freakaftr8]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

I'm with Tom its most likely a control board or ribbon cable connection. I remember some of the older LG 42 inch PDP having the blue red green stripe syndrome from a bad control board processor BGA connection. That blue bar on the far left side is a clear indication of a control board fault and that would make sense it partially part of the screen is blank. Normally I would be saying bad panel but I think the control board is most likely the cause. especially since you have random pattern of distortion that are equally spaced in line with the picture

[tom66]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

But the panel was ok, after I changed the Y-main board the picture was perfect! Then yesterday after I turn on my TV this problem happened. I suspect that maybe the Y-main board failed again or the X-main. Do you think this is possible?

No, the Y-main/X-main can't cause a fault like this. I think the control board is more likely I'm just not ruling out a panel fault. Panel faults can be spontaneous (as can control board faults, for that matter.)

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

I'm with Tom its most likely a control board or ribbon cable connection. I remember some of the older LG 42 inch PDP having the blue red green stripe syndrome from a bad control board processor BGA connection. That blue bar on the far left side is a clear indication of a control board fault and that would make sense it partially part of the screen is blank. Normally I would be saying bad panel but I think the control board is most likely the cause. especially since you have random pattern of distortion that are equally spaced in line with the picture

Understood. But it could be the cause of the TV turning off by itself after a few seconds?

[rogerazambuja]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

I'm just thinking... what a bad lucky I have, because I just changed the Y-main board 2 weeks ago. My TV was working perfectly, then the control board fails? This supost control board fail could be related with the previous fail (Y-main board fail)?

[freakaftr8]

Re: PL51D550C1G Plasma Samsung - No picture, but sound is ok

I highly doubt its related. However there could be a very slight possibility