PL51D550C1G Plasma Samsung - No picture, but sound is ok

[rogerazambuja]

Hi Guys. I have a PL51D550 Samsung Plasma TV model (Brazilian version of PN51D550). Some days ago I was watching tv, then I heard a loud "shot" coming from the set and the picture was gone. Only sound works now.
I checked all voltages on every board according to a video on internet and they are ok. Visually there is no blowed capacitor, and the led on logic board is blinking indicating that everything is fine. Any advices?

[tom66]

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

Please supply pictures of the parts in the chassis. https://www.badcaps.net/forum/showthread.php?t=39740

[rogerazambuja]

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

As soon as I arrive at home I will take some pictures. Tks

[rogerazambuja]

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



Here are some pictures of all the boards. I took the pictures with my phone's camera, so if it is not good let me know. I will take better pictures with a better camera with macro function asap.

[tom66]

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

Pictures are good, thanks.

Do you have a digital multimeter available?

On the power board (http://i.imgur.com/h8FhVdI.jpg) there are points marked VS-TP and VA-TP.

Please check the voltage on these points. Use DC volts (highest range if manually ranging) and place the red probe on the point, black probe on the chassis.

Note what you get with the set plugged in and working.

[rogerazambuja]

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

Pictures are good, thanks.

Do you have a digital multimeter available?

On the power board (http://i.imgur.com/h8FhVdI.jpg) there are points marked VS-TP and VA-TP.

Please check the voltage on these points. Use DC volts (highest range if manually ranging) and place the red probe on the point, black probe on the chassis.

Note what you get with the set plugged in and working.

Hi Tom. I already checked these points, but I did again right now, VS is 203V and VA is 56V.
There is a "stamp" on TV saying the correct voltages, and it says: VS 205V, VA 58V, VSC -187, VE 80. I think that these variations are normal, right?
What could be wrong? Is it possible that the panel is broken, even if visually it seems ok? Is it normal the led on logic board blinks indicating that everything is ok even when some board is the problem?
Sorry for bad english and so many questions, I'm trying to explain with details. Thanks a lot for helping.

[rogerazambuja]

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

I forgot to mention... I tried a "self test" too. On this test you disconnect the cable that connect main board and logic board, and put a jumper in the logic board, then it is supposed to show some picture patterns on screen. It didn't work, screen remains off.

[mmartell]

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

Did you check fuses on the Y and X Boards ?

[tom66]

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

I'd check in a dark room, see if you can see a slight glow from the panel.
You can check Vsc and Ve on Y-main and X-main respectively. (Vsc may be marked Vscan.)
There is also usually a fuse on the E/F buffer boards which should also be checked.

[rogerazambuja]

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

Did you check fuses on the Y and X Boards ?

To be honest I didn't find any fuses on both boards. If you guys with more knowledge could mark the fuses on the pictures i'll be grateful.

I'd check in a dark room, see if you can see a slight glow from the panel. You can check Vsc and Ve on Y-main and X-main respectively. (Vsc may be marked Vscan.) There is also usually a fuse on the E/F buffer boards which should also be checked.

Which one is the "E/F buffer board"? I will test if I can see a slight glow from panel as soon as a arrive at home.

[tom66]

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

E/F buffer boards are at the bottom of the set. There is a heatsink covering them. Fuse will typically be a small white surface-mount device, often with gold or silver endcaps.

I don't think there are any fuses on the Y-main or X-main on this set.

Note: You can take the heatsink off but you absolutely MUST install it before powering the TV up, as otherwise damage can occur to the plasma panel.

[rogerazambuja]

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

I checked with a multimeter the fuse on F Buffer board and it is ok. I will check now VS, Ve and the panel...

[rogerazambuja]

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

I'd check in a dark room, see if you can see a slight glow from the panel.
You can check Vsc and Ve on Y-main and X-main respectively. (Vsc may be marked Vscan.)
There is also usually a fuse on the E/F buffer boards which should also be checked.

How do I check Vsc and Ve with a digital multimeter? Same way I checked VS and VA?

[tom66]

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

Yep, same way.

[rogerazambuja]

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

I checked. VSC is around -187 and VE are changing between 70~72. The stamp on tv says that VSC should be -187 (and it is) and VE should be 80. So VE is the problem?

PS: I just checked the screen right now and is completely black.

[tom66]

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

Ve is ok, a slightly low voltage is acceptable if the image is not on.
On the X-main (http://i.imgur.com/9TSFJGL.jpg), there are three or four large red capacitors. Right next to each other, top left of board. Can you measure the voltage ACROSS these?

[rogerazambuja]

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

Ve is ok, a slightly low voltage is acceptable if the image is not on.
On the X-main (http://i.imgur.com/9TSFJGL.jpg), there are three or four large red capacitors. Right next to each other, top left of board. Can you measure the voltage ACROSS these?

Yes. I will check right now...

[rogerazambuja]

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

How do I check these capacitors? I used DC Volts at maximun scale (1000V) and I tried black probe on SVC_Ground and the red probe on both sides (first one side, after the other side) of capacitor. Multimeter went crazy with numbers on display. What I did wrong?

[tom66]

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

Hm, do you have an oscilloscope available?
Some meters can't handle the electrically noisy environment of a plasma display (they produce a lot of RF) so this can cause them to go a little crazy.

[rogerazambuja]

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

Hm, do you have an oscilloscope available?
Some meters can't handle the electrically noisy environment of a plasma display (they produce a lot of RF) so this can cause them to go a little crazy.

No, I don't have

What else I can do to troubleshoot my tv?