Samsung PN43D450A2D No Video

[phantom715]

I have had this TV for almost two years. It worked fine for a while but a month ago it was being watched and then the picture just went black. Audio worked fine, TV responded to remote signals; switched inputs, changed volume. For a while when troubleshooting it, there was an instant of RGB colored static when turning it on. Now there's nothing at all when turning it on, but the audio works fine, and it still recieves signals from the remote. I have tried to find the answer online, and most of what I've found is when the whole TV won't turn on, or related to blown capacitors. I've opened it up and looked at the components & capacitors and I don't see anything obvious. I have some electrical experience, but I'm not sure what I'm looking for. I received this as a prize, so I have no receipt or warranty, and I don't have the money to have it repaired or replaced. Any help would be greatly appreciated.

[tom66]

Re: Samsung PN43D450A2D No Video

I repaired one of these a while a go. (PS43D450 -- European model and one of its predecessors, the PS42B450.)

On the left hand side of the TV (looking at the back as in your photos) you have the Y-buffer (green board) and Y-main (orange board.)

Centre of the TV is the power supply board.

Right hand side orange board is the X-main.

The smaller remaining green board is the logic/control board and the larger one is the main board (or AV board.)

A very common failure on this model is a failure of the X-main board, though the Y-main also fails as well.

Please read through this guide to see if you get test patterns:
https://www.badcaps.net/forum/showpo...61&postcount=2

If not, you will need a digital multimeter to do the rest of the repair work.

[phantom715]

Re: Samsung PN43D450A2D No Video

Awesome; thank you! I will look at it and let you know what I find.

[phantom715]

Re: Samsung PN43D450A2D No Video

I followed the instructions you gave at: https://www.badcaps.net/forum/showpo...61&postcount=2 and I get the RGB static again when turning it on; I tried a couple of times. I do have a multimeter.

[tom66]

Re: Samsung PN43D450A2D No Video

Do you ever have a solid colour screen?
It should look like this:
http://www.youtube.com/watch?v=JCtF5...ature=youtu.be

[phantom715]

Re: Samsung PN43D450A2D No Video

No, nothing like that.

[tom66]

Re: Samsung PN43D450A2D No Video

OK, at this point, I would suggest you find a multimeter so you can make some basic tests.

[phantom715]

Re: Samsung PN43D450A2D No Video

I've got one.

[tom66]

Re: Samsung PN43D450A2D No Video

I can't seem to load your pictures?

[phantom715]

Re: Samsung PN43D450A2D No Video

Sorry; Google screwed up my pictures.

Main:


Left:


Center:


Right:

[tom66]

Re: Samsung PN43D450A2D No Video

Can't see your X-main but no worry -- I can work without that at the moment.

On the power supply board (middle board) you will see two points. Vs and Va. They are bare metal pads.

One of the stickers on the back of the plasma panel will indicate what you should see for Vs and Va, the two main voltages the plasma panel requires.

The Vs should be around 200~210V, and the Va 50~60V for this particular panel. Set your meter to the highest DC range to measure it (do not use the AC range.)

[phantom715]

Re: Samsung PN43D450A2D No Video

Sorry, I've been without internet for the last 36 hours. I tested the voltages. The Vs holds steady at only 11vdc, and the Va holds at 2vdc. I assume that this is my problem.

I'm including a larger image of that board below. Photobucket keeps rotating it. It should be rotated 90 degrees clockwise.

[randtek]

Re: Samsung PN43D450A2D No Video

You will need to test those voltages right as the TV powers up. The way I do it is to turn the TV ON, unplug the A/C cord from the rear of the set, not the wall. Put your meter lead on the test point, then plug the A/C cord back into the rear of the TV, while watching the voltage. It will probably come up, then start going back down. Repeat for both the VS and VA voltages. Reply back with the results. Tell us the highest voltage on each reading, and if it starts to go down after initially coming up.

[phantom715]

Re: Samsung PN43D450A2D No Video

I tried again, and the Vs starts at the 205vdc that it's supposed to, and then slowly drops to the 11vdc. The Va starts at the 58vdc it's supposed to, and then drops to the 2vdc. This happens both when I plug it in, and when I turn the unit on.

[tom66]

Re: Samsung PN43D450A2D No Video

OK, in a dark room, can you see a glow or flicker from the screen when the TV is first powered up?

[phantom715]

Re: Samsung PN43D450A2D No Video

When it is first powered up, it flashes static, and then all glow/light fades away quickly.

[techman365]

Re: Samsung PN43D450A2D No Video

I have this same problem with voltages dropping. Can you tell me what is causing it.

[tom66]

Re: Samsung PN43D450A2D No Video

Failed Y-main or X-main board.

[techman365]

Re: Samsung PN43D450A2D No Video

Thanks

[phantom715]

Re: Samsung PN43D450A2D No Video

Failed Y-main or X-main board.

So what would be my next step? Is this something that I might be able to fix?