Plasma Z50PT320 Image Flickers and Goes Black

[algares]

Zenith Plasma Z50PT320 Had no picture. replaced the Logic CTRL and I got picture for 2 minutes! Now it has picture and sound but pictures flickers after a while and goes black.

I replaced the power supply, ysus, and top / bottom y scan drive with used parts from ebay.

I checked voltages coming into power supply and it reads 124, fine I guess. Checked Va and Vs on power supply and it gives me 54 for Va and 204 for Vs. Label says Va 55V and Vs 205V.

I also checked the voltage coming out of the Ysus to the Buffer boards. This reading goes all crazy with high numbers. Ranging from 400, 500, 600, etc. I replaced the battery on my multimeter just in case. The multimeter is set to VDC 600.

I did all the test with my original parts and with the replacements and I get the same crazy readings.

Please help

[tom66]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Is there a chance you could record a video of this flickering so we could see exactly what it looks like?

[algares]

Re: Plasma Z50PT320 Image Flickers and Goes Black

There you go sir,

http://youtu.be/A6w6tNJ74SY

When I move back it basically stays black for a while. Sometimes the image will come back for a second and disappears again. While doing this I can hear changes in the sound coming out of the Ysus.

[tom66]

Re: Plasma Z50PT320 Image Flickers and Goes Black

OK, and so when it does this there is no change in the Vs/Va voltages?

[algares]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Yes and at the same time I hear the sound from the ysus louder and the multimeter goes to 1 with a beep. Then back to the ranges of 400, 500, 600.

[algares]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Bump

[tom66]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Your meter is probably not internally shielded. Plasma TVs produce a lot of interference with the back cover off which could be causing problems for your meter. Any chance you can borrow a different one?

[algares]

Re: Plasma Z50PT320 Image Flickers and Goes Black

It's there a way to shield the multimeter? What about the tv not working. What could cause the image showing up for the first two minutes it's on, then it's black?

Thanks

[tom66]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Not sure how you'd shield a multimeter. A problem with the -Vy/Vsc is most likely to cause an issue in my opinion.

[algares]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Thanks a lot tom66 can you elaborate a bit on which ones are Vy and Vsc?

[tom66]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Aren't they the ones you are measuring - the ones going crazy?

[algares]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Sorry I'm a complete newbie to the plasma scene. I know the name ysus and y buffers.

[tom66]

Re: Plasma Z50PT320 Image Flickers and Goes Black

My fault, I was getting mixed up with another TV. On the top left hand edge of the plasma panel, or in the middle, there will be a sticker with "PDP50X4#######" or similar written on it, what is your "PDP" number?

[algares]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Pdp50t30010

[algares]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Tom66 why the PDP model? Thanks for your help. I'm about to put this one in the trash can!

[tom66]

Re: Plasma Z50PT320 Image Flickers and Goes Black

Sorry missed your post. It's for this.


...but unfortunately it doesn't have 50T3 alignments, so I'm going to have to work on a picture of the Y-sustain. Do you see any points marked "-Vy" or "Vsc" on the board?