Myrica p42-2H green shadows

[nostrike]

Hey all.
I have a 42" Myrica P42-2H Plasma TV,
that have green shadows.
See my picture.



Does anyone have a guess what is wrong?

Best regards
Dan

[tom66]

Re: Myrica p42-2H green shadows

I would guess a T-con/control board issue.

It could also be a problem with the -Vy or Vsc voltages.

[nostrike]

Re: Myrica p42-2H green shadows

Hey Tom66.

It is random, if that has something to say.
Sometimes it can run for hours without the green shadows,
other times it is there after 2 minutes.

[tom66]

Re: Myrica p42-2H green shadows

Sounds a lot like a dodgy potentiometer (i.e. voltage adjustment) to me. Start by disassembling the set and taking pictures. I know Fujitsu at some point made their own plasma panels, so it could be Fujitsu internals, which I don't know much about, but it should be possible to figure it out. Or it could be a Samsung or LG panel.

[nostrike]

Re: Myrica p42-2H green shadows

I will take pictures and upload them as fast as possible.
Thanks for helping so far.

[tom66]

Re: Myrica p42-2H green shadows

I forgot to ask. Does it just "snap", suddenly there are green shadows, or does it slowly get worse?

[nostrike]

Re: Myrica p42-2H green shadows

It does slowly get worse. Sometimes it is almost totally green. Today it froze for the first time (picture) then I shut it off with remote and turned it on again, and it worked again, but still with green shadows.

[tom66]

Re: Myrica p42-2H green shadows

The fact that it froze makes me lean more towards it being a control board issue but I'd take a stab at the -Vy/Vsc first as I have seen the issue before with LG plasmas.

[nostrike]

Re: Myrica p42-2H green shadows

Hey Tom66, here are the pictures :


[img=http://img94.*************/img94/771/dsc0077zv.th.jpg]
[img=http://img641.*************/img641/7501/dsc0076ann.th.jpg]
[img=http://img96.*************/img96/621/dsc0075cn.th.jpg]
[img=http://img163.*************/img163/6159/dsc0074vr.th.jpg]
[img=http://img716.*************/img716/7184/dsc0073rrq.th.jpg]
[img=http://img525.*************/img525/6741/dsc0072ecc.th.jpg]
[img=http://img849.*************/img849/7087/dsc0071mt.th.jpg]
[img=http://img513.*************/img513/8259/dsc0070pqz.th.jpg]

[tom66]

Re: Myrica p42-2H green shadows

Looks like a Samsung panel.

It looks like the power supply generates most of the output voltages for the plasma panel. (Newer PDPs put the sub-PSUs on the sustain boards.)

Are there any markings for the Vsc or Vset voltages on the power supply output?

Can you test them with a digital multimeter?

[nostrike]

Re: Myrica p42-2H green shadows

There is many markings, hvor you can turn blue things with a screwdriver.
There is VR101, D3V3(VR401), VA(VR301), VSCAN, VE_VR531, VR501(VSET)

The power supply is Samsung V4C
I have a digital multimeter.
How do I test them ?

[tom66]

Re: Myrica p42-2H green shadows

We are most interested in Vscan and Vset - are there test points for these on the power supply?

[nostrike]

Re: Myrica p42-2H green shadows

Do you mean these :

[tom66]

Re: Myrica p42-2H green shadows

Yep, I think those gold test points. Test with black probe in frame, red probe on test pad. The readings should be within +/-0.5V of the panel sticker. Test before it goes wrong, and after it goes wrong.

[nostrike]

Re: Myrica p42-2H green shadows

I am from Denmark, are pretty good to english, but I do not understood that with "in frame" ?

[tom66]

Re: Myrica p42-2H green shadows

I am from Denmark, are pretty good to english, but I do not understood that with "in frame" ?

Sorry - I mean black probe on an exposed part of the metal frame of the TV - the chassis, if you will. This is your ground point for all measurements.

[nostrike]

Re: Myrica p42-2H green shadows

Vscan -191,4 (sticker says -190)
Vset unstable 195, 47, 87 (alot of numbers) (sticker says 195)

So something must be wrong with Vset ?

[tom66]

Re: Myrica p42-2H green shadows

Vscan is a little too low, but probably not your main problem. When the picture is good, is Vset good? Try turning the Vset a quarter turn clockwise, and a quarter turn counterclockwise, this might get rid of some dust inside of it. If you have some contact cleaner, try using this on the adjustment, turn it a bit to get the cleaner inside the potentiometer.

[nostrike]

Re: Myrica p42-2H green shadows

Some time since the picture were good. It got worse with time. Just started it up and green shadows and still unstable after turning it.

Just turned it on with my xbox 360. God picture, but still unstable Vset

[tom66]

Re: Myrica p42-2H green shadows

Try turning it a whole turn downwards. Mark with a marker pen the original position. See if it remains stable (but the picture may be poor with low Vset, generally it will tend to "stick" and not erase completely frame by frame.)