Philips 42PF9966/37 Plasma No Pic

[kevinm34232]

I just picked up this old plasma with Chassis FTP2.2U AA, which is Samsung based. It turns on but all I see is colored lines where any display would be. If I adjust the volume I can see where the OSD would be but it is completely distorted. I was not able to get volume because I cannot see what input Im on, but it seems like everything else is OK.

I did a quick check of voltages on PS:

Measured----Sticker
VS = 170V------(170V)
VE = 155V----- (155V)

VA = 157V----- (70V)
VSC= -116V---- (-55V)

Any thoughts on the VA and VSC being way off?

[tom66]

Re: Philips 42PF9966/37 Plasma No Pic

If your Va is truly 157V, the plasma display is well and truly fried.

[kevinm34232]

Re: Philips 42PF9966/37 Plasma No Pic

I made a mistake there was a solder pad next to where the VA wires are and I assumed that was test point. VA is measuring 71V.

However the VSC measured at "T-VSCAN" point, is measuring the -116V. Is that the right test point?

[tom66]

Re: Philips 42PF9966/37 Plasma No Pic

Can you show a picture of the problem? Poor Vscan could cause that.
Also, try the test pattern generator: https://www.badcaps.net/forum/showpo...61&postcount=2

[kevinm34232]

Re: Philips 42PF9966/37 Plasma No Pic

This is when I hit Menu button, otherwise it's just some lines in the top left of screen.

[kevinm34232]

Re: Philips 42PF9966/37 Plasma No Pic

Poor VScan is caused by what? Ill do that test pattern soon I have to dig down into it to get to the logic board.

[tom66]

Re: Philips 42PF9966/37 Plasma No Pic

Poor Vscan can be cased by bad Y-buffer or fault on Y-sus or sub power/main power board (if that generates -Vsc). Check with buffers removed. Does the Y-sus power connect include -Vscan/-Vsc pin? If so, then the sub power/main power may cause the fault, try w/o Y-sus connected.

[kevinm34232]

Re: Philips 42PF9966/37 Plasma No Pic

This is the logic board, any idea how to do the test patterns on this one?

http://www.shopjimmy.com/philips-996...ctrl-board.htm

[tom66]

Re: Philips 42PF9966/37 Plasma No Pic

I don't see any way to do test patterns on that board, very old school tech there.

[kevinm34232]

Re: Philips 42PF9966/37 Plasma No Pic

I disconnected Y-Main and -Vscan went normal (-55V). So I delved further into the TV and the bottom chip on the lower buffer had a slight bubble. It showed short as did the 3 mosfets on the Y-Main. Everything else seems OK.

Is it likely I can get away with replacing the lower buffer and those 3 (or whichever one is shorted) ICs?