panasonic tc-p42c2

[massieerk]

Working on a panasonic plasma tc-p42c2. The set powers up, but only displays a few pixels. If i hit menu button picture changes. when pressing VOL button i can see a distorted bar pop up and move.
I dont have original remote, but using panel buttons i have toggled between all sources( i think, hard to see writing is indeserniable) and cant get any sound.
Power supply voltages seem to check out as well power coming to SS board from SC board.
These sets are notorius for bad A boards but i dont know.
Any ideas?

[tom66]

Re: panasonic tc-p42c2

Try this:

VOL- held down on TV.

Press "0" on remote 3 times.

Release VOL-.

Wait 10 seconds.

Press red twice. Test pattern should appear. Press red each time to cycle through patterns. What does it look like?

[R_J]

Re: panasonic tc-p42c2

could be bad c2 board or bad panel (ic on ribbon from c2 board to panel) there are small heatsinks with 2 screws that hold the ribbon connector down, when the set has been on for a few minutes see if one of those heatsinks is hotter than the others.

[massieerk]

Re: panasonic tc-p42c2

Thanks for the reply guys. Took a while to get the remote.

Tom66- Tryed with remote, get nothing on display.

RJ- my C2 board has 4 heatsinks, none warm at all.

[Clydeuk]

Re: panasonic tc-p42c2

I would say you have a damaged driver ic. I would remove the 4 ribbons from the C2 one at a time and inspect the ic on each one with a magnifier, you may well find a hole in one, it's very common. There are 2 supplies to these IC's, the address supply and the low voltage supply for the ic's themselves. If one of the ic's is loading down the low voltage supply the defect can show all over the display. If you can find the shorted IC you can leave that ribbon disconnected and power up, you should get a full display with a band where the data is missing.

If you do have a failed IC unfortunately the panel is toast

[Clydeuk]

Re: panasonic tc-p42c2

This can of course be a fault on the A or one of the C boards or the ribbon cables connecting them. Visual inspection of the IC's I would say is the first step, if one is blown you will at least not be throwing any money at it on wasted parts.

[massieerk]

Re: panasonic tc-p42c2

Removed all 8 heatsinks, nothing oviously damaged. Display doesn't change much with 1 or many unhooked. I can remove connection from SS and C2...display still doesn't change much.

On my first look I thought panel, but I have little experience with plasma. They said it was playing fine and then just went out.

Second best guess- A board.

[Clydeuk]

Re: panasonic tc-p42c2

C boards don't give much trouble so yes.

[tom66]

Re: panasonic tc-p42c2

Could be SC if address/scan voltages really bad but that usually throws SOS7.

[Clydeuk]

Re: panasonic tc-p42c2

Seen a lot of people diagnose panel straight away for this kind of problem. Often correctly and I've done it myself in a busy environment. I really hope it's not as I'd like to find out the exact cause, obviously anything that affects the address could cause this as Tom says. I know up until recent models Panasonic had a fusible resistor in the 3.3? volt supply to each TCP, which would usually open if the IC failed and give you the classic black band. Newer models did away with these such that this failure would drag the supply down and affect the whole display as none of the IC's had the correct supply. I guess you could meter this to check if it's present and correct on the C boards.

[Clydeuk]

Re: panasonic tc-p42c2

By the way I'm trying to relate that one to the UK model, Is that the same as the G20 series here?

[tom66]

Re: panasonic tc-p42c2

It's 720p so closest to X20 series.

[fyca]

Deleted post - made new post here
https://www.badcaps.net/forum/showth...065#post383065