Panasonic TC-P42S30 vertical multicolor lines

[Dagge]

Hi,

My less-than 2-year old TC-P42S30 just broke with symptoms that don't seem to match anything I've been finding here. I get no blinks, sound works fine, visual lines are not limited to any specific part of the display.

I took the back panel off and tried some basic troubleshooting until my multimeter died so I'll be continuing that later today. Disconnecting SN board gets me 8 blinks, disconnecting SS board gets me 6 blinks. That debugging and measuring voltages will continue later, but I just wanted to post the pictures of the display in case anyone had seen it before.

The first pic is the 'no signal' thing all messed up, but in the correct Y position, moves in Y as no signal will.

Second pic is volume bar at the bottom.

Third pic is 'menu'.

Since the panel seems fine and it's not limited to any specific area, I'm thinking A-board...

[tw2005]

Re: Panasonic TC-P42S30 vertical multicolor lines

I'd be tempted to go into service mode and try the test patterns in AGING.

[tom66]

Re: Panasonic TC-P42S30 vertical multicolor lines

My guess - sorry, panel dead. 3.3V down on A board due to panel short. Possibly fixable if 3.3V is just failed with no panel damage.
See page 32:

[Dagge]

Re: Panasonic TC-P42S30 vertical multicolor lines

I'd be tempted to go into service mode and try the test patterns in AGING.

Unfortunately the service mode screen is messed up also.

I got a new battery for my multimeter so I was able to do some measurements and it looks like V15 is shorted on the P board I only got about 39 Ohm on P11 V15 without anything connected to the P board.

With P6 and P35 connected (but not P11 or P2) I get 15.6V when turned on (Vsus solid 213). Same with P11 and P2 connected...

So, removing the P board and measuring again, I get no short....

It's getting late so this story's going to continue tomorrow

[Dagge]

Re: Panasonic TC-P42S30 vertical multicolor lines

My guess - sorry, panel dead. 3.3V down on A board due to panel short. Possibly fixable if 3.3V is just failed with no panel damage.
See page 32:

Checking the screen again it looks like there is one vertical section that's constantly dark, I'll take the bottom part apart and see if I can figure out exactly what is broken. :/

[Dagge]

Re: Panasonic TC-P42S30 vertical multicolor lines

Checking the screen again it looks like there is one vertical section that's constantly dark, I'll take the bottom part apart and see if I can figure out exactly what is broken. :/

Hm, disconnected C boards from everything but the panel. C1 board where the 'dead' vertical section is measures no shorts on C137, C138 all similar places, C2 board where I get al least sparklies on every section measures only 40 ohm on all the caps...weird. I'm wondering if I measured the right caps, these were the bigger ones on the board.

I guess the short might be on the 'better' looking side too. Is there any way of measuring the panel itself just in case a new C board might fix it?

[tom66]

Re: Panasonic TC-P42S30 vertical multicolor lines

40 ohms is enough of a short to be concerning.
Try checking with all panel ribbons disconnected but C boards in place.

[coderoman]

Re: Panasonic TC-P42S30 vertical multicolor lines

Sorry to revive an old thread, but curious if OP ever fixed the problem?

Having the same exact issue, and not nearly as experienced in component repair as OP. Used a multimeter a handful of times in my life. The TV just randomly clicked at one point and started showing all these lines.

I tried checking for bulging capacitors but all of them look fine. Based on the troubleshooting guides sticky (https://www.badcaps.net/forum/showthread.php?t=25810) it sounds like it's simply a bad LCD panel. Do you think it's worth troubleshooting or should I just sell it for parts?