Panasonic Plasma TC-P50VT25 missing colors

[tad_scsi]

Viewing example picture attached, is there anyone who can suggest where to begin to look?

My experience with Plasma TVs has largely been limited to identifying power issues causing error conditions on several sets in area.

Resetting to factory defaults did nothing to help (dang!) and condition shows when source is DVD or Cable alike.

Oddly, the on-screen menu devices supplied by TV firmware exhibit full color gradations and perfect clarity


Problem occurred when installing a APC voltage regulator, basically, just unplugging set (which was off) and plugging it into regulator.

I noticed that there was NO GROUND - someone had jury rigged an outlet using only an appliance cord to supply it. I did not note the missing ground until after putting regulator inline.

I of course, immediately switched to a grounded outlet, but when set came back on, that's what I got, though just an hour before, the picture was pretty good.

TV was operated without a ground for 3+ years, as far as I can tell. I haven't been able to move huge furniture to access and test for proper polarity yet. It is possible that it was not correct either. Suddenly switching polarity to the correct polarity has been shown to damage power supply caps on some other types of equipment before, though I'd hope the PS on this would be somewhat more robust.

Regrettable as the entire house had been properly wired sometime in the previous 20 years.

[tw2005]

Re: Panasonic Plasma TC-P50VT25 missing colors

I think it's a case of really, really bad luck. I suspect an EEPROM may have corrupted data on it.

There's 2 boards, A board (main board) and the D board . It will be one of those.

Try going into service mode and try the test patterns, it may help to isolate A or D. It did for the last guy with a 54" but he had coloured blocks across the screen at the bottom, that was D board.

[tad_scsi]

Re: Panasonic Plasma TC-P50VT25 missing colors - Solved?

Yes, really, really bad luck - but I suspected as you did - corrupted data on an EEPROM. I tried to find a complete firmware re-write, but only found some that did specific things - like adjust colors for a particular movie (AVATAR) whic would also change color settings for all modes, undesirable.

Also, since resetting factory defaults did not fix the solution, I didn't want to try the AVATAR settings, given the warning about being stuck with them.

It didn't really make sense that a polarity change (which may well corrupt data) would affect color display from external sources, but not internal.

IT SEEMS - it was corrupted data, or some gates not being properly reset:

Repeated on-off cycles did not 'fix' the problem and even letting the unit sit for hours and proactively trying to completely de-energize all the internal components (cap.s etc.) did not 'fix' it.

BUT - evidently on one such attempt where I decided to let the unit remain on for several hours, as I had tried on a previous attempt the day before., the problem fixed itself.

I am guessing that some gates were left improperly set, possibly by some electrolytic improperly discharging in a sub-section of the power system when correct polarity was initially introduced.

Eventually, some signal was sent and the gates or some other device was able to properly reset.

In any event, thank you for your time. I got really really lucky that the thing returned to normal operation without further efforts.

[tad_scsi]

Re: Panasonic Plasma TC-P50VT25 missing colors

tw2005 - thanks also for the manual... it may well be helpful down the road.