Panasonic TX-26LXD80

[tom66]

Got this Panny in which would work when the frame was twisted. Backlight fine, but picture only showed when you twisted it. Otherwise, screen would be lit, but all pixels dark.

Disappointed to find a Chi-Mei panel... and the cause of the problem? Twisting the frame was a clue. It has a bad tab bond. Applying pressure to the top left tab (from the front) brings the picture back immediately.

Sienoki is going to try the fix in this video:
https://www.youtube.com/watch?v=purk_SyiT44 (similar problem, but different symptoms)

Anyway build quality is very good, with top notch caps and decent build. Lots of cable grabs and tape to secure cables and keep them out of the way. It has no T-con; that's built onto the LCD panel. Since Panasonic manufacture their own IPS Alpha display panels, it's a shame that they didn't use one of those in this TV, as it would have likely lasted longer than the Chi-Mei did.

Seeing it had a Chi-Mei panel we put two and two together and thought about the LG 26LC55 we've also got... the panels are probably the same (it used a 720p Chi-Mei too)... twisted the frame on the LG and bingo! It worked... so that's two TVs in a row with bad tab bonds.

First time I've had a look at a Panasonic LCD, and I'm reasonably impressed. Definitely built well, and likely to last, if the damn LCD had...

[bxcfilm]

Re: Panasonic TX-26LXD80

I've just found this forum, and your message. I also have a TX-26LXD80, which has developed a problem quite suddenly. I'm not a tech, but I was able to fix my 8 year old TFT monitor by replacing 4 caps last year, and it would be great if I could do the same for the TV. It's a shame the symptoms are different...

When I switch the TV on, the sound is fine, but the picture is just shades of grey, then some washed out vertical colour bars of different widths (not like a test signal). Eventually, I get a picture of sorts, which freezes while the colour washes out of it, and finally, after anywhere from 15-30 minutes, the picture comes on properly, and it's excellent after that.

The TV is under 5 years old (but no, I didn't get a 5 year warranty with it...), so I don't really want to have to get a new one.

I would appreciate any suggestions. My next move is just to take the back off and look for anything which looks scorched or burnt, or just not quite right.

[tom66]

Re: Panasonic TX-26LXD80

Tab bonds....
See my video... a THIRD 26" 720p with this problem & using the same panel!
https://www.youtube.com/watch?v=mMo3NBGLwH0

[bxcfilm]

Re: Panasonic TX-26LXD80

Many thanks. I don't want to start dismantling just now, so it'll be a while before I can confirm this (or not) in my case. Meanwhile, in your video you speculate about the cause. I think you said you had found the problem several times at the left of the top of the screen - is that right? Well, I have my TV mounted on a stand on rollers - it's a wood floor, so it moves easily. When moving the TV, I always bend down that extra bit and hold the stand, never the TV itself, but my girlfriend insists on holding the top of the TV on the left to move it. Maybe holding the TV like that can disturb a tab bond.

Just speculating ...

[tom66]

Re: Panasonic TX-26LXD80

I doubt that has anything to do with it; the cause would be more likely a mix of thermal issues and lead-free solder. The tab bonds run HOT! Some as much as 90°C.

[southboundsuarez]

Re: Panasonic TX-26LXD80

Doesnt the inverter board run along the left hand side of the panel. Seems likely that there's allotta high voltage running there. It would make sense that youd have some convection going on as the column of hot air rises just below that left tab?

[tom66]

Re: Panasonic TX-26LXD80

That could be one factor but doesn't explain failures on other panels where the inverter is on the power supply, or on both sides. The tabs themselves run extremely hot, so it's not entirely a surprise that they can fail.