Panasonic TX-P42U30B strange behaviour and now dead

[tom66]

My bedroom TV was doing something weird last night, and woke me up.

Its relay was clicking on and off every 10 seconds, but the set was not turning on. It would function fine if turned on using the remote, and stopped when the power button on the side was used to turn off the set. When doing the relay cycling, the red light would blink as if it was picking up a remote control signal - but it would never actually turn on.

Now, the TV is not turning on at all. The power light is locked green and the relay is cycling periodically. Pressing the power button on the remote causes the light to turn off, and then the set behaves as if it's completely switched off.

I don't think this is a sustain IGBT failure, I suspect more likely main board related, unfortunately. :/ I do know that the 15V main supply is not turning on, because I added a fan to that rail (to keep SN board cool), and the fan is not heard to spin up. I will diagnose it when I have some more space to take apart.

Both my Panasonic TVs have had strange failures recently, and they are both over five years old. It's really disappointing if this points to a consistent failure mode. The bedroom TV has less than 10,000 hours usage.

[tom66]

Re: Panasonic TX-P42U30B strange behaviour and now dead

The TV powered on, but it's becoming slow and freezing in menus and in the EPG.

I think I know this fault - it's exactly the same as dead flash memory that I've encountered before on other products. When flash memory becomes bad, it can take some time to read sectors, or reads can fail altogether. This leads to the symptom of the TV crashing or taking ages to complete actions. The watchdog will sometimes step in, causing the Linux CPU to reboot.

Sigh. This has been known about for years before this TV was made. But flash memory faults affect everything from TVs to Teslas so I guess the industry won't learn!

[Battle1066]

Re: Panasonic TX-P42U30B strange behaviour and now dead

The TV powered on, but it's becoming slow and freezing in menus and in the EPG.

I think I know this fault - it's exactly the same as dead flash memory that I've encountered before on other products. When flash memory becomes bad, it can take some time to read sectors, or reads can fail altogether. This leads to the symptom of the TV crashing or taking ages to complete actions. The watchdog will sometimes step in, causing the Linux CPU to reboot.

Sigh. This has been known about for years before this TV was made. But flash memory faults affect everything from TVs to Teslas so I guess the industry won't learn!

Well between our two sets we could do a case of fault finding by subitution if your in Leeds as I'm currently in Newcastle, if your interested?

[freakaftr8]

Re: Panasonic TX-P42U30B strange behaviour and now dead

Degradation of silicon probably.

This could be the new norm for Panasonic plasmas of this vintage. I have seen this twice myself. One was a th-42px77u and a tc-p50ut50

[tom66]

Re: Panasonic TX-P42U30B strange behaviour and now dead

Well between our two sets we could do a case of fault finding by subitution if your in Leeds as I'm currently in Newcastle, if your interested?

Probably not, I'd rather not end up with two broken sets!
I managed to fix my set temporarily by doing a factory reset. It might help fix the flash sector faults.

[tom66]

Re: Panasonic TX-P42U30B strange behaviour and now dead

Four days in and the TV is still working after this, no more strange behavour so it looks like it's fixed.

[tw2005]

Re: Panasonic TX-P42U30B strange behaviour and now dead

Four days in and the TV is still working after this, no more strange behavour so it looks like it's fixed.

Amazing

[syaoran123]

Re: Panasonic TX-P42U30B strange behaviour and now dead

The U series is terrible in these sets. Colours are washed out, even in a dark room.

[RJARRRPCGP]

Re: Panasonic TX-P42U30B strange behaviour and now dead

Degradation of silicon probably.

I think that was the cause of a Windows 7 installation failing real early on, before the first reboot, with error message (in a box) "Setup cannot install required files"(or similar)
(It looked like it completed extracting files though.)

(Because of a faulty "Gorilla Drive" USB stick drive) (Used to install Windows from)

(unless it was a shit solder joint...)

I hate silicon degradation! Reminds me that my pile of dog shit Pentium E2180 (poor man's Core 2 Duo "Conroe") probably had some of that! But, that's long gone now! It still worked fine at stock or a little OC, when I dumped it...

[tom66]

Re: Panasonic TX-P42U30B strange behaviour and now dead

The U series is terrible in these sets. Colours are washed out, even in a dark room.

That certainly isn't true for the U30B. The TV has excellent picture quality and brightness, despite only using 200 watts from the wall. Excellent black levels and fairly minimal image retention too. It's a prime example of Panasonic's 2011-2013 NeoPDP tech which is very good.

[tw2005]

Re: Panasonic TX-P42U30B strange behaviour and now dead

That certainly isn't true for the U30B. The TV has excellent picture quality and brightness, despite only using 200 watts from the wall. Excellent black levels and fairly minimal image retention too. It's a prime example of Panasonic's 2011-2013 NeoPDP tech which is very good.

I actually find the image on th eU30 to be brighter and crisper in comparison to the upmarket st, gt and vt with the anti-glare coating.

[tom66]

Re: Panasonic TX-P42U30B strange behaviour and now dead

I actually find the image on th eU30 to be brighter and crisper in comparison to the upmarket st, gt and vt with the anti-glare coating.

Yeah I'm looking out for a U50B to replace the ST50B in the living room.
I don't use the 3D features on the ST and I think the brighter U50B would suit me well...ST50 is compromised on all except 3D mode (probably to improve panel lifetime).

[syaoran123]

Re: Panasonic TX-P42U30B strange behaviour and now dead

That certainly isn't true for the U30B. The TV has excellent picture quality and brightness, despite only using 200 watts from the wall. Excellent black levels and fairly minimal image retention too. It's a prime example of Panasonic's 2011-2013 NeoPDP tech which is very good.

I just googled the reviews. It seems the 42 inch is not the same as the 50 inch.

Take a look:

https://www.cnet.com/au/products/pan...42u30a/review/

https://www.cnet.com/au/products/pan...50u30a/review/

I only had experience with the 50 inch. That could be the reason we're having mixed reviews.

[syaoran123]

Re: Panasonic TX-P42U30B strange behaviour and now dead

And that review on the 50 inch is in my opinion quite generous. It doesnt deserve a 7.4 rating. Should be lower than that, cos the image quality really is crappy. It's such a shame that this TV exists from a brand like Panasonic. I wouldnt even want to sell it to my customers.

[tom66]

Re: Panasonic TX-P42U30B strange behaviour and now dead

Make sure you turn off CATS, as otherwise the picture is really bad.

The 50" will be dimmer per square metre, due to its larger size and comparatively similar power consumption, but I don't expect the picture quality itself to be much different, if at all.

[syaoran123]

Re: Panasonic TX-P42U30B strange behaviour and now dead

They call it eco mode over here. I always turn it off.

Had another p50u30a to repair and still produces the same washed out images.

I spotted another thread with TW saying the same thing.
https://www.badcaps.net/forum/showpo...7&postcount=12