Panasonic p50g20 power board failure?

[Tinkerless]

Hi,

2 days ago my p50g20 failed and powered off, don't think any visible error blink codes were shown.

This tv has always produced a buzz when displaying very bright images mostly noticeable at night time, the brighter the image the louder the buzz. This has been getting worse until the other night when during an almost full white screen there was some crackling/arcing noises and the set powered off by itself. Checked for smoke/smell and couldn't find anything switched back on to test and all seemed ok again until another white screen and more crackling/arcing and switched off again. Switched the unit off at the side power button and started to scratch my head when the arcing/crackling noises started again and I paniced and just pulled the power cord.

I have opened up the back to have a look to see if anything obvious, there is a capacitor on the power board that is slightly bubbled but otherwise no other visible symptoms.

So what next? Can I test the power board in isolation without any other connections? Is this safe? I'm comfortable replacing the power board with a like for like replacement but not confident soldering components. The unit has a lot of dust inside, could the also be a factor?

Could there be other non visible damage to other boards?

Before the failure the unit had no other problems, great picture and colours etc.

Any advice greatly appreciated.

[sordids999]

Re: Panasonic p50g20 power board failure?

Pictures of the back of the tv showing all the boards
May help you more

[Alastair E]

Re: Panasonic p50g20 power board failure?

P-50G20, Thats the cut-down Cheapo Argos special, innit??

Tighten ALL the board mounting-screws, especially those os SC and SS boards.

Probable usual arc fault that kills the SC board etc--and You DONT want to go There!!

[Tinkerless]

Re: Panasonic p50g20 power board failure?

Here are some shots of the insides including a close up of the bulging capacitor (wasn't argos, was from currys I think) :

https://www.dropbox.com/s/m78penb1bx...81303.jpg?dl=0
https://www.dropbox.com/s/n6ru08lz3o...90147.jpg?dl=0
https://www.dropbox.com/s/ghdylqj4bd...90213.jpg?dl=0
https://www.dropbox.com/s/ijzlskde60...90226.jpg?dl=0
https://www.dropbox.com/s/ijzlskde60...90226.jpg?dl=0
https://www.dropbox.com/s/ubdcokekrw...90232.jpg?dl=0

[Moreno83]

Re: Panasonic p50g20 power board failure?

Try to upload the pictures in advanced mode. ( Attachment option ).

[Alastair E]

Re: Panasonic p50g20 power board failure?

As I said--Tighten ALL the screws on ALL the boards.

Cut-Down sets are sold by the chains such as Argos. Thats why they are cheaper--Because they are MADE cheaper than the premium set.

The premium model we'll say uses 4 transistors in parallel, Cut-down set will use say only 2 maybe 3--As little as they can get away with--All user apparent features are the same, so buyer has NO idea, only the Model Number indicates the difference.

Thats why they are cheap. Buyer THINKS he's getting a deal--But he isn't as the reliability is compromised by the use of less parts (And CHEAP SCREWS!)

This issue is particularly apparent with Panasonic sets....

[vinceroger69]

Re: Panasonic p50g20 power board failure?

maybe in a very dark room power the set up with the back removed you maybe able to see where its arcing etc !!but dont do this long at all as dont want a blown sc board etc!!

[Tinkerless]

Re: Panasonic p50g20 power board failure?

The set is a Panasonic Viera TX-P50G20B and I have had this for approx. 5 years. I'm happy to try tightening the screws but as the set hasn't moved in the last 4yrs I'd be surprised if loose screws would be the cause?

I thought this was a mid range set not a budget argos tv.

[Tinkerless]

Re: Panasonic p50g20 power board failure?

maybe in a very dark room power the set up with the back removed you maybe able to see where its arcing etc !!but dont do this long at all as dont want a blown sc board etc!!

Would it be possible to test the power board without anything else connected to it? Remove all the other connectors and ribbons?

[vinceroger69]

Re: Panasonic p50g20 power board failure?

the screws have been re designed with a extra washer etc as this is a known fault now you can get updated screw kits etc.

[vinceroger69]

Re: Panasonic p50g20 power board failure?

Would it be possible to test the power board without anything else connected to it? Remove all the other connectors and ribbons?

i would guess so but im not sure which pins on the psu you would have to link with resistors etc maybe a more experienced member will advise whats the power supply board number?.

[Alastair E]

Re: Panasonic p50g20 power board failure?

The cheapo screws work loose By Themselves!

The arcing to chassis is what destroys the SC. Do Not run it agan till you've tightened 'em, or you risk blowing the SC etc--And That'll cost lots!

[vinceroger69]

Re: Panasonic p50g20 power board failure?

as alastair e suggested a few posts back defently tighten those screws up first it may not solve the problem but may stop other boards from shorting out and if possible upload some pictures of the power supply and the bad capacitor you can see your self.

[tw2005]

Re: Panasonic p50g20 power board failure?

This model does not suffer from loose screws AFAIK. has the good old bolts before they stuffed up in 2011.

So is this TV working or not now?

[tw2005]

Re: Panasonic p50g20 power board failure?

Just had a look at the SS image, I would blow out and clean all that dusty crud off all the boards especially the SC,SS,P .

That in itself could be arcing, I have worked on a 2009 G10 and literally had a board arcing across from a heatsink to a nearby component all due to build up, scared the crap out of me at the time.

[Tinkerless]

Re: Panasonic p50g20 power board failure?

This model does not suffer from loose screws AFAIK. has the good old bolts before they stuffed up in 2011.

So is this TV working or not now?

No haven't tried putting power back into it again. Just tried to upload picture of the bulging capacitor, it's the 230v one in the background :
https://www.dropbox.com/s/n6ru08lz3o...90147.jpg?dl=0

[tw2005]

Re: Panasonic p50g20 power board failure?

If you remove sc2,ss11,p35, 3 white ribbons at the A board it should power up normally but do no more than 30secs or it will fail and shutdown with a 4 blink code with no load.

Don't reconnect those until the voltages have dropped off those leads especially P35 or you can damage the panel

[vinceroger69]

Re: Panasonic p50g20 power board failure?

tw2005 so basically the loose screw arcing issue is sets made after 2011? does this apply to all the panasonic range of plasmas, because ive saw you mention the loose screws in various threads i didnt realise it was after a certain year so good imformation to know.

[tw2005]

Re: Panasonic p50g20 power board failure?

No haven't tried putting power back into it again. Just tried to upload picture of the bulging capacitor, it's the 230v one in the background :
https://www.dropbox.com/s/n6ru08lz3o...90147.jpg?dl=0

It's quite common for those large HV caps to have a natural dome to them and bad caps are fairly rare in these. Most issues are SC or A board in these.

I reckon pop the sc , ss ,, p out, inspect and clean, even a soft brush. I've seen roaches get trapped under boards and burn to a crisp in a LG, blew a buffer in that. I'm assuming this is working but the SC can buzz and if loose as the other guys mention can make a very loud noise but it's more of a buzz, not crackling noise when I've heard it leaving screws out.

[tw2005]

Re: Panasonic p50g20 power board failure?

tw2005 so basically the loose screw arcing issue is sets made after 2011? does this apply to all the panasonic range of plasmas, because ive saw you mention the loose screws in various threads i didnt realise it was after a certain year so good imformation to know.

From everything I've read and seen here 2011 on , not sure after 2012 only seen 2011 and 12 models.

I own one of the P50V20A , still a good TV