Panasonic TC-P50G20 clicking, no blinking led

[EC911]

Hello,

I have a plasma tv that I'm trying to repair for a friend, the tv was working fine this morning when I turned it on for the first time, after 30 mins playing a movie it turned off, making a clicking relay sound coming from the P board.

There's no blinking light and the TV didn't want to turn back on even after letting it sit for a couple hours unplugged.

I opened it and I don't see any blown caps, no burnt spot, fuses seem fine on the P board. I tried unplugging SS and SC one at a time but no luck, only a clicking noise is heard.

Apprently the power supply has been replaced already on this TV, could it be a blown main board?

Thanks

[tw2005]

Re: Panasonic TC-P50G20 clicking, no blinking led

Power supply faults would be rare on these, I have not read any yet so maybe the PSU was replaced dude to an intermittent shut down which has now become permanent.

the common fault with these is a shorted SC which shorts the Vsus on the PSU but from what you say it's sounding like A board.

You would have to confirm what standby voltages are present, there is a good fault finding guide for this series.

No LED or blinks does sound like an A board issue, with the SC faults commonly 4 or 10 blink.

Try disconnecting, SC20, SC2, SS11, P35, 3 white ribbons at the A board. If you still have clicking, no LED or blinks etc, A board would be prime suspect. After you try that(on , no more than 30 secs) DO NOT reconnect any of those power cables for a good 5 mins or so as residual volatge may be there and spike a board or damage the panel!

I'll find the link for the guide and edit this post.

https://www.badcaps.net/forum/attach...6&d=1394006853

[EC911]

Re: Panasonic TC-P50G20 clicking, no blinking led

After doing some tests following the guide, I found that the A board is likely at fault. Is there any test I should on that board to find the broken component it before ordering a whole board?

[EC911]

Re: Panasonic TC-P50G20 clicking, no blinking led

Ok just a quick update, while reassembling the board and trying it again, the TV actually turned on, but while the screen was on, I could see alot of horizontal flickering white lines, like noise, on the screen. I also heard a faint spark noise on the bottom of the screen so I unplugged right way... The power led did also turned on, no blinks.

Could it be a short somewhere or a partial short even if I tested Vsus Vda and P15V and they all seem good?

[tw2005]

Re: Panasonic TC-P50G20 clicking, no blinking led

After doing some tests following the guide, I found that the A board is likely at fault. Is there any test I should on that board to find the broken component it before ordering a whole board?

Too hard really

[tw2005]

Re: Panasonic TC-P50G20 clicking, no blinking led

Ok just a quick update, while reassembling the board and trying it again, the TV actually turned on, but while the screen was on, I could see alot of horizontal flickering white lines, like noise, on the screen. I also heard a faint spark noise on the bottom of the screen so I unplugged right way... The power led did also turned on, no blinks.

Could it be a short somewhere or a partial short even if I tested Vsus Vda and P15V and they all seem good?

Almost suggests the A board was ok if all the voltages came up.

Sounds weird, impossible for me to say. maybe some good clear photos of everything. maybe a cable has been pinched or maybe there is an issue with the SC board or buffers. Did you try my suggested test with just the A board and psu connected, everything else disconnected?What was the result?

Was the noise on the same side as the SC board?

[EC911]

Re: Panasonic TC-P50G20 clicking, no blinking led

I did the test you suggested, with all the cables disconnected the TV turns on no problem with a solid power LED. I reconnected everything after that and I turned it on again and recorded a video of the lines I'm talking about. There's alson a black bar on top of the screen that doesn't seem right.

https://www.youtube.com/watch?v=XjwTvQckBkk

The noise that I was hearing was coming from around C1,C2 or K board..

[tom66]

Re: Panasonic TC-P50G20 clicking, no blinking led

Top bar could be Y-buffer cable not seated.
Looks a lot like A board, perhaps can be confirmed via test patterns?

[tw2005]

Re: Panasonic TC-P50G20 clicking, no blinking led

I'm not real sure with that fault, test patterns may be handy place to start. It's interesting you've gone from totally dead to it turning on again.

[EC911]

Re: Panasonic TC-P50G20 clicking, no blinking led

I've reseated every cables and ribbons on the buffer board, SS, C1 and C2 and I've tightened all the screws. now the TV turns on with no more white lines, no spark sound and the black is almost all gone except a thin black line that goes accross the screen on the top portion of the panel.

I'm also having now some green fuzz on the top portion also that wasn't there before...

https://www.dropbox.com/s/7nlgx9zxfu...35604.jpg?dl=0

[jjanssen7]

Re: Panasonic TC-P50G20 clicking, no blinking led

That looks like something going on with the upper buffer board to me.

[tw2005]

Re: Panasonic TC-P50G20 clicking, no blinking led

That looks bad top and bottom. I've never tried this on a panasonic, but it may be able to be run with one buffer. If i was to try that, I'd try isolating the top board. SU. I don't know if anything bad can happen, it does suggest it in the training guides.

I see lines equidistant from top to bottom which has me curious. In the training guide link I posted for you, page 40 pay close attention to what must be disconnected and what does not. If the bottom comes up perfect then I would say bad SU. Also there are some resistance tests for the SC, SD,SU boards, may be worthwhile to follow those steps and post up just in case there is an indication.

[tw2005]

Re: Panasonic TC-P50G20 clicking, no blinking led

have you made a close inspection of the SC board for anything burnt or unusual. Maybe get a hi res image of it.

[EC911]

Re: Panasonic TC-P50G20 clicking, no blinking led

Ok I isolated SU and SD together according to the guide, page 39 and the TV doesn't turn on at all. I get 7 blinks.

I also measured the resistance on SU and SD to test for shorts according to page 43 and both boards seem ok.

Following the 7 blinks troubleshooting guide, it seems that SC might be the problem. When I disconnect SC20 and I get 6 blinks which according to the guide, it says to replace SC. I even tried to isolate SU and SD seperatly and the tv doesn't turn on either.

I'll remove the SC board again and take a good look at it, I'll try to get a good picture of it to post it here.

[H20ENG]

Re: Panasonic TC-P50G20 clicking, no blinking led

Hello,
This is the only thread I can find anywhere on the web with the same symptoms I am experiencing: Relays continually clicking, no LED at all, same TV: TC-P50G20.
I metered the fuses on the power supply board. I get 120VAC on the 2 lower right fuses, no power on either side of the fuse on the lower left fuse, and fluctuating 55-62VAC depending on relay state on the upper fuse.

I am not sure I can perform the other tests mentioned without the power supply working correctly. My fear is buying a new power supply board only to find something else is shorting it.

Anyone else have this clicking, No blink issue?
This is a great site so far! Thanks for being here!

[tw2005]

Re: Panasonic TC-P50G20 clicking, no blinking led

somewhat confusing without actual fuse location numbers.

F602 is neutral line
F601 is active line
F501 is on the active line for the 5V STDBY cct.

F201 is on the PFC cct

Try disconnecting Sc2,SS11, P35, 3 white ribbons and turning it on. Don't reconnect sc2,ss11,p35 for 5-10mins after it's turned off as residual voltage will be there and can damage boards and panel if it spikes.

See if it still clickety clicks

[H20ENG]

Re: Panasonic TC-P50G20 clicking, no blinking led

Thank you tw2005 for the quick reply. I was out of town for the weekend but will try this tonight. I will also correlate the correct fuse numbers to my post above.

Oh, I also noticed the optical audio connection lights up red when the relays change state. Its the only light I can see on the whole unit. More later. Thanks again.

[H20ENG]

Re: Panasonic TC-P50G20 clicking, no blinking led

Still clicking with the connectors removed. Removed P6 and P7 and it no longer clicks. Reconnected all but left P6&7 disconnected. No clicking. Seems like A board?

[H20ENG]

Re: Panasonic TC-P50G20 clicking, no blinking led

P7 is the one that makes it click. Looks like these boards are getting scarce. Does anyone repair them at component level? Yikes.

[tw2005]

Re: Panasonic TC-P50G20 clicking, no blinking led

P7 is the one that makes it click. Looks like these boards are getting scarce. Does anyone repair them at component level? Yikes.

been scarce for quite a while, don't know of any cheap option either way it's pricey.

http://www.ptselectronicsinc.com/txn-a1mguus/