Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

[tom66]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

The missing lines won't come back, and the panel is damaged and shorted in that area which will kill the new SN board within short order. If the crack was somehow only on the outer surface it might be ok but since there are missing lines the panel itself has been compromised. It might not have leaked gas (somehow...), but it has shorted.

I have seen this before. Some cracked plasmas will operate for some time, especially the more modern ones. The buffers always die though, usually taking the picture with them. In some rare cases the buffer ICs fail open circuit and just that part of the picture dies.

The instantaneous short idea is interesting, but I have heard of boards from shipping damaged TVs which are bad, after customers power the TV on for the first time with the crack. I think the short just kills the boards in many cases. Not always, but often.

[Chaks]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

Yesterday morning I carried my tv to the service centre. It was late afternoon they called me to come as they estimated the repairs.They told me that the panel is working for the moment but cannot guarantee how long as the crack may become larger over time ( ... short time ) and will eventually fail. The SN board was faulty - gone bad from the shock of the impact and it has to be replaced.

The estimate was $150 for the SN board, $30 for labour, and if I want to replace the panel it would be cost me $500. Total repair would cost me $680 with new panel and without any warranty on it ( they said 30 days it's as good as nothing).

At a minimum I have to buy the SN board to take back a working but a broken tv.

They did show me the tv with a working SN board to support their estimate. They were a total of 12 missing lines (5 vertical and 7 horizontal). They sealed the cracked area with a transparent glass-like adhesive sheet.

Do I need to pay $180 for the SN board ? ... To be installed in a broken tv.

I finally paid $25 as estimation charges and brought back the tv.

The service guy was kind enough to explain me why the panel could survive the crack. He told me that there is a vacuum seal just like a flask on the top-right corner of the panel (back side). It is very fragile and can easily break open due to shock from impact. Crack on my tv was on the bottom-left of the screen (facing the panel) and thus the panel was still alive. The shock may not have travelled anywhere near the most venerable point. The momentary fluctuation of scan pattern on impact will kill the driver IC's on the SN board. A senior technician in late forties says he has seen many plasma TV's destroyed that way. A small punch to the left-top corner of the panel (facing the panel) is enough to destroy the pana tv.

So this is the end of the story for my tv. I will keep the tv just for academic interest.

I don't have enough courage right now to buy a new big tv again.

Thanks everybody ... Bye

[Chaks]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

Thanks a lot for your replies tw2005 and others on this forum.

The components on the SN are too small to test and even more difficult without a full schematics of the pcb. I had been on this for a week now and it's time to decide either way ...

1. Dump the whole thing and buy a new led tv. OR
2. Take the tv to panasonic service centre and get it estimated and then decide.

I will update when I get a feedback from panasonic service centre.

[tw2005]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

I think the chances are the SN could be damaged. I know whenever I've purchased boards from a smashed TV that was operating at least on buffer usually sd is shorted, since this is combined it makes it difficult to check. I think you'll have to base your decision based on the expectation other boards may need replacing.

I'm out of ideas.

[Chaks]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

The SN board block diagram:
https://drive.google.com/file/d/0Bxc...ew?usp=sharing

[Chaks]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

Tw2005 I forgot to remove the ss55a and ss53 panel connectors on the ss board (power + ss board) when I tested earlier ( it was a mistake) .

I did the test again now .... The panel does not lit up when both ( SN -> panel ribbon cable and SS -> panel ribbon ) were removed. The led blinks 7 times and shuts off. The transition from blinking white power led to flashing red 7 times was noticeably faster. It's quick.

I did one more test by removing the p35 connector along with both the ss and SN panel connectors ... It's the same result .... Panel does not lit up and very quick transition of power led from flashing
white to 7 red blinks.

[tom66]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

It is surprising the panel lit up - cracks usually lead to loss of gas, which is terminal to the panel. It won't light up, even if you shove 2000V across it!

[tw2005]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

SRV VFO to all the pins of panel connectors are open. I checked this thrice to be sure.


Tw2005: "I was thinking , disconnect the panel ribbons from both the SS and the SN, but have the SN connected as normal, fire it up and see if it stays on."

When I did this ... The panel lits up for 2 seconds ... No hiss sound from the speakers ... The power led blinks 7 times again. Back to the beginning.

When I disconnect the SN board ... The panel lits up white for 5 seconds along with hiss sound from the speakers ... And blinks 6 times ( six times ). I have also noticed that a Red LED below the optical-audio-out board connector on the 'A' Board lit up for about 5 seconds. The red led lit up as long as the white screen was displayed. This I did not notice when I did the testing earlier.

It seems that the SN board is faulty. The SN board costs about $ 100 here in India. If the SN board is repaired then it is ok ... otherwise it becomes a $275 panel + $100 SN board = $ 375 ... For the parts alone.

actually just realised C buffers are still powered, maybe P35 needs disconecting to remove power because the panel should not light up.

[Chaks]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

SRV VFO to all the pins of panel connectors are open. I checked this thrice to be sure.


Tw2005: "I was thinking , disconnect the panel ribbons from both the SS and the SN, but have the SN connected as normal, fire it up and see if it stays on."

When I did this ... The panel lits up for 2 seconds ... No hiss sound from the speakers ... The power led blinks 7 times again. Back to the beginning.

When I disconnect the SN board ... The panel lits up white for 5 seconds along with hiss sound from the speakers ... And blinks 6 times ( six times ). I have also noticed that a Red LED below the optical-audio-out board connector on the 'A' Board lit up for about 5 seconds. The red led lit up as long as the white screen was displayed. This I did not notice when I did the testing earlier.

It seems that the SN board is faulty. The SN board costs about $ 100 here in India. If the SN board is repaired then it is ok ... otherwise it becomes a $275 panel + $100 SN board = $ 375 ... For the parts alone.

[Alastair E]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

Nah--If the PANEL IS CRACKED in ANY way, shape or form, Its Finished! Curtains, Shuffled off this mortal-coil, Gone to meet its maker, Its an Ex Parrot OOps, Plasma
This TV is deceased.

Time to change your preferred sport--Maybe to jogging. No danger to TV screens from that!

It is Highly unlikely you'll find any shorts on its electrodes, its a case of arc under a high-voltages the panel runs at normally will then kill other items on the SUS boards/Buffers.

[Chaks]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

Specs of TH-P42XT50 from panasonic website.

http://www.panasonic.com/sg/consumer...t50.specs.html

Online retailers selling the same model here in India
http://m.snapdeal.com/product/panaso...t50d-hd/609340

http://www.gadgetsguru.in/panasonic-...dia-15945.aspx

I never bothered too much with the specifications at the time of purchase but I think I may be lucky this time to have bought a viera tough panel tv unknowingly. A bit more hope that the panel may be alive somehow.

[tom66]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

These newer panels don't have the Tough Panel, the glass is very easy to damage (though not as easy as an LCD.)

[Chaks]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

Now I realise ... The golf ball came from behind and hit the tv. Had it hit me on the head I would have been in the emergency care ( a more expensive case).

The guy in the video says the panel can withstand 4 joules ( I don't know how to relate that figure to impact ). I think it was one of the best timing shot from my kid with a short club and it may also be that the running panel was hot enough to lose its claimed toughness to impact force. The golf ball because of its smaller dimension may have Exerted more force at the smaller point of impact. Never new that golf ball was so hard.

I will test if there is anything short in the panel ribbon cables and report back.

[tw2005]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

I was looking at this. https://www.youtube.com/watch?v=aXEu04k_YMM

Your kid must have a good arm to have cracked it then. Must have been a big hit.

[tw2005]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

Pin 1 to 2 and pin 2 to 3 is 295 ohms. Pin 1 to 3 is dead short on Daf30a.
I have not yet removed the panel from the cabinet/bezel. But when I look at the panel edges it seems like there is no separate glass between panel and the bezel. The TV specs mention the panel as VIERA Tough Panel .. I don't know what it means.
Tw2005, I will test as you mentioned. Is there any test I can do on the panel to specifically know if it has shorted electrodes.

I have not idea what the correct resistance is on that diode, and no I doubt you can check the panel like that. tough panel, well be interesting to know if it can crack and preserve the panel. the fact you still see a flash of white has me curious.

7 blink shutdown is going to be either Sn or panel or both. have never been in this situation

[Chaks]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

Pin 1 to 2 and pin 2 to 3 is 295 ohms. Pin 1 to 3 is dead short on Daf30a.
I have not yet removed the panel from the cabinet/bezel. But when I look at the panel edges it seems like there is no separate glass between panel and the bezel. The TV specs mention the panel as VIERA Tough Panel .. I don't know what it means.
Tw2005, I will test as you mentioned. Is there any test I can do on the panel to specifically know if it has shorted electrodes.

[tw2005]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

In your first line, you say--

Slightly cracked Panel ( 2 inch 'X' shaped crack on the left bottom side) got hit with a golf ball...........

Can you confirm, that its just the front protection-glass and NOT the actual Plasma Panel thats cracked...?

IF the Plasma Panel has suffered a crack/damage, then this will be causing your problem.

SOS-7 is related to floating-supplies and Buffer circuits as I recall....

I had a look in the US model XT50 and it did not show a front protection panel in the PDP removal procedure. Do you know if these have one? I know Panasonic started deleting these in the higher end panels from about 2010.

[Alastair E]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

In your first line, you say--

Slightly cracked Panel ( 2 inch 'X' shaped crack on the left bottom side) got hit with a golf ball...........

Can you confirm, that its just the front protection-glass and NOT the actual Plasma Panel thats cracked...?

IF the Plasma Panel has suffered a crack/damage, then this will be causing your problem.

SOS-7 is related to floating-supplies and Buffer circuits as I recall....

[tw2005]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

DAF30 sounds like a diode? are you saying pin 1 & 3 short if you test between the 2? = normal, common cathode, anode - anode = short cct

[tw2005]

Re: Panasonic Plasma TV TH-P42XT50D PCB - 7 blinks

I was thinking , disconnect the panel ribbons from both the SS and the SN, but have the SN connected as normal, fire it up and see if it stays on.

What I don't know is if doing this can pop a board. I've done this once on a LG plasma with no damage to the boards(had cracked screen) to prove them.

The newer manuals are too hard to blow up as they lose resolution and I,m not 100% sure. All i can suggets is the first option at your risk or check resistance across SN2 and then find the Test point SRV VFO on the SN , place one lead there and then slide the other slowly across the face of each pin connector at the SN panel ribbon connectors and see if there is a dead short on ay of those, use diode mode or whatever beeps.

that's the best I can do having not seen or tested a SN before like this.