Panasonic TC-50PU50 - 8 Blinks - Tried flowchart

[gent00]

Hi all,

I've looked at the flowcharts from other threads here and tried the following.

How it happened:

My TV emitted a loud buzzing and then the picture went out completely. This was soon followed by 8 blinks on the power LED. Waiting a while and powering the TV back on didn't solve anything.

Here's what I did:

I took the back of the TV off and read some other threads on this forum.

1. I removed the SS33 ribbon and powered the TV on. The power LED remained on, but I was unable to see any sort of emitted light from the panel. I turned off the lights in my room completely and observed this.

2. I then reconnected the SS33 ribbon and tried to probe TP_SOS8 with my scope. It seems that as the TV is turning on ,and going into some 8 blink , then reset loop, the TP_SOS8 is driven high (~5V) momentarily. It then settles back down (0-800mV).

Under both of these situations, I was unable to observe any emitted light from the panel. Does that mean the panel is dead? Or does that mean the "SS" board could potentially have issues?

I also tried to verify a short at Q051, which appeared continuous over my multimeter.

I hope someone understands me

Kind regards,
Avi

[tom66]

Re: Panasonic TC-50PU50 - 8 Blinks - Tried flowchart

Loud buzzing could potentially be a cracked plasma panel. Check very carefully around panel edges for marks or cracks.

[gent00]

Re: Panasonic TC-50PU50 - 8 Blinks - Tried flowchart

Tom,

Forgive me for being naive, but can this manifest itself over time or is it some sort of sudden trauma? I had heard the buzzing pretty loud a day before it completely died. Then the next day, it got even louder..and then failed...

I very much appreciate your help.

Thanks,
Avi

[tom66]

Re: Panasonic TC-50PU50 - 8 Blinks - Tried flowchart

No, that would not be a symptom of a cracked panel. Buzzing in that instance would be loss of picture (either partially or completely) followed by not turning on at all. Your buzzing issue sounds like the all too common Panasonic loose screws issue which fries boards (SC and/or SS.)

[gent00]

Re: Panasonic TC-50PU50 - 8 Blinks - Tried flowchart

I've inspected the panel. It looks OK, but of course I'm not entirely sure what I'm looking for.

Is there any way to diagnose the SS and/or SC before trying to obtain those and replacing?

Thanks,
Avi

[gent00]

Re: Panasonic TC-50PU50 - 8 Blinks - Tried flowchart

Did some more research today. Apparently, the panel IS turning on. It's very very brief, but it doesn't look broken or cracked.

I removed the SS board and found some strange arcing marks. I guess this is a known problem because I found a technical bulletin on this forum about replacing the 3 components.

I've ordered a new SS board as well as the discrete components to replace onto the old board and put up for sale (or keep as a spare).

Will update everyone when I have those things.

[tom66]

Re: Panasonic TC-50PU50 - 8 Blinks - Tried flowchart

Yes, I was ruling OUT a cracked panel for now. Especially if you have light from the panel.

[gent00]

Re: Panasonic TC-50PU50 - 8 Blinks - Tried flowchart

I replaced the SS board last night and the TV is working again. Thank you Tom!

Thanks,
Avi