Panasonic TH-50PZ77U 7 blink code (SOS7)

[Computer_Eng]

I'm getting a 7 blink code (SOS7) on my Panasonic TH-50PZ77U 50" Plasma (set is likely similar to the 42" TH-42PZ77U). The SOS7 code generally indicates a problem with the Y sustain circuit (i.e., the SC, SU and/or SD cards).

Here are the current symptoms.

If I run the set with the SC (Y sustain) and the SU (upper buffer) plugged in and the SD (lower buffer) unplugged, the set works with a picture on the top half of the screen.

If I plug in the SU and the SD cards without connecting the ribbon cables from the SD to the plasma panel, again the set works with half a picture.

If I plug one or more of the 5 ribbon cables between the SD and the panel, the set shuts down after a second or so with an SOS7 code.

When I power on with the SD card plugged in and cabled to the panel, sometimes the set tries to put up a picture (you can briefly see an off color image), but then the set goes to SOS7.

I tried two different SD cards and the set worked for about a week and then failed with the same symptoms. I don't see any obvious shorts on the SC/SD/SU cards.

When the SOS7 is triggered, the set goes into standby mode and more or less shuts down, so it's difficult to determine the underlying cause of the shutdown.

Does anyone have a suggestion on what might be causing the problem or what I could do to isolate the failed components? Could the problem be in another part of the set?

[Moreno83]

Re: Panasonic TH-50PZ77U 7 blink code (SOS7)

Ribbon cables are connected correctly? Did you try ( if you have spares) a different ribbon cable?

[Computer_Eng]

Re: Panasonic TH-50PZ77U 7 blink code (SOS7)

Ribbon cables are connected correctly? Did you try ( if you have spares) a different ribbon cable?

The ribbon cables I'm referring to are the ones connected to the plasma panel. Those cables are permanently connected to the panel so there's no possibility of swapping them out. The only other cable connection is between the SC and the SU card and that cable is attached (soldered) on the SC side.

[tom66]

Re: Panasonic TH-50PZ77U 7 blink code (SOS7)

So you are saying it doesn't matter WHICH cable you put in... but any one in the SD board and it shuts off?
Did you try all single-ribbon combinations?

[Alastair E]

Re: Panasonic TH-50PZ77U 7 blink code (SOS7)

Sounds like to me an intermittent plasma-panel short/fault killing the buffer-boards.....

Look over the affected area VERY closely, Any black spots on the panel or damage to any of the screen-tabs indicates issues. You may have to de-case the panel to check properly.

[tom66]

Re: Panasonic TH-50PZ77U 7 blink code (SOS7)

Sounds like to me an intermittent plasma-panel short/fault killing the buffer-boards.....

Look over the affected area VERY closely, Any black spots on the panel or damage to any of the screen-tabs indicates issues. You may have to de-case the panel to check properly.

I'd agree - but only if it affected only one ribbon... Sounds like it's ANY one ribbon and it'll shut down. Chances of five ribbons all having the same failure are slim IMHO...

[Computer_Eng]

Re: Panasonic TH-50PZ77U 7 blink code (SOS7)

I'd agree - but only if it affected only one ribbon... Sounds like it's ANY one ribbon and it'll shut down. Chances of five ribbons all having the same failure are slim IMHO...

Yes, any one ribbon seemed to be shutting it down, at least that was the way it was working yesterday. This morning, I powered up the set and went to double check this. I connected one ribbon cable after another after another, checking the set after each ribbon cable was in place. After all five cables were in place, the set was still running perfectly and has been working fine for the last several hours.

I guess I'll just enjoy watching the set until it decides to fail again. Last time it worked for a week before it died.