Panasonic TC-50PU54 8 blinks picture flashes then dead

[aasnowskate]

I have a Panasonic 50 inch plasma TV that has 8 blinks of the red LED Light.
When I plug it in, I can hear the click of a relay. When the power button is pressed, the screen comes on for a second, then shuts down and then the LED blinks 8 times. I unplugged the SS board and then there is a solid light, no blinks but no picture at all. So I replaced the SS board and there is still the same problem.
I am leaning toward the SC board being the problem. When I unplug everything from it, there is still 8 blinks when the TV is turned on.
Does anyone have any thoughts?

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

On the SS board, do you see a point marked TP_SOS8?
I believe this is just a 2012 Panasonic? Heh, the newer ones don't seem to last...

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

Possibly helpful SM documentation

[aasnowskate]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

Thanks for the reply. There is no place on that board marked TP_S0S8. this is a 2012 Panasonic. The service manual you posted is for a TV that has some different boards. This TV has only one SS board. I do appreciate it though.

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

The documentation should be broadly useful, though (8 blink diagnosis in particular) -- I'll try and track down some other documents for you.

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

The TC-P50U54 is the Costco variant of the TC-P50U50 which should be similar to the TC-P50UT50 minus the 3D capability.

[aasnowskate]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

The manual has a great flow chart for the 8 blink problem, but when I follow it with this TV, it has me check the 1 and 2 pins on the SS52 through SS57 connectors on the SS board. When I do this, I have continuity where I should. On that flow chart, it leads me to replace the SS2 board. There is not a Ss2 board on this set.

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

Where does it say replace SS2? I only see replace SS? (On UT50 guide. ST50 has SS2.)

[aasnowskate]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

When checking continuity on SS board, following the YES on the flow chart because I had continuity. This is on the second page of the 8 blink flow chart. the SS57 connector on my set is actually on the SS board.
After reading that, I am kind of thinking it might be the A board?

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

Any chance you can easily test pin 5 of "SS33" or "A33" on SS or A board? Check the voltage there as it shuts down. If it goes high (>2V), the SS board is signalling a fault, either SS, panel or A faulty. If it doesn't A is guaranteed to be faulty.

[aasnowskate]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

I don't have anything to get in there to get a good reading. The points on my meter don't seem to get a good contact on that pin. However, I now do see the TPS0S8 you were talking about earlier. Is there something you would like me to check on there. Sorry for not seeing it.

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

Yes, that has the same function as pin 5. Check that voltage as it shuts down. There is no need to apologise...

[aasnowskate]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

Good, it drops to 0 volts after the tv shuts down. I suppose I will be ordering A or main board. Thanks for the help once again Tom66. this is the second or third TV you have helped me fix.

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

Drops to 0V? I should have said "while it runs" too. What do you get while it runs?
Does that mean it is high when the TV powers up? Because that is SS/A/panel.

[aasnowskate]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

When I first tried, it was around 4.9v and then whent into shutdown, started blinking and voltage was 0, the voltage stays there until I unplug it and start over.

[aasnowskate]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

This is the new SS board that is in there right now.

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

OK, that indicates bad SS, A or panel.
A and panel are unlikely as you do have light emission.
Two red capacitors on the SS board. Left of this image.
https://www.badcaps.net/forum/attach...1&d=1376316458

What voltage do you measure across these, while the panel is operating? If it is between 60V and 150V, that is good. On the SC, there are also two similar capacitors. The voltage across these should be largely the same as what you get on the SS. I would also compare with old SS board if you can do so easily.

[aasnowskate]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

The voltages on the two caps on the SS board and the two caps on the SC board are within the range you listed while the TV first starts up. They then drop when it goes into the shutdown mode. I have not put the old SS board back in as it is kind of a pain. I am still kind of leaning toward the A board, how about you?

[tom66]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

One other thing to check is the SC_UHZ on the A20/SC20 connector. It's pin 9, any way to test it? SC_UHZ may cause 6 or 8 blinks.

[aasnowskate]

Re: Panasonic TC-50PU54 8 blinks picture flashes then dead

When I unplug the SC20 connector, I still get 8 blinks. When I measure the SC_UHZ voltage it is zero when the tv first comes on and when the LED is blinking.