Panasonic TC-P55ST30 Interpreting SU-SD tests

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

I thought that might be a problem but since they had the same suffix, I thought it would work. The P50ST30 has a AC version of the board according to various sources. The P55ST30 does use the AD version. How the AD got in the P50 is a mystery to me. How does the manufacturer keep these straight if they are not interchangeable between models?

[tom66]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

The 50" and 55" panels are different. The A board controls the plasma discharge; with the wrong board, problems could happen, such as maldischarge (misfiring pixels) or SC/SS failure. I can't be sure if your 14 blink symptom is caused by it, though.

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

This is actually the "Solid Red LED Failure (Locked Mode) that was was implemented for the 2011 model. Attached is the troubleshooting flowchart. So you disconnect SC2, SS11, and SC20. Is the led blinking? Yes then is it blinking any other number times beside 6? Yes (8). Then Replace A boardand check Vsus and P15v for short circuit. (The flowchart is attached) This is what led me to replace the A board in the first place. I am going to get another one since nothing else shows up as a fault.

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

I bought a new main board for the TV and installed today. Nothing has changed, so I am at a loss for what is wrong

[budwich]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

Based on my limited experience with a 50s30, how about trying just an sc2 disconnect with everything else connected.... what is the result? I guess the question is... are you counting your "toes" correctly? :-)

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

With SC2 disconnected, I get 7 blink error

[budwich]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

OK... the other guidance that I got was then to check each of the fets and diodes on the board using the black lead on the large contact ("top") and measuring resistance at each of the other legs? do this for all and compare your results? Anything stand out?

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

are you talking about the heat sink or the middle leg? Use diode or ohms setting?

[tom66]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

With the surface-mounted transistors

https://www.google.co.uk/search?q=to-263&tbm=isch

(TO-263 type)

and the smaller "DPAK" type, the tab pin is connected to the middle pin, so you can use either.

[pascalo]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

For check the su and sd board there is a video for if you are more visual

https://www.youtube.com/watch?v=-JVLWpcIxJQ&t=16s

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

Update on my TV. I sent the SC Board out to be repaired, but the repair shop could not find the problem. So I bought a used SC board and that fixed the TV. I bought 2 A (main) boards thinking that was the issue. I guess I will resell them on ebay. Thanks for for all your help.

[boydsc]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

Does anyone happen to know what kind of resistance reading I should have across the SC2 plug on the SU board ?

[Moreno83]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

Put your meter in continuity mode.

Black prope on ground ( screw hole ) and slide the red prope against the ribbon connectors...beep is bad. Best way to test.

[boydsc]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

ok when done that way I get 4 to 5 beeps along the ribbon connector. I was told that measuring across the SC2 connector which is the power connector for that board I should not get a beep or there is a dead short somewhere on that board. which I did get a beep. I removed Q401 and Q402 from the board and the short went away. I think those are transistors. Could these be my only problem on this board ? I've never heard the ribbon check tho.

[Moreno83]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

It is best to start your own thread with pictures of the boards. There must be more short on the board beside those 2.

https://www.youtube.com/watch?v=51SZsfH60EY