Panasonic TC-P55ST30 Interpreting SU-SD tests

[FastEddie52]

I have a 2011 P55ST30 with a sold led power led that switches to 14 blinks when the power button is pushed again. I have checked all the power lines, Vsus, Vda and P15 and find no shorts. SC2 is Ok. I was testing SU and SD boards and I get the following resistance readings. On SU42-2 VFO I get 2.2 m. On SD42-6 5V_F I get 1.6m and on SD42-8 SCNR_PRO I get 1.6m. All other pins were open. Black probe was on floating ground screw.

I saw a chart posted that had readings at some of the other pin locations. What does the lack of resistance indicate if anything?

[tvtimmy]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

Low resistance means short. I use the continuity , or beep function, on my meter.

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

Sorry I meant it had an infinite or out of range resistance. This is on Rx2000 range

[budwich]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

have you checked your batteries in your meter? weak or poor batteries will cause issues. Further, you post readings BUT you also need to post what you think / read the readings should be so that people don't have to go looking all over to figure out what you are saying.

"no / high" (higher the normal) resistance could a component that is burnt / blown... again depending on what it was suppose to be OR that you have a poor connection point for your test reference.

in addition, you need to check all your readings of "ground" against a known ground. You indicate that you are using the "float ground screw" as the reference... but that point may be compromised as not totally grounded (because of poor contact... which might have taken out the board to start with). All the ground points should read 0 ohms with respects to one another (taking into account any lead resistance).

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

I tested the grounds and they all read 0 resistance from board to board and to chassis. So I found a chart of resistance readings for SU42 and SD42.

SU42 Guide Mine

Pin 2 VFO 1.3m 2.026m
Pin 4 VSC-F 217K NR
Pin 8 5V-F 2.3m NR

SD 42

Pin 1 VFO 1.1m NR
Pin 2 VSCN-F 218K NR
Pin 5 5V-F 500K NR
Pin 6 5V-F 500K 1.6m
Pin 8 SCNR-Pro 1.5m 1.6m

The NR is either infinity or out of range on a 2000K range

[tvtimmy]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

If your meter beeps when probes are touched together, place one on a floating ground.
Then take the other and rake across the ribbon connecters. If you hear a beep you have a shorted ic on your buffer board.

[tom66]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

If your meter beeps when probes are touched together, place one on a floating ground.
Then take the other and rake across the ribbon connecters. If you hear a beep you have a shorted ic on your buffer board.

This is all you need to do.

Tests of resistance in the "M Ohm" range tell you very little & are hard to interpret.

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

So nothing is shorted, so I can assume that those boards are good. I cannot find a short anywhere in the TV, but it still gives the solid Power Led light as the error. This error is supposed to be either shorted Vsus, Vda, or P15v. All of those are not shorted, so I don't know where to turn at this point.

[tom66]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

Can you check what your VSUS voltage is when the TV turns on?
Then repeat the test with SC and SS disconnected.
Important to do this to verify if there's a short that appears only when the board is energised, that might not otherwise appear.

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

With all the boards connected, Vsus is 197v Vda is 55v and P15 is 15v until SOS shutdown kicks in and the voltages drop. With SC2 disconnected, the voltage at P2 is 197 then goes to 204 and then drops once shutdown occurs. When SS board is disconnected the same voltages occur and also with SC and SS disconnected.

[tom66]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

SOS in this case with 14 blinks would make me consider the main board as bad.
If there is an LED on the SC/SS boards, does it light up briefly?

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

No green lights on boards. I bought a used main board, but nothing changed. Seller swears it was working.

[budwich]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

can you clarify your resistance test of the sc2 connection on the su board (sorry I am not at my usual internet connection). that measurement is NOT done to the ground.

further, there are threads with a "troubleshooting guide" for plasma 2011. I think one of the tests once you get the 14 blinks, is to then unplug the power to the su board and power up again and what, if any code you get and go from there.

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

When I checked before SC2 was high over 1 meg. I have the guide and and followed all the decision tree flowcharts and have found nothing. On the one for the solid power light it led to a bad main A board, but that was replaced with no difference.

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

I tried pressing the power switch immediately after plugging in the tv just as the relay clicked. The power led remains on with no blinking.

[tom66]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

If the TV has an optical port, does that light up briefly?

It is quite possible the new main board you got is defective.

Was it for exactly the same set?

Does it have any missing or extra connectors - we have seen one where Panasonic built some of their plasmas with fans but then changed the design and dropped the fans mid-year. As such boards designed for fans but having none connected trip a fan fault error.

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

The optical audio port light does come on briefly until the TV enters shutdown. The board numbers are identical including suffix. According to the seller of the board, the board came out of a TC-50ST30 where the screen was cracked, but it was working before the boards were stripped. The A board is a TNPN09121AD. This is same number that shopjimmy sells for the TC-P55ST30.

[tvtimmy]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

??????????????????????????????????????????????????????????????????????????????
Where did you get that part number from?

[FastEddie52]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

Sorry it is TNPH0912(1)AD. Attached is a picture of the number from the board.

[tvtimmy]

Re: Panasonic TC-P55ST30 Interpreting SU-SD tests

You have to use the exact mainboard that came out of your set. I know this because I had a panny that had 2 sets of parts, a board,sc board,and d board. Ss and su/sd boards are interchangeable. I had to buy the A,D, and SC to fix it.