Panasonic tc-p58s2 SC, SU or SD Board issues

[engelwood39]

First off I am a newbie to this and am trying to save a TV that I cannot seem to find an SC Board for(which I think may be the problem). If this is something that I can be guided through to find the problem I am fairly proficient with desoldering/soldering. I just am not sure what and how I need to test the board components. That all said here we go!

I have a Panasonic tc-p58s2. It has the 7 blink error when powered up. When I disconnect the power and ribbon cable from the SC Board, then I had 6 red blinks. I hooked the SC Board back up and disconnected both the SU and SD boards and then powered the unit up. Then I still received the 7 blinks. I wanted to check if this means that I have isolated the SC Board as the issue?

I saw on another post on here: https://www.badcaps.net/forum/showthread.php?t=36114

This lead me to believe that the SC board is most likely at fault, or the buffer boards (which I am not sure what those are)

If the SC Board is the likely culprit can anyone help advise me on what testing should be done to find out what the problem components are? If any additional pictures or close ups of a certain part of the board are needed please let me know. Thanks in advance for any help! It will be greatly appreciated.

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

did you follow the sd/su isolation test with sc50 jumpered?

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

download manual from here. that should help identify boards etc



Once you've done the isolation test if it passes it's the buffer boards. fail then it's Sc which there's a good chance or worst case could be both sc and buffers

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

this would be your safest option for $72

http://www.moduslinkptstvboards.com/txnsc1lyuu/

[engelwood39]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

did you follow the sd/su isolation test with sc50 jumpered?

Yes I did jumper the sc50 pins.

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

well then the fault is SC if you still had 7 blink with the sd/su disconnected and sc50 jumped. you now need to check the buffers(sd/su boards) for shorts.

go to the block diagram in the manual and find where it shows the sc sd su boards

identify the pins for Vfo, VSCN-F, & 5V_F on the sd and the su boards. disconnect the small ribbon between the sd/su

then measure the resistance for each of those points on each board and post them up. you'll need a meter that get go to about 5-6 meg

measure reference is vfg which are those metal plates on the buffer boards

[engelwood39]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

If I use this method for testing and find that both the SU and SD reading a few shorts from the ground screws after I already did the SC isolation test with a fail does that mean I most likely have a bad SC, SU, and SD?

https://www.youtube.com/watch?v=k0EZHBr4dMQ&app=desktop

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

If I use this method for testing and find that both the SU and SD reading a few shorts from the ground screws after I already did the SC isolation test with a fail does that mean I most likely have a bad SC, SU, and SD?

https://www.youtube.com/watch?v=k0EZHBr4dMQ&app=desktop

yes, I would test the buffers disconnected from the sc. did you get a constant continuity beep or are you yet to try it?

what happens with vfo to the same gnd point?

[engelwood39]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

yes, I would test the buffers disconnected from the sc. did you get a constant continuity beep or are you yet to try it?

what happens with vfo to the same gnd point?

I did disconnect the SU and SD boards when I did this test and I was getting some pins that were showing short and and some that were not on each of the 4 ribbon cable connectors.

Your question "what happens with vfo to the same gnd point?" Could you please help me out a little more on what the vfo is? I am sorry for my lack of knowledge and thanks for all the help!

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

I did disconnect the SU and SD boards when I did this test and I was getting some pins that were showing short and and some that were not on each of the 4 ribbon cable connectors.

Your question "what happens with vfo to the same gnd point?" Could you please help me out a little more on what the vfo is? I am sorry for my lack of knowledge and thanks for all the help!

does not sound promising, that's bad luck, normally the buffers survive but this can happen. I've had it myself.

see if you can make sense of the image I've created

[engelwood39]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

does not sound promising, that's bad luck, normally the buffers survive but this can happen. I've had it myself.

see if you can make sense of the image I've created

On the SU between pin between pin 2 and Vfg it is shorted. On SD board and pin 1 it does not show a short.

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

On the SU between pin between pin 2 and Vfg it is shorted. On SD board and pin 1 it does not show a short.

ok, so are you able to measure resistance at the SD42 pin1 and recheck that there are shorts between the gng plates and the outputs pins. Normally if output short , Vfo shows short but maybe it has low resistance just not low enough to trip the continuity beeper.

[engelwood39]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

ok, so are you able to measure resistance at the SD42 pin1 and recheck that there are shorts between the gng plates and the outputs pins. Normally if output short , Vfo shows short but maybe it has low resistance just not low enough to trip the continuity beeper.

Are the output pins the pins he tests in this video?
https://www.youtube.com/watch?v=k0EZHBr4dMQ&app=desktop

If so both boards show that there are shorts. Does this mean that both boards are bad?

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

Are the output pins the pins he tests in this video?
https://www.youtube.com/watch?v=k0EZHBr4dMQ&app=desktop

If so both boards show that there are shorts. Does this mean that both boards are bad?

if you followed that then afraid so, rare but it happens. I've had a 50v20 have both sd/su and sc all shorted and it's essentially the same deisgn/generation as yours just upspecced a little.

[engelwood39]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

Sorry guys, I've been in Florida on vacation the last week. I was wondering what my options are for the su snd sd boards? I found an su board on ebay for $75 but could not find an SD board any where. Can any of these parts be bought from Panasonic?

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

you may have no choice but to send all 3 boards to moduslink for repair. Not sure how good their buffer repairs are but $60 each for repair + the SC. I think this way if it goes all bad you have a wty. $75 for one board and still searching for another + the Sc repair i think if it's lumped on moduslink then at least they'll test everything and should not leave any ?? on which bit was good or bad etc

[tw2005]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

these are probably no longer available new, maybe try https://www.encompassparts.com/item/...RD?language=EN

but given that recycled price is higher than new I would not be optimistic

https://www.encompassparts.com/item/...1LYUU/Pc_Board

[engelwood39]

Re: Panasonic tc-p58s2 SC, SU or SD Board issues

Okay... I was finally able to the SU and SD boards on Ebay for a justifiable price. I also found and bought a SC board, (It is the same board number) but it has different style plugs that go to the SU & SD boards (I didn't know this when I purchased).

I know the old SU and SD boards were bad because they showed shorts on multiple pins on the ribbon connector to ground. When I power the TV up with either of the 2 SC boards I have and leave the SU and SD boards disconnected from the SC board I get a 7 blink code. I don't see an led light up on my old board, but I do see a green led light up on the new board.

On the Service manual it says 7 Blinks are SU & SD board (check points) It says 6 Blinks is SC (check point)

What I want to know:
-What does the 7 blinks mean when the SC is not connected to the SU & SD boards?
-Is it safe to try the new SU & SD boards with the old SC board that has no led lighting up?
-If that's not recommended should I desolder the pin connectors out of the old SC board and put them into the new SC board that has a green led but slightly different pin connector?

Please advise