Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

[rocky_mtn]

First let me mention, I know there has been tons of threads on this topic, and I've searched under this particular sub-forum, under my TV model and have read them all. So I apologize in advance if anyone feels this has been covered. My neighbor was throwing away his plasma and I felt compelled to save it from the dump. I'll also mention the panel itself looks to me, to be in perfect condition. I've done days of research on this and followed the flow chart on the diagnostic manual and it told me to replace the SC board to remedy my 10 blink code. My old one was dead in the water, no green LED or anything. Power supply seems okay to me and fans spin up until the TV clicks off. Ordered a refurbished replacement SC board that arrived today so I installed it. I probably made a mistake not disconnecting anything downstream of the SC board (buffer boards and panel) but now its a little too late for that. So my blinking changed from 10 to 7 and the green LED IS working on the new SC board. I've tried isolating the buffer boards to see if I can get any change in the blinking and it remains 7 no matter what. I'm prepared to purchase a couple new buffer boards to throw in it, but I am nervous I've ruined my new SC board already. I disconnected the buffers and jumpered SC50 to see if the SC is bad and checked SC2 for shorts. No shorts and remains 7 blinks. Is there anything that I'm missing here? I also did the resistance checks as follows :
Using a digital meter
measure the resistance
between VF-ground
(Floating ground) and
pin 2 of connector SU41
on the SU board.
The normal resistance
should be approximately
2.1Mega-ohms.
Note: A low resistance
reading indicates a
defective SU board.
I got .799M ohms with meter set on auto black to ground red to pin 2, swapping the leads red to ground black to pin 2 yields 18.50M ohms

Using a digital meter,
measure the resistance
between VF-ground
(Floating ground) and
pin 9 of connector SD42
on the SD board.
The normal resistance
should be approximately
2.1Mega-ohms.
Note: A low resistance
reading indicates a
defective SD board.
I got .799M ohms with meter set on auto black to ground red to pin 9, swapping the leads red to ground black to pin 9 yields 19.80M ohms

Using a digital meter measure the
resistance between the VF-ground screw
(Floating ground) and pin 3 of connector
SC42.
Also measure the resistance between
the VF-ground screw (Floating ground)
and pin 5 of connector SC42 on the SC
board.
The normal resistance for pin 3 is
approximately 2.9Kilo-ohms and approx.
5.7Kilo-ohms for pin 5.
Note: A low resistance reading indicates
a defective SC board.
I got 2.953M ohms on pin 3 and 5.70M ohms on pin 5...seems normal

I guess it just really bugs me that i can't get the 7 blink to change to something else as if im not isolating anything when I clearly am. I really want to fix my first TV. Please help me not waste money and hopefully determine that I haven't wasted the money I've just spent on this new SC board. Thank you so much in advance!

[Hombre]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

Well if you isolated buffer boards with jumping the sc50 and taking out the 4 vfg screws, if the SC is ok set should "turn on" - front led should become solid green. And since you have a 7 blinks that means that SC does not work well, so either you got a bad board, or you killed it with bad buffers.
Check resistance for vsus, 5v (C561 or C563), 15v (tp82).
Check voltages upon powering it up - Vsus, Vda, Vscn, 5V, 15V. But be carefull when doing it , probe can slip easily and make even more damage to the board, or even hurt you.

[tw2005]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

As Hombre has suggested Check Vsus is present at SC2 when it powers up.

[rocky_mtn]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

So this morning with the buffer board's disconnected I powered it up and I get 209.2 vdc @ SC2 for 2-3 seconds and then the voltage dissipates rather rapidly. To be honest, I didn't see in the manual how to check all the other voltages hombre listed to check. Is there a guide for taking these measurements? I'd love to get what I need to replace ordered today if at all possible. Thanks a million guys!

[rocky_mtn]

Re: Panasonic TC-P42S1 - 10 Blinks Replaced SC Board Now 7 Blinks

Upon closer inspection of the refurbished SC board I purchased, who thinks I was sold a bunk board? Pictures attached...see D618

[vinceroger69]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

i would send that board back and get a refund that didodes certainly blown.
Did you do the buffer test? to make sure there ok.

[rocky_mtn]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

I'm not sure exactly what you mean? Could you elaborate? I'll do whatever needs to be done, I just need a little guidance. I've followed the directions in the troubleshooting guide, but I can't seem to get the TV to stay on with isolating boards. I still have my old SC board that I'm going to put back in and I'm presuming the 10 blink will return. Tell me how to test the buffers and I'll do that. I wasn't sure if I could perform the test not having a good SC onboard. Thanks again!

[vinceroger69]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

in post 2 hombre says (so either you got a bad board, or you killed it with bad buffers).
so maybe worth testing the buffers to make sure there ok im sure hombre or tw2005 will advise on how to test them.

[rocky_mtn]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

I hear ya, I'm just not sure if the buffers can be tested without a good SC board in place. But hey, what do I know...literally not much! Ha...thanks sir!

[vinceroger69]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

you should be able to test them with a multi meter im sure someone will advise you on the correct procedure (i have not worked on enough plasmas myself so dont want to advise you wrong) so im sure a more experienced member will advise soon but in the mean time get that board sent back etc as you will need a new one either way.

[rocky_mtn]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

Well the seller issued a refund no questions asked, so I guess that's done. Wish I knew more about figuring out what's wrong with my original board. I could probably harvest parts from the board I purchased and make 1 good board out of 2 since the seller doesn't want his back. There is no obvious visible damage to my original board. I've put my original SC back in and the buffers aren't connected and sc20 is disconnected. Still 10 blinks and no green LED on the board. TV won't stay on. I don't seem to get the 209 vdc at SC2 like I did on the replacement board though. I get a big quick spike up to 400 something and it goes to 0 almost immediately.

[Hombre]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

You can check if buffers are short easily, just watch this video:
https://www.youtube.com/watch?v=51SZsfH60EY

I assume they are ok, but check it, twice

Your old board sounds like dead short on SC connector, "new" one, who knows
Unplug old sc board and measure resistance on SC connector. If shorted (100%) start checking fets, diodes. Start with q661, usual suspect.

You have equipment and some experience with soldering, through hole and smd components will be involved?

[rocky_mtn]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

Tested buffer boards in the chassis, not removed. No pins beep short to ground on either board SU or SD. Unplugged SC2 on old SC board and tested the terminals on SC2 on the actual connector on the board and they do ABSOLUTELY measure shorted. This testing was done with the buffer boards disconnected but the 4 VF_GND screws installed. Q661 is definitely shorted also. I'm thinking about just swapping it with the one from the "new" board and seeing what happens.

[Hombre]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

Well it's not only q661 that is damaged, for sure, so simply replacing that one most probably won't solve anything and there is high posibility that more damage will be done.
And you can test all the others, like q401, 421,etc, diodes, and then regulators, basically you have to check everything for shorts/low resistance.
You can search here TNPA4829 or TNPA4844 or TNPA4872 and see where to check, and how. Alot of good info on the forum.
Measure resistance from TP82 to GND, also C561 to GND, write them down.
You can work parallel with both boards.

[tw2005]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

http://www.ptselectronicsinc.com/txnsc1efuu/

$95

[tw2005]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

Or you gamble with a parts kit which may or may not fix it 100%

Kit example. As you can see it's a reasonably long list of parts

http://www.ebay.com/itm/REPAIR-KIT-T...0AAOSw~OdVW4bh

http://www.ebay.com.au/itm/TCP42S1-T...item2ed4221c77


The safe option is PTS or you start searching and reading other repairs. I had 3 4782 boards I tried. Got all 3 going eventually, only one ran correctly, the other two ran but had maldisharge issues I never worked out.

There may be some info in here that helps but the final result unknown. Could search also TNPA4782 and see what results you get as this board is a smaller version of that.

https://www.badcaps.net/forum/showth...light=tnpa4844

Since your board is not burnt that may be the one to send in to PTS .

You'll need to check with that burnt diode the PCB tracks are still there and not burnt open which commonly happens on the 4782 boards in he same area.

[rocky_mtn]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

Honestly, I think I'm just going to get a replacement refurbished board and try that again. This stuff is just too tiny for me to even get my paws on. Just kinda wished I had a better understandin of it, as I'm sure I could fix it. I just don't have the time or patience haha...thanks guys

[Andrew F. Ali]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

Time and patience are two key words in learning electronic repair.

[tw2005]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

Time and patience are two key words in learning electronic repair.

True, but boy, sometimes you waste too much of one and then run out of the other. That hurts.

[tw2005]

Re: Panasonic TC-P42S1 - 1 Blinks Replaced SC Board Now 7 Blinks

Honestly, I think I'm just going to get a replacement refurbished board and try that again. This stuff is just too tiny for me to even get my paws on. Just kinda wished I had a better understandin of it, as I'm sure I could fix it. I just don't have the time or patience haha...thanks guys

Well, you still have the other bad one to have a crack, if you get one repaired then you have one to compare measurements to.