Panasonic sc tnpa5081 rebuild

[Tech 57]

Re: Panasonic sc tnpa5081 rebuild

they shipped it today when i get back i will post pictures
thanks phil

[Stryff]

Re: Panasonic sc tnpa5081 rebuild

I ended up sending my board to PTS, they did an excellent job & I had even removed components before sending it to them... looked factory. Although my board didn't have a burned trace!

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Been busy this week tidying up loose ends on a few boards I had busted but been too lazy to get into it.

Did another 5081 which I'd started which is not ideal if you don't take notes of what's been done.

So result of that was it failed, blowing 90% of the bits I'd just done.

anyway I had forgotten about a couple of resistors that were a bit brown, R421,R422. They were open, so redid the board, replaced those 7.5 ohm gate resistors and this time all good.

First one of these I've done with those bad.

Also I subbed RJP56F4A for the DG502 and no dramas there.

[11alon11@gmail.com]

Re: Panasonic sc tnpa5081 rebuild

I have tried to rebuild 2 boards TNPA5105 and TNPA5081for the TNPA5105 I used the shopjimmy kit and for the TNPA5081 i used the Zentronix kit. Both of the board's will power up and not blow anymore parts but I get the 6 blinks on both with the short on the 50 connector. I have checked and rechecked with no success no parts blow any more but I get the 6 blinks I am at a loss can someone try and help me

[11alon11@gmail.com]

Re: Panasonic sc tnpa5081 rebuild

I have tried to rebuild 2 boards TNPA5105 and TNPA5081 for the TNPA5105 I used the shopjimmy kit and for the TNPA5081 i used the Zentronix kit. Both of the board's will power up and not blow anymore parts but I get the 6 blinks on both with the short on the 50 connector. I have checked and rechecked with no success no parts blow any more but I get the 6 blinks I am at a loss can someone try and help me

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

I have tried to rebuild 2 boards TNPA5105 and TNPA5081for the TNPA5105 I used the shopjimmy kit and for the TNPA5081 i used the Zentronix kit. Both of the board's will power up and not blow anymore parts but I get the 6 blinks on both with the short on the 50 connector. I have checked and rechecked with no success no parts blow any more but I get the 6 blinks I am at a loss can someone try and help me

Did the kits come with instructions or a parts list and locations? Can you post up images of those lists or compile a list of every part removed and replaced?

Did you use every part supplied?

[11alon11@gmail.com]

Re: Panasonic sc tnpa5081 rebuild

this is the list of parts replaced on the tnpa5081 rebuild

[11alon11@gmail.com]

Re: Panasonic sc tnpa5081 rebuild

this is what was replaced on the TNPA5105 on both after replacing the parts I get 6 blinks and no more blown parts with jumper 50 on
R 401 & 402
D451 & 490 & 491 & 618 & 652
D721
Q501 & 521 & 551
Q401 & 402
IC724
Q661
Q601 & 660
Ic501 & 521
Q451
Q421 & 422

[11alon11@gmail.com]

Re: Panasonic sc tnpa5081 rebuild

I also replaced IC771 on the TNPA5105 with no results and checking resistant on the 15v, 5v and sc2 no short, checking voltage on sc20 I do get 5v and 15v and on sc2 about 200v until the 6 blinks when voltage go down

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

That's certainly a big list for the 5081, I would say absolute worst case scenario. The only snags I remember is missing D451 shorted causing 6 blink, or a defective SOS6 detection cct which is unusual but possible and if the onboard LED ios open cct that too will create a 6 blink.

I wonder if you put a part in wrong since you've managed to get the same result on 2 boards?

Interesting to look at that list considering it says it fixes 42C2, 55ST30!, and 54" models which have more transistors

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

this is what was replaced on the TNPA5105 on both after replacing the parts I get 6 blinks and no more blown parts with jumper 50 on
R 401 & 402
D451 & 490 & 491 & 618 & 652
D721
Q501 & 521 & 551
Q401 & 402
IC724
Q661
Q601 & 660
Ic501 & 521
Q451
Q421 & 422

I've done a total of 1 of these. I really should keep a logbook, so hard to figure what I replaced.

looks like D451, R451, Q451, D482(R553?), Q551,R551, IC521

Q421, Q422, Q621, D642, Q401,Q402, Q660, Q661, Q701, (Q702?) IC773,

[Hombre]

Re: Panasonic sc tnpa5081 rebuild

Can you check MID voltage, across those blue capacitors, it should be half of VSUS, so somewhere around 100V, if it is lower than that it will trigger 6 blinks, if everything else looks ok.

[11alon11@gmail.com]

Re: Panasonic sc tnpa5081 rebuild

blue capacitors?

[11alon11@gmail.com]

Re: Panasonic sc tnpa5081 rebuild

Hi I did more work on the TNPA5081 with the 6 blink error and found that the resistant in IC771 center pin to the left is is about 900ohm and in a good board i tested its about 1400ohm any suggestions?
by the way MID voltage is going up to 100v and then down once it detects the 6 blinks

[peteburns]

Re: Panasonic sc tnpa5081 rebuild

Hi all, please does anyone have a list of correct voltage values on this board and/or oscillograms at some important points? I fixed some Samsung plasmas but this Panasonic is too chaotical...My power board looks OK, with VSUS being +208V and Va being +60V roughly, +15V and +5V are OK too, but those output voltages from SC board are mystery - VAD, VFG, VSCN, VOL, MID...It would be nice to test all the IGBT and MOSFET control voltages and make sure they are OK before finally powering the board to VSUS :-) Thank you very much for any info ;-)

[peteburns]

Re: Panasonic sc tnpa5081 rebuild

So MID voltage should be 1/2 of the VSUS, roughly +105V, and VAD is roughly -170V, while VFG is virtual floating GND, pulsating between VAD and VSUS? What about the rest?

[Alastair E]

Re: Panasonic sc tnpa5081 rebuild

check out app-note in my sig. It explains how Plasma sets work.

All the SC is basically is a 6 legged H-Bridge and some floating-supplies and floating driver LV supplies...

[peteburns]

Re: Panasonic sc tnpa5081 rebuild

Thanks for that link, but it explains sustain board working principle in details. In this topic it is more important to describe scan board instead, and, even more importantly - from practical point of view, not theoretical...People don't actually need to know, how exactly the board works, but they need to know, how to examine components, find faulty ones and measure all the important spots in order to make sure all the power devices receive correct signals, so they don't experience big bang while switching on :-) Even the advice of using some resistor or light bulb at VSUS to protect the components is not correct, it will not protect enough and that's not the way any board should be tested...As mentioned many times before, any small overlooked component can cause some signal missing or distorted with the obvious result of immediate bang, or as in tw2005's case after 90min or so - both are not good enough and can be avoided :-)

[peteburns]

Re: Panasonic sc tnpa5081 rebuild

So, the 50" plasma TV works fine again, this time I was lucky, only the SC board was faulty. Just to mention those "100% repair kits" - don't rely on them at all, at least in my case they wouldn't contain all the failed components, meaning the whole board would fail again...

[11alon11@gmail.com]

Re: Panasonic sc tnpa5081 rebuild

I decided to take a look at the tnpa5105 board again with the 6 blinks and found that Zener Diodes 871 and 872 blown. replaced them and now I don't have any blink code and I do have a picture the problem is that the picture is noisy and low in brightness both when I display the menu and picture from HDMI, do you have any idea as to what should be the problem now?