Panasonic sc tnpa5081 rebuild

[tom66]

Re: Panasonic sc tnpa5081 rebuild

tw2005, does that FET frying also kill the Q16701 and nearby resistor? Wow. That is further than I would have otherwise expected.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

tw2005, does that FET frying also kill the Q16701 and nearby resistor? Wow. That is further than I would have otherwise expected.

With the initial fault probably not but with a failed repair and powerup I'm going to say most likely. 2 out of 3 boards had Q701 s/c, the resistor vaporised when I powered the partially repaired board.

Definitely the energy escaped via 3.9k R707 on my board, it was a nice blue flash. I suspect this is where his board will be now.

All those bits are cheap as chips so it's probably just as smart to replace anything doubtful. The 30V FET and 80V diode there I missed several times as neither were dead short and in cct I found tricky to detect.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

only last board had bad opto

[davidjamesi]

Re: Panasonic sc tnpa5081 rebuild

Dang i got a bad TNPA5081 board on my tc-p50g25, just from a couple tests most of the fets you listed are toast. What a pain in the butt, appricate all your hard work and for sharing it, ill prob start on my rebuild X-0

[ted_ge]

Re: Panasonic sc tnpa5081 rebuild

tw2005 Thank you for the reply.
B/N
I removed the IC773 and IC771 and still get 26ohm b/n Vout and Com (where IC771 should be) ?!?!?????
Thank you in advance

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

tw2005 Thank you for the reply.
B/N
I removed the IC773 and IC771 and still get 26ohm b/n Vout and Com (where IC771 should be) ?!?!?????
Thank you in advance

I'll have to have a look at the schematic and see what else hangs of the 5v supply from that regulator. I know that there were several other items i removed first before finding the inverter was shorted.

the fact you only did the IGBTs means power would have been applied to a shorted cct so further items have most likely failed which is how i ended up with such a job with the first board I attempted(last one fixed)

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Actually i'm getting my 5v lines mixed up, it was the P5v at SC20 I had to remove a lot to find the short.

IC771 Vad +5V supplies, PC16461 (OPTO), IC773(inverter), Q16649 (also connects to the NAND )

Look at post #120, pay close attention to circled items, maybe remove the opto first and see if any change, check all those other transistors for shorts, check resistors and diodes.

I'd consider straight out rebuilding that inverter cct, was IC773 gnd-vcc low ohms out of cct?

In cct on a good board about 6k ohms com-Vout on IC771, must check reg out of cct, in case it's bad , k ohms on input, M ohms on out ( from memory)

What resistances did you get on the removed 5v reg pins?

The time zones are not good for us, currently 5.24pm wed here, you're 12.54am WED. So at 11pm it will be 6.30am for you.

[ted_ge]

Re: Panasonic sc tnpa5081 rebuild

tw2005 Hi,
I naturally did not check the resistance on the removed IC773 before trowing it away. When checking the 5v supplies (before prematurely plugging the AC again I found the 26ohm on the Q771 and then found the same on the inverter...
You read my mind: start removing the components involved in the 5v/inv cct.
I appreciate the list of the components you have replaced in your repairs as well as the great pics on p120
Should I suspect IC16501 and/or IC16521 OR begin with the supporting parts?
Thank you for your time. Hopefully, we will solve this one.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Pity about IC773, I was just curious to compare if it had failed, most likely has, every other one had so far.

I'd attack this one section at a time, it's a balance between repair cost against risk. You could replace everything or try and work it out. Fixing it first go though is a lot cheaper.

The list at least points you to what can fail.

IC16521 could be good or more than likely bad, IC16501 so far I have not struck that failed yet.

I would check every part around IC16521, They're all circled on that board shot what I replaced. Only on the last board I messed up did I have to replace more than IC16521 there which you may also be in the same situation.

Measuring the P15v line in will possibly give a clue but I have had one which was ok there but pins 7 & 8 were open cct but that was on the one I kept blowing. usually the Vcc - gnd goes low on the failed ones I had. Straight out replacing that is a safer option and to test pins 7 & 8 it is better removed to test so you might as well put a new chip in and the best option for that.


Q771 will show low as will anything else on that 5V line until you find the short, I would not throw anything out yet unless you're happy spending the money on parts some of which you may have to get from a Panasonic stockist like Sears or CCE etc.

Maybe go through all the posts and copy into an excel spreadsheet all the tests and parts replaced, annotate what you find or queries so you can keep track.

That way you can post it and I can see what's going on.

after the second blow up, what was the result damage wise for all the IGBTs? It'll help me understand where your board may be at.

Also, Texas instruments have direct replacements for those Toshiba Inverter & NAND ICs. Watch the part numbers size wise as the NAND is a smaller package than the Inverter when ordering bits. They're a few sizes for the same device.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Well my voltage regulators that I borrowed arrived so my donor board is still alive.

IC491, IC792 NJM2406F which I could not make my mind up were good in the end. The suspect ones i decided to install back into this one and all is good, so I'd ignore them as required for the last board repair.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

tw2005 Hi,
I naturally did not check the resistance on the removed IC773 before trowing it away. When checking the 5v supplies (before prematurely plugging the AC again I found the 26ohm on the Q771 and then found the same on the inverter...
You read my mind: start removing the components involved in the 5v/inv cct.
I appreciate the list of the components you have replaced in your repairs as well as the great pics on p120
Should I suspect IC16501 and/or IC16521 OR begin with the supporting parts?
Thank you for your time. Hopefully, we will solve this one.

I should have check your info, there is no Q771, I think you mean 701 which would be high on my suspect and expect shorted along with 702.

Since you removed the inverter, is Q701 shorted or removed to fault find that low resistance yet?

The IC771 5V reg I'm going to keep on about it, The only way be 100% is to remove and test out of cct because the output should show Mohms but the load in cct is about 6kohms. So if it has an open cct on the output then it will still read the 6K , No 5v=no inverter and you'll keep blowing the IGBTs.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Somone has just started a TNPA5081 repair service on Ebay in the UK.

[tom66]

Re: Panasonic sc tnpa5081 rebuild

A recent rash of cheap TNPA5081 have popped up:
http://www.ebay.co.uk/sch/i.html?_sa...pa5081&_sop=15

I need to find me a faulty G20 then...

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

A recent rash of cheap TNPA5081 have popped up:
http://www.ebay.co.uk/sch/i.html?_sa...pa5081&_sop=15

I need to find me a faulty G20 then...

Which one's the cheap one? I only see worldwide listed unless I go hunting in UKEbay which I have not for a while.

I'm a little overstocked now, 4 spare

Actually the 24GBD one is a good deal, I'd normally grab a spare at that price, Oh hang on I tried that and got faulty board.

I joked with the MRS once I completed that last difficult board we'd see some Ebay Repair service pop up since everyone can read this forum. Google TNPA5081 and the rebild thread comes straight up.

I think they refer to this as paranoia

Anyway I hope the price comes down, still pricey for the kit and the exchange repair . At least we should not run out of SC boards for these unlike the generation before.


Oh, and TOM there was one 50" here which the seller cancelled on Ebay which only had a 99c bid comingup to closing. Something tells me they were not happy with a single bid. Wish I was back in Newcastle, could have snapped that and had it fixed with the stock I have,

[ted_ge]

Re: Panasonic sc tnpa5081 rebuild

I should have check your info, there is no Q771, I think you mean 701 which would be high on my suspect and expect shorted along with 702.

Since you removed the inverter, is Q701 shorted or removed to fault find that low resistance yet?

The IC771 5V reg I'm going to keep on about it, The only way be 100% is to remove and test out of cct because the output should show Mohms but the load in cct is about 6kohms. So if it has an open cct on the output then it will still read the 6K , No 5v=no inverter and you'll keep blowing the IGBTs.[/QUOTE]
---------------------------------------------------
It is IC771 instead of Q711(typo).

Q701 tests good on pcb and removed. Even on board Q701 shows good (high R) with the short on inv/IC771 .

On board between pin 7-8 IC16521 - 220kohm, IC16501- 440km --> too high to be bad ?

When plugged in before replacing the inv only Q1661 from the IGBTs sorted

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

I should have check your info, there is no Q771, I think you mean 701 which would be high on my suspect and expect shorted along with 702.

Since you removed the inverter, is Q701 shorted or removed to fault find that low resistance yet?

The IC771 5V reg I'm going to keep on about it, The only way be 100% is to remove and test out of cct because the output should show Mohms but the load in cct is about 6kohms. So if it has an open cct on the output then it will still read the 6K , No 5v=no inverter and you'll keep blowing the IGBTs.

---------------------------------------------------
It is IC771 instead of Q711(typo).

Q701 tests good on pcb and removed. Even on board Q701 shows good (high R) with the short on inv/IC771 .

On board between pin 7-8 IC16521 - 220kohm, IC16501- 440km --> too high to be bad ?

When plugged in before replacing the inv only Q1661 from the IGBTs sorted[/QUOTE]

I'm away all week so I don't have access to a board to compare and a lot of my resources.

So Q701 is good, Q702 is ??, what's the resistance now for the 5v supply to it? I am getting confused where you're at. Is it still low ohms with the inverter and 5v reg out?

It should be about 6K although I do have one which was 4K but still operates correctly.

Has the schmitt inverter been replaced yet?

Pin 7-8 could be ok but won't know without checking when I get back. I do know that they both read different in cct.

What's the resistance between pin 15 & gnd (pins 9,10,13,15,16) or across D790. That's the 15V supply to those FET drivers.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Ah TED_GE, I did not see the tiny image attachment in post #135. What manual/schematic are you using?

That is not a TNPA5081 schematic. Looks like the series before, G10 maybe??

[davidjamesi]

Re: Panasonic sc tnpa5081 rebuild

Theres someone on ebay selling kits to repair the TNPA5081 board for around what you can get them used for...crazy http://iurl.no/5b1s4

Appreciate all your work guys, im going through my board right now, it died couple weeks ago! And there are no boards in the US. so gotta fix it myself i guess
Did you have a more updated parts list of all the stuff you replaced/checked?
Thanks again.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

post 119 would be a good place to start, unlikely you'll need all those, shorted IGBTs are a no brainer.

Measure resistances at SC20 P15V, P5v, the two 5V regulators and list what IGBTs are dead.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

I've highlighted ones here which stuffed me up trying to test in cct.


D16451 B0ECKP000055 DIODE 1 ROHM , RF101L4S 400V 1A SHORT
D16482 B0FACP000003 DIODE 1 RFN25TM4SWSHORT
Q16452 B1JAEP000012 TRANSISTOR 1 GT45G128SHORT
D16702 B0ACCJ000048 DIODE 1 MA2J11100L 80v 100ma switching diode?
IC16521 C0ZBZ0001708 IC 1 M81737FP
IC16561 C0JBAU000088 IC 1 PAVCTH c541 buffer ic
IC16562 C0JBAU000088 IC 1 PAVCTH c541 buffer ic
IC16563 C0JBAB000916 IC 1 c14 INVERTER
IC16691 C0JBAC000363 IC 1 TC7SH00FU(TE85L,J
IC16724 C0CBADE00049 IC 1 BA178M05FP-E2
IC16771 C0CBADC00072 IC 1 78L05L, TA78L05F
IC16773 C0JBAB000715 IC 1 Toshiba TC7SH14F, marking HA, Schmitt NOT

PC16461 B3PBE0000054 IC 1 PS9856-2-F3-AX
Q16402 DG3D5020CSLW TRANSISTOR 1 DG3D5020
Q16403 DG3D5020CSLW TRANSISTOR 1 DG3D5020
Q16421 DG3D4020CSRP TRANSISTOR 1 DG3D4020
Q16422 DG3D4020CSRP TRANSISTOR 1 DG3D4020
Q16521 B1HFPFA00001 TRANSISTOR 1 CPH5524-TL-E
Q16551 B1HFPFA00001 TRANSISTOR 1 CPH5524-TL-E
Q16621 B1JADN000009 TRANSISTOR 1 GT30F125
Q16622 B1JADN000009 TRANSISTOR 1 GT30F125
Q16647 B1CBGD000001 FET 1 2SK3018T106,2n7002
Q16661 B1JAER000010 TRANSISTOR 1 RJP63F3A
Q16701 B1ADCN000007 TRANSISTOR 1 MMBTA92
Q16702 B1ABCF000231 TRANSISTOR 1 2PD601ART,215, 2SD0601A0L
Q16818 B1CBGD000001 FET 1 2SK3018T106,2n7002
R16452 D0GF5R6JA047 M 5.6 OHM,J, 1/3W
R16521 ERJ6GEYJ101V M 100 OHM,J,1/8W 1
R16522 ERJ6GEYJ101V M 100 OHM,J,1/8W 1
R16551 D0GD100JA059 M 10 OHM,J,1/4W 1
R16707 ERJ6GEYG392 M 3.9KOHM,J,1/8W 1