tc-p50S2 10 blink SC troubleshooting

[allenrw]

Hi all,
I need a few pointers here, I have TC-p50s2 panasonic with the 10 blinks shutdown code that I think I have isolated to the SC board as high current problem but not sure.
I measured sub 1.2v, sub 1.8v, sub 5v before shutdown OK
Found SOS4 line to be odd, it went to 3v just before shutdown.
Read I should check Vsus and Vda and found Vsus to be no more than .7v before shut down.
Disconnected SC and it went to 202v before shutdown but still 10 blinks.
Disconnected SC and S20 and it went to 6 blinks and took longer to shutdown, Vsus stayed at 202v before shutdown.
Reconnected all leads but put ammeter on Vsus going to SC, read low for a second or two then jumped to 1.7 Amps and shutdown.
Pulled sc41, sc42, and sc46 from SU and SD boards and jumpered SC50 and got the same results as above.
I have 368 ohms from pin 1 of SC2 on SC board to ground.
I also checked all the electrolytic caps in circuit with my cap. meter and they seem OK
I don't mind doing board level surgery but I'm hoping someone here has a few pointers.
Thanks Bob

[tw2005]

Re: tc-p50S2 10 blink SC troubleshooting

The SC definitely is bad. 368 ohms at SC2 is as good as a short.

When you disconnected the SC with 202V Vsus but still 10 blinks was that with SC2 disconnected but the SC20 (ribbon)still connected?

The P5V and P15V lines on the SC could also be shorted.

Either way it's the SC. The cct is very close to the TNPA5081 I've fixed, the S2 uses the same SD/SU boards except yours has no heatsinks I believe.

I would also check out the SU/SD boards as well in case they have an issue also

http://www.ebay.com/itm/YSUS-BOARD-F...item417522f79c

http://www.ebay.com/itm/Genuine-PANA...item27d4c9923d

http://www.ebay.co.uk/itm/PANASONIC-...item2a2f7b01c6 contact to check postage

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

Tnx for reply
This is how I tested it. also found Q401 and Q402 shorted.
"Disconnected SC and it went to 202v before shutdown but still 10 blinks.
Disconnected SC and S20 and it went to 6 blinks and took longer to shutdown, Vsus stayed at 202v before shutdown.

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

Following tw2005's advice I checked the P5V and P15V lines. P5V no shorts. P15V was .9 ohms to gnd.
I found Q521, IC521 bad (pretty sure, by resistance tests while in circuit)
Then found Q421 and Q422 shorted, so now I'm thinking what caused all this?
The VFG and VOL lines both blew their output transistors, by looking at the block diagram I don't see how they are connected to the SU, SD boards but then I'm not done investigating this yet.
Still ramping up to test the SU, SD boards and thinking that the maybe I should look at the power circuits on SC (16V_F and Vad+5V and what else?)
What about the A board, should I look there too?
Bob

[tw2005]

Re: tc-p50S2 10 blink SC troubleshooting

I'd forget about the A board.

https://www.badcaps.net/forum/showthread.php?t=26322

For Q521,

https://www.badcaps.net/forum/attach...5&d=1371789568

IC 521 I'd consider removing and measure pins 11,15 low ohms is no good. Also across 7 & 8 if open or short bad, then re check P15V whilst IC521 is out and see what it reads.

Those replacement boards are not too badly priced which would be the safest way to get this going, but if you're a risk taker, have a go at component.

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

tw2005 when you say "Those replacement boards " which ones are you talking about? SD, SU or SC too.

I will probably buy the replacement components for the SC board which currently stands at Q401, Q402, Q421, Q422, Q521, and IC521, it doesn't look like it will break the bank.
Then I will test it all with SD and SU disconnected and SC50 jumpered all the while monitoring the amperage on Vsus to SC. Then I'll plugin SD and SU and see what changes amperage wise, maybe bring it up with my variac to catch a high amps condition before it is destructive. I will check every power supply output I can find so I know if there are any other issues.

TW2005 where did you get that replacement for Q521 from? All I got off the transistor was 3Y0G4 which didn't cross to anything so far.

[tw2005]

Re: tc-p50S2 10 blink SC troubleshooting

tw2005 when you say "Those replacement boards " which ones are you talking about? SD, SU or SC too.

I will probably buy the replacement components for the SC board which currently stands at Q401, Q402, Q421, Q422, Q521, and IC521, it doesn't look like it will break the bank.
Then I will test it all with SD and SU disconnected and SC50 jumpered all the while monitoring the amperage on Vsus to SC. Then I'll plugin SD and SU and see what changes amperage wise, maybe bring it up with my variac to catch a high amps condition before it is destructive. I will check every power supply output I can find so I know if there are any other issues.

TW2005 where did you get that replacement for Q521 from? All I got off the transistor was 3Y0G4 which didn't cross to anything so far.

I'm referring to the 3 Ebay listed SC boards.

Q16521 B1HFPFA00001 TRANSISTOR 1 CPH5524-TL-E

I pasted my repair link because there is a lot of part info in there for you.

Some of these will match up if you cross reference your parts list with these numbers.

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 DG502LW
Q16403 DG3D5020CSLW TRANSISTOR 1 DG502LW
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

Your parts. Is that the final tally for shorted IGBTs? Was Q16661 ok? Also check IC16771 & IC16724

Q16401 DG3D5020CSLW TRANSISTOR 1 DG502LW
Q16402 DG3D5020CSLW TRANSISTOR 1 DG502LW

Q16421 B1JAEP000014 TRANSISTOR 1 RJP43F4A ( Could use panasonic IGBT DG402RP, that's what I have there and cct is identical)
Q16422 B1JAEP000014 TRANSISTOR 1 RJP43F4A

Q16521 B1HFPFA00001 TRANSISTOR CPH5524-TL-E

IC16521 C0ZBZ0001708 IC M81737FP

http://www.ebay.co.uk/itm/PANASONIC-...item25757b42b3

If you purchased http://www.ebay.com/itm/Panasonic-TC...item2ec8ea9357

that will give you 1 M81737FP and about 5 CPH5524 plus some other parts that are also located on the SC, which you don't need it appears but could be handy. That's what I did to get CPH5524 because it was actually cheaper than trying to get MOUSER to deliver to Australia and I picked up some extra spares from this board as well.

UTSOURCE http://www.utsource.net/

http://www.ebay.com/itm/DG502LW-Manu...item5651a62b05

http://www.utsource.net/ic-datasheet...A-1906272.html

http://www.ebay.com/itm/DG402RP-Manu...item1e76684b2f

http://au.mouser.com/ProductDetail/O...kZT5xRAlMC/A==

http://www.ebay.com/itm/M81737FP-Man...item1e7c379027

OEM

http://cceparts.com/ProductDetail.as...PPDG3D5020CSLW

http://cceparts.com/ProductDetail.as...PPB1JAEP000014

http://cceparts.com/ProductDetail.as...PPB1HFPFA00001

http://cceparts.com/ProductDetail.as...PPC0ZBZ0001708

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

Thanks for the list.
I checked the other suggested devices
Q16661 shorted
IC16771 shorted
IC16724 ok
Did some poking around and not necessarily done
Q16701 or something near it shorted
IC16773 or something near it shorted
Still need to pull these items to see what exactly is wrong but it is leaving me wondering if I'm chasing a catastrophic and/or display failure here.
I really haven't analyzed what all these failures might be connected to and being there is no info about the SD, SU cards in the service manual it is hard to determine how they interact or even how to test them.
Any know a test for these boards? sd/su that is

[tw2005]

Re: tc-p50S2 10 blink SC troubleshooting

Well my only suggestion is you have a good slow read through my entire post. Since I've repaired three of these there's enough info to give you a good idea including resistance checks on those buffer boards.

But my parts list is something I'd pay close attention too as a good guide to the majority of parts that can fail. My last board blew out to about 32 parts in total but mainly because I missed some items and because the short had gone at the vsus the shutdown cct did not turn it off until it applied power and further damaged the board which complicated the whole process.

It took me a lot of time to work it out and unless you get it right the first time it quickly becomes a more expensive exercise than a replacement board.

IC16771 & IC 16773 will both show shorted because the 5V reg feeds that Inverter IC. You need to make sure that entire inverter cct and the 5v reg are 100% to stop Q16661 from shorting again & again if you miss anything will also blow other things if powered up with anything missed and for me created a real challenge.

Q16701,16702, 16818, IC16771,16773, R16707, & D16702 all need to be checked or replaced and this should stop Q16661 blowing.

All 3 boards IC16773 had failed shorted. With those 2 regulators, I got tricked up on one board for IC16724, input resistance was correct at 2.6k in cct, did not check output which I found much later also was 2.6K, should be much higher so essentially I had 15V coming out instead of 5V.

That 5V is fed to the buffer boards. On the 2 SC with bad IC16724, the buffers were also bad and the 5V lines on them were shorted too.

The other trap with my last board was IC16771, input and output resistance looked ok in cct. However, after blowing Q16661 several times and having replaced everything else and still having Q16661 blow I got suspicious of that reg and decided to pull it out. Input was fine, output open, so no 5V to the inverter and bang Q16661 blows.

You'll read all about it in my post.

Post 22, 29, are 2 successful repairs. 82 on is my long battle and the long list of parts was a result of the stuff ups.

The first 2 were relatively quick, easy and cheap

Post 58 for buffers, if the results don't match exactly, swap the probes around it does affect the measurement.

If you download a manual for any of these and check out the schematic of a TNPA5081 in comparison to yours which may help you correlate my info to your board.
TC-P5032C
TC-P50G20
TC-P50G25
TX-P50G20B
TC-P50GT25
TH-50PF20U
TX-P50G20B

Also have a good look all around the area of IC16521, there for shorted diodes, blown or out of tolerance resistors, Q16451,R16451, Q16551,D16451,D16482.

Looking at your growing list I'm also expecting maybe Q16621. what transistor have they used there? With mine they have a pair of 30F125 IGBTs, looks like they've gone with only 1 IGBT there with yours otherwise the surrounding components look the same.

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

I wasn't aware that that list of parts was what you had to replace or I would have looked deeper.
I have read most of your repair thread now and see the sd/su tests so when I dig back into this tomorrow I'll have a bunch of things to check.
Thanks for your input, it helps me move forward and hopefully save some steps +

[tw2005]

Re: tc-p50S2 10 blink SC troubleshooting

Yeah, hard to believe but that one was a real disaster. Only persisted because I'd invested so much time and money into it. The biggest battle was decyphering the SMD components since the Panasonic codes tell you nothing except when ithey are actually produced by them.

Did not see the point in quitting and learning nothing.

i hope it helps people fix there boards in some way. I very much doubt you will need all those parts, it's quite cheap to fix them compared to buying them if you get it right.

Look forward to see what you find. It was really interesting to see just how close the TNPA5105 was to my board. I'll have a guess and assume your TV uses less power. Might explain why the SC is reduced slightly and the buffers with no heatsinks.

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

To recap
Q16401 shorted
Q16402 shorted
Q16421 shorted
Q16422 shorted
Q16521 not sure if it was shorted but will replace anyhow
IC16521 again not sure if it was shorted but will replace anyhow
Q16661 shorted
IC16771 shorted
Q16701 shorted
IC16773 shorted
IC16501 not sure if it was shorted but will replace anyhow
Q16702 shorted
IC16661 removing this cleared a ~500ohm path 16V_F to VAD
C16708 lost during testing, gawd these things are small and hard to hold!
R16900 tested 3.9k in circuit supposed to be 10k
I test a number of capacitors that had 200 to 500 mF in circuit and were correct out of circuit. I started not pulling these caps if they weren't shorted, I didn't find a single shorted cap.
I ohms, diode or capacitance tested every device that was connected to the bad parts and found nothing else.
I used TW2005's SU and SD readings for his cards (different from mine some) and found enough differences to make me consider getting new/used ones (they are pretty cheap).
So I will most likely order all these parts and see if it goes.
I have considered applying, with current monitoring/limiting, 15 and 5 volts to SC20 and see what happens before giving it an installed full power test.
The question that still remains is what caused all this? I haven't had time to see what the common thread may be.
Anyhow the beat goes on, stayed tuned for the continuing saga.
TW2005 thanks again for your input, I probably wouldn't have gone this far without the direction you provided.

[tw2005]

Re: tc-p50S2 10 blink SC troubleshooting

Do me a favour and list what you did get on the buffer boards for resistance.

[tw2005]

Re: TC-P50S2 10 blink SC troubleshooting,TNPA5105 repair

Q16401 DG3D5020CSLW TRANSISTOR 1 DG502LW shorted
Q16402 DG3D5020CSLW TRANSISTOR 1 DG502LW shorted

Q16421 B1JAEP000014 TRANSISTOR 1 RJP43F4A shorted
Q16422 B1JAEP000014 TRANSISTOR 1 RJP43F4A shorted

Q16521 B1HFPFA00001 TRANSISTOR CPH5524-TL-E not sure if it was shorted but will replace anyhow ((Pins 2-3 & 1-5 , 2-3Mohms from memory(I'm not shouting))
IC16521 C0ZBZ0001708 IC M81737FP again not sure if it was shorted but will replace anyhow (Good idea, did you check the Vcc-gnd resistance, how did P15V resistance right after this was removed? If still funny,NAND GATE cct, IC16691,Q16647 last board both those were failed)
Q16661 B1JAER000010 TRANSISTOR 1 RJP63F3A shorted(every board this was failed)

IC16771 C0CBADC00072 IC 1 78L05L, TA78L05F shorted(shorted out of cct too? 1 of 3 boards this was bad)

Q16701 B1ADCN000007 TRANSISTOR 1 MMBTA92 shorted
Q16702 B1ABCF000231 TRANSISTOR 1 2PD601ART,215, 2SD0601A0L shorted(every board this was failed)

IC16773 C0JBAB000715 IC 1 Toshiba TC7SH14F shorted(every board this was failed)

C16708 F1H1H104A970 C 0.1UF, K, 50V, lost during testing, gawd these things are small and hard to hold!


IC16501 C0ZBZ0001708 IC M81737FP not sure if it was shorted but will replace anyhow

IC16661 C0BBBA000024 NJM2903V(TE1) , removing this cleared a ~500ohm path 16V_F to VAD (very surprised to see this on the list, no problems on mine but did remove and compare to a known good one, wish I had not with the soldering)

R16900 D0GB103JA057 M 10K OHM J 1/10W , tested 3.9k in circuit supposed to be 10k(so out of cct it was? It all ties in cct ,part of which heads down to shorted Q701,702,IC773 so that may be the real issue?)

Green part numbers are also on that SS board I mentioned for scavanging.

M81737FP Qty 1
NJM2903 Qty 1
CPH5524 qty 5
F1H1H104A970 0.1UF, Qty 3
D0GB103JA057, M 10K OHM J 1/10W Qty 3

My very first repaired board, my post #22 is very close to the fault profile of your board.

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

I'll post the buffer board info tomorrow I hope.

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

Attached are the buffer board measurements

[tw2005]

Re: tc-p50S2 10 blink SC troubleshooting

Attached are the buffer board measurements

yeah, I'm a little baffled by those. Vscn_F is spot on.

But the others don't match but they all read the same on both boards.

from the few boards I've had a chance to test, at least something generally shows short.

When I tested mine they were removed from the TV. i don't think having them hooked to the panel would matter but a couple of questions.

1 Were they disconnected from the 3 SC connectors/
2. earth screws removed?
3. interconnecting ribbon disconnected between SD & SU boards?
4. try again and reverse the probe polarity and recheck results?

Two figures i could get consistantly were Vfo 1.8Mohms and Vsc_F at 220kohms.

I just found some more results from my brothers TV and that had bad SD,SU,SC.

On that one I have 500-600K on 5V_F on the SD board, 2.3Mohm on SU but both had shorted Vfo (1.8M normally) Vscn_F on both of those dead short.

if you can't get 1.8M or so on the Vfo and 5V_F is still only 100'sKohms then yeah I tend to agree there's enough difference to bail out and find some good ones.

With my brother's TV buffers as they were I got lazy and did not test them assuming they were going to be good like mine.

End result was blowing up a brand new SC.

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

The boards were out on the bench connected to the meter only and disconnected from each other.
I tried changing leads some and I don't think the results varied.

[tw2005]

Re: tc-p50S2 10 blink SC troubleshooting

The boards were out on the bench connected to the meter only and disconnected from each other.
I tried changing leads some and I don't think the results varied.

Best get fresh ones then, I could'nt think of anything worse if we get that SC going only to kill it with the buffers.

At least you can run that SC up with the bypass in the meantime without them.

[allenrw]

Re: tc-p50S2 10 blink SC troubleshooting

So the price and availability of parts is now the problem.
I am having trouble finding all of them and the ones I have found are from different vendors so there are shipping costs added.
A used guaranteed board is about 120 dollars US and SU/SU boards are 12-20 dollars US.
The tv costs 500 dollars US new.
Bottom line is I need a cheaper source for the parts.
Any ideas?