Panasonic sc tnpa5081 rebuild

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

OK. had a bit of a win on about my 20th lap around the cct, pulled into the pits for a think and decided to keep focussing around the areas with known failed parts.

So whilst I've been relying on resistance readings and diode mode, as i've already seen polarity affects the results. So I had red probe on gnd and just went over a lot of stuff already checked.

Went back to the NAND cct IC691, and rechecked Q647, another 2SK3018 (KN) FET and bingo, just like the other gave me a consistant higher reading than normal on one pin. Resistance and the other polarity matched up with all the other boards.

Replaced this FET with a sub 2N7002 and flashing red LED, no SOS, solid green and an energised and humming SC board, great !

Hooked up the buffer boards, repeat of above, screen energised, sound , Ahhh! No picture.

Honestly, give me a break

So I'm left with only one thought and that is the buffer & inverter ICs at SC20?

They were all new ordered OEM from the US using a freight forwarder, however about 2 attempts ago I changed out the C14, inverter from a blown buffer board which I guess is risky and just a sign of pure desparation.

I don't have a Scope which would be of great help in this circumstance but I really need a little guidance here.

i'm hoping everything else is OK and the missing link is the drive signals.

I don't really know what all the control line abbreviations mean so if anyone has a bit of an idea, please sing out.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Just scavanged a C541 buffer IC from a C board, for IC561 & back to SOS7? I'm thinking my soldering skills are being tested with these very fine pitch chips. I did bell the pins out to test the joints, dunno.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

WORKING WORKING WORKING!!!!!!!!!!!!!!!!

I saved one of the original C541 buffers, the one that had not gone short on the Vcc, no idea it was good or not.

Since I had only touched this one chip and went SOS7 again I saw no point putting the one I had just removed so grabbed this little sucker and cleaned it up, put it in.

Powered up with the SC50 jump and it passed. Hooked up the buffer boards and stuff me Back to the Future come up. How fitting.

Honestly, never expected this result.

Family had to get me off the ceiling, i was just a little over excited.

I targetted that particular buffer after tracing the control lines back in the schematic from SD46.

I can only conclude that the new chip got spiked with all the other items I had missed.

The one off the C board was the 3D version boards not fitted to this which had a good SC but the SD was shorted and this was a TV with a cracked panel.

You'd think you would be ok grabbing one from this sort of board but there you go it must have been damaged with the panel.

All I got to do now is source a NJM2406F(TE1) so i can get the working board I borrowed it from back up again.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Another note, D482 which was a RFN25TM4SW and I can't find , I've used a RF2001T3D which is a 100V less and a double diode. obviously it's working with it but would have preferred the same 400V rating. See how it goes I guess.

[tom66]

Re: Panasonic sc tnpa5081 rebuild

Nice one!

As for the abbreviations, my best guesses/implied knowledge:

AA_SIU: ??
AA_CLK: Buffer shift register clock
AA_CERS: Energy recovery something -- possibly
AA_SEL: Buffer enable -- possibly
AA_OC2: Output data control, upper bit (for buffers)
AA_SC_FPGANRST: Fault detection reset feedback for A board FPGA (Emergency SOS, in a vain attempt to save the board from catastrophic damage?)
AA_OC1: Output data control, lower bit (for buffers)
AA_CIS: ?? Output enable for FET drivers maybe?
AA_CEL: Energy recovery low FET/IGBT (ERC)
AA_CEH: Energy recovery high FET/IGBT (ERC)
AA_CSH: Sustain high FET/IGBT
AA_CSL: Sustain low FET/IGBT
AA_CPH1: SUS/ER output pass FET enable
AA_CMH: Set-up ramp drive (VSET)
AA_CML: One part of set-down ramp drive (VAD)
AA_CML2: Second part of set-down ramp drive (VAD)
AA_CRC1: ?? Ramp control bit for crude DAC?
AA_CRC2: ?? Ramp control bit for crude DAC?
AA_CRC3: ?? Ramp control bit for crude DAC?
AA_UHZ: ??

Each buffer chip is a shift register. Recently I realised it probably doesn't make sense for them to have only high or low capability. They probably need tristate capability for many parts of the sustain process. So, the OC1 and OC2 probably serve as data for the two separate shift registers in each IC. OC1 being e.g. the lower level (VSCAN select) and OC2 being the high level (SC board output select.) OC1 and OC2 are chained along the buffer boards, each IC producing a shifted output (relative to how many bits it has, typical 1080p panel having 90 or 64 bits per buffer IC, 12 or 16 ICs.) The CLK is shared for all ICs. Interestingly, there appears to be no RESET pin, like on some LG and Samsung boards, perhaps this is not shown on this diagram.

Will see if I can figure more out at a later time.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Nice one!

As for the abbreviations, my best guesses/implied knowledge:

AA_SIU: ??
AA_CLK: Buffer shift register clock
AA_CERS: Energy recovery something -- possibly
AA_SEL: Buffer enable -- possibly
AA_OC2: Output data control, upper bit (for buffers)
AA_SC_FPGANRST: Fault detection reset feedback for A board FPGA (Emergency SOS, in a vain attempt to save the board from catastrophic damage?)
AA_OC1: Output data control, lower bit (for buffers)
AA_CIS: ?? Output enable for FET drivers maybe?
AA_CEL: Energy recovery low FET/IGBT (ERC)
AA_CEH: Energy recovery high FET/IGBT (ERC)
AA_CSH: Sustain high FET/IGBT
AA_CSL: Sustain low FET/IGBT
AA_CPH1: SUS/ER output pass FET enable
AA_CMH: Set-up ramp drive (VSET)
AA_CML: One part of set-down ramp drive (VAD)
AA_CML2: Second part of set-down ramp drive (VAD)
AA_CRC1: ?? Ramp control bit for crude DAC?
AA_CRC2: ?? Ramp control bit for crude DAC?
AA_CRC3: ?? Ramp control bit for crude DAC?
AA_UHZ: ??

Each buffer chip is a shift register. Recently I realised it probably doesn't make sense for them to have only high or low capability. They probably need tristate capability for many parts of the sustain process. So, the OC1 and OC2 probably serve as data for the two separate shift registers in each IC. OC1 being e.g. the lower level (VSCAN select) and OC2 being the high level (SC board output select.) OC1 and OC2 are chained along the buffer boards, each IC producing a shifted output (relative to how many bits it has, typical 1080p panel having 90 or 64 bits per buffer IC, 12 or 16 ICs.) The CLK is shared for all ICs. Interestingly, there appears to be no RESET pin, like on some LG and Samsung boards, perhaps this is not shown on this diagram.

Will see if I can figure more out at a later time.

F me Tom, lot of work you've done there. But thanks. Sure to help some other brave souls if they read this far.

[tom66]

Re: Panasonic sc tnpa5081 rebuild

Crazy project of the year: Making my own sustain boards.

First I'll made an SS board. To prove I can do it. And then I'll try SC. The SC will be very hard to do, because there are a lot of implied timing specifications etc. for the buffers. So that may not be practical without hundreds of revisions, but the SS should be fairly easy to make.

That is, when I get a donor panel I don't care too much about .

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Well probably not that crazy for someone doing an engineering degree. Someone has to design these, can't wait to see it.

[tom66]

Re: Panasonic sc tnpa5081 rebuild

I'll see if I can do it for my 3rd year Power Systems Engineering course. PDPs fascinate me, driving them is very tricky, but there's a lot to learn from doing this.

[tom66]

Re: Panasonic sc tnpa5081 rebuild

OK, some corrections/additions, now I've looked at the SM:

AA_CPH2: Pass FET for VSET out enable (Select between VSET and VSUS for ramp up portion.) Drives PFET Q604.
AA_CPH1: Ramp up control.
AA_CERS: Ramp up enable (in conjunction with AA_CPH2/AA_CPH1.)
AA_SIU: For buffer board, purpose unclear
AA_SEL: For buffer board, purpose unclear (odd/even select perhaps? or just a chip select?)
AA_CMH: SUS high FET. (Not AA_CEH.)
AA_CML2: Interlock for CMH. Prevents A board enabling both HIGH and LOW fets simultaneously, even if software fails. (Uses a couple of resistors and diodes; not much chance of failure there!)
AA_CSH: ERC high FET.
AA_CSL: ERC low FET.
AA_CML: SUS low FET.
AA_CIS: SUS combine(???) Shorts LOW and HIGH drive together. Not sure of purpose.
AA_UHZ: Protection feedback (SEPA PROTECT, and IC920 which appears to monitor the 16V floating rail.)
AA_CEL: INIT-F enable.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Which manual are you looking at? Not the P50G10?

No P-FET Q604, CPH2 or INIT-F in this that I can see. P50G20/25 would be more what this SC is.

It's a P50V20A

[tom66]

Re: Panasonic sc tnpa5081 rebuild

I'm looking at G10, yes. The G20 probably dropped INIT-F (lower black level), but the rest of the signals are there.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Most are the same, CPH2 and INIT-F dropped.

The Q604 P-FET was the giveaway as that's the FET in the G10 SC fried, SOS7 post

[tom66]

Re: Panasonic sc tnpa5081 rebuild

Now for me to get a 65" VT20 and put it on the living room wall. Will pay up to £50 for any one faulty! If you don't mind asking how much did you buy the three you've fixed for?

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

3 boards or TVs? I only have the one TV, got that for $100 AUD(14 month old), talked my brother-in-law into buying the same dead, got that for $80. Fixed that with a 3 board swap. One SC is that one ( the SOB i just got going) The other was a very new SJ which I blew on the above ( check the damn buffers first), and one was a DOA board I managed to keep from the UK.

And my original SC I threw out during a move frustrated because I could not find all the parts at the time. Boy how I wish I still had it and the 42" 2009 model SC. Even just for scavanging.

I had a flick through UK Ebay, does not look like there's many bargains?

[tom66]

Re: Panasonic sc tnpa5081 rebuild

Oh... Three boards fixed then. Nice, more boards the better. Are you going to sell these boards?

eBay mostly has jokers asking £200 for a cracked screen X50 Panasonic (720p, 2012 model) or other earlier models. Plenty of G20/VT20, G30, etc. But all cracked screens and all for silly money, they never sell them and they re-list them hundreds of times. Only rarely does one with an actual repairable fault pop up. I've grabbed two PZ80s off there. Dead-easy fixes for 1080p screens, but I want a newer, shinier model...

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

I should but this last one is a bit rough now, I would not be happy selling it even though it works but to somone who just grabs it and installs as is it would be ok but for TV shop Tech if they had a look, a little untidy on some of the smaller SMD stuff, pads and board showing signs of heat stress from continually replacing the same parts over and over.

Mind you if you were a DIY and your FHD panny went and $100 for a board, cheaper than a callout.

I'd be happy selling one, I want at least 2 spared for this set and the brother's. Got 2 full buffer sets just in case too.

I put some posts up locally to see if anyone had some dead boards, no joy.

I'd actually love to sell it as an exchange, would not make any real money out of it but I actually enjoy fixing at this level so that would be nice if I could get more stuff to play with but having a TV to test in helps a lot as does having at least one working board to compare.

It'll be interesting to see how long before it does a SC again. I reckon an A-board could be on the cards down the track. I don't need the latest Tv, 2009,2010 models I have I'm quite happy with.

[ted_ge]

Re: Panasonic sc tnpa5081 rebuild

I have the 46" version.
Replaced shorted:
q16421, q16422, q16423
q16402
d16865
q16661
After jumped the sc50 (with removed SU and SD buffers) and turned on
q16661 shorted again (with a bang!)
Do you have suggestions as to why?
Thank you for your time

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

At a glance you've only replaced the blown IGBTs. I trust you have the manual and schematics to follow.

q16421, DG402RP

q16422, DG402RP

q16423, ? is this fitted to your board? normally only 54" and above

q16402, DG502LW

Q16403, Was this short as well? Normally they both go.

d16865 ?? Is that Q16885 2SK3065?

q16661 RJP63F3A

You'll have to recheck all IGBTs again. you may find Q16621,622 could be short.

Check 15V in resistance, P5V in resistance. Check the two 5V regs resistance on Vin , Vout best out of cct if suspect as I had one IC16771 was open cct on Vout.

Hell this is gonna take me forever to try and explain/list.

This is the list of what it took tio get my last board going.

If your board made a loud pop, zap and flash of light between q661 and sc20 you should check all these. pay particular attention to the inverter and nand cct. if the inverter ic773 is not working I suspect that's what blows Q661. Ic691 is the other. the whole cct may need replacing around those items. If the small 5v reg that feeds the inverter is dead, then IC773 will not be operating and q661 will short again.

If you have not read this thread from start to finish, you should there enough clues and info if you write down some notes. I've even circled the 32 odd parts i had to replace on the board in a drawing.

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
IC16792 NJM2406F IC 1 NJM2406F
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

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Just realised you quoted D16865 not Q, still can't find that one though?


Inverter cct , nand cct , FET driver ic521