Panasonic sc tnpa5081 rebuild

[Alastair E]

Re: Panasonic sc tnpa5081 rebuild

Q661....

It Always comes back to that one bloody transistor it seems....

Its strung between the -VAD and the VF-Ground (VFG)
-- We know VFG aint really a proper ground--Its pulsing up to VSUS with each sustain cycle, and the Buffer-chips ride on this, so VFG is their Local Ground--sorta.

--Q661 Appears to be the Set/Reset Ramp generator, supplied by the -VAD on the bottom end (E) and VSUS at the top. (C)

VAD isnt a supply that can (I dont think) source Much in the way of high current looking at its transformer, so the current that destroys Q661 in fault-conditions therefore--Must be coming from VSUS, that grounds through the VAD Transformer and the rec diode--as Q661 is on when it shouldn't be..
--The Transistor, RJP63F4A Q661 I know from experience can handle some considerable current, as Ive used one in a supply for a washer motor--Has No trouble doing a full 7Kg load and 1600 spin! Whatever is killing it on TNPA5081 is Pretty High Power stuff...

Ive tried with partial success to prevent major blow-ups using a 150W bulb in the VSUS to the board,--but still Q661 can die, probably due to the charge in the caps on VSUS Supply.

So--Idea, Use a Bulb in series with Q661 Collector...

It would need to be Two 240V lamps--As -VAD is around what?--170V? and VSUS over 200...
On the Next Blow-Up (As thats all I'm doing lately!) I'm gonna rig up two 15W 240V pygmy-bulbs in series with Q661 Collector...

I dunno--Might prevent Huge blow-ups and tell us if the board is still buggered,-- Or maybe I'm just talking bollox....
--It May make things a Whole lot Worse--Who knows--Gotta be tried!

[dolivas27]

Re: Panasonic sc tnpa5081 rebuild

Aye--The curse of the electronics industry--The NDA! Those plus the Patent have probably hampered technology development more than anything else over the last 200 years! Personally, I dont agree with patents, NDA's and all that crap...

Ive ordered 20 of the little suckers--should keep me OK for a while, just need to order more DG502/DG402 etc now, but will experiment with RJP56F4A and RJP43F4A for now...

100% agree on the patents, NDA's

Do you know how I would check the SC board after repaired with a scope before the SU,SD boards were reconnected?

I want to make sure I have the

+5v
VSCAN-F
Vfo
VHIZ

The thing I noticed in the block diagram is when in bypass (SC50 Installed) Q16660, IC16792, IC16793 are not being tested so maybe I have one of these bad?

What really sucks is I don't have a known good set of SU/SD boards so for all I know I am fighting all this just for a bad SU/SD board.

I found this quote in the 2009 handbook so this explains what the SC50 Loop is doing.

Beginning last year (2008), the plasma TV
are designed to shutdown if either the SU or
SD board is disconnected.
Disconnecting either board causes the unit
to shutdown and the power LED to blink 7
times.

Unplugging any of the connectors
SC41/SU41, SU11/SD11, and
SC42/SD42, opens the interlocked
connection between VF_GND and CHA on
the SC board. This floats point “CHA”
triggering the SOS7 detect circuit. This
outputs a high to the A board through
connector SC20 triggering shutdown.

[Alastair E]

Re: Panasonic sc tnpa5081 rebuild

Ive been looking at that block-diagram, and trying to figure out just Why--In Every Case these boards go bad, Q661 Kacks it....

Wondering if bunging a Bulb in series with its collector on a board during test will save it and maybe prevent further failures--Even if the board is still bad...
I think however, there's around 500V across this part during normal operation....

Guess I'll need Two Bulbs....

[Alastair E]

Re: Panasonic sc tnpa5081 rebuild

Aye--The curse of the electronics industry--The NDA! Those plus the Patent have probably hampered technology development more than anything else over the last 200 years! Personally, I dont agree with patents, NDA's and all that crap...

Ive ordered 20 of the little suckers--should keep me OK for a while, just need to order more DG502/DG402 etc now, but will experiment with RJP56F4A and RJP43F4A for now...

[dolivas27]

Re: Panasonic sc tnpa5081 rebuild

For reference--The Transoptor, PC461 Optocoupler is a Renesas part, PS9856-2

I cant find datasheet for it but does seem readily available from Chinese suppliers inc UT etc...
Ive ordered from the supplier recommended earlier in this thread via Ali-Express, we see how that turns out...

You will never find a spec sheet for that part and I would suggest you order a good supply of them.

Here's the quote I received from the Engineer I was working with at Renesas now California Eastern Laboratories

Hi Dean,

Sorry to keep you waiting. Since the product was designed for Panasonic Japan, Renesas cannot disclose the specification under the NDA with their customer. So, please check with Panasonic-Japan for the info.

Regards,

Van N. Tran
Staff Applications Engineer
California Eastern Laboratories

[Alastair E]

Re: Panasonic sc tnpa5081 rebuild

For reference--The Transoptor, PC461 Optocoupler is a Renesas part, PS9856-2

I cant find datasheet for it but does seem readily available from Chinese suppliers inc UT etc...
Ive ordered from the supplier recommended earlier in this thread via Ali-Express, we see how that turns out...

[Alastair E]

Re: Panasonic sc tnpa5081 rebuild

SCNR_PRO on pin 8 of the SC42 connector means?............

TBH--Not a clue!

Seems you have gone in much greater depth than I currently have! Trouble is, with the way I'm set up I need to get stuff through and out the door--so the more weird stuff--Like These--gets regularly held up and put aside....

Thanks for that link--I'll get some ordered. There's not much point in me going much further on any of these boards--Till Ive got those, apart from resistance-tests...

[dolivas27]

Re: Panasonic sc tnpa5081 rebuild

If you take a look at this picture you will see what the SC50 bypass is doing it's providing the VFG to CHA

I don't know why but I have a strange feeling that the SU11/SD11 ribbon cable was not seated right.

If I am right that would mean Q16471 was not turned on and SCNR_PRO would have been shorted to VFG causing it to go BANG. Well that a theory I have probably full of shit but trying to figure it out.

One other thing MAKE SURE you look at PC603 Opto. On the board I am working on before testing the 4th repair I went over everything on the board with a fine tooth comb....... and I found that pin 4 had a poor solder joint as in it was not even solder to the board! There was solder there but the pin was loose maybe from working on it and flexing the board but make sure you check it.

I checked all the Opto's on the board and re-soldered most of them just to be safe.

Hope this helps.

[dolivas27]

Re: Panasonic sc tnpa5081 rebuild

Anyone found a source for the Transoptor, PC461, B3PBE0000054.......?

Ive two SC/SN boards, reading low on the VAD+5V line, removing these I get the expected 5.6-6K readings....
--One board was the TNPA5066 that I had rebuilt--and was working where I touched the VSUS supply lead--And killed it again. Bloody cruddy single-supply pin arc....

Another is the TNPA5105 that I did a repair on expecting it to work--only lasted 5 seconds before that too went bang....

The TNPA5105 from a 50" that was used as a test-mule for the above board, Thats gone too....

That one--a TNPA5105 with lots buggered on--Including Q660 strangely....

Not having much luck--Except the readings of these Dual Op-Amp, MOSFET O/P Opto's are all weird on all of 'em.....

I ordered from this seller on AliExpress and was very please with the product.

I also ordered some from parts simple here is the US and they were the same exact part I received from China and to top it off I ordered them at the same time and the ones from China arrived a week before the US ones.

http://www.aliexpress.com/item/Free-...334315932.html

I have had the same problems they were not bad on the first failure but on 2 & 3 they were and on the 4th they survived.

Quick question for you do you know what the SCNR_PRO on pin 8 of the SC42 connector means?

I really do not think the SU / SD boards I have are bad but don't know for sure.

Once I have the board repaired again I am going to measure some voltages to see if the 5V is there and I might get a scope to check the other outputs.

Once that is done I am going to isolate the SU board first and see how it goes. That is the only board that has a strange reading the TPSU17 (5V_F) reads 8.56M

[Alastair E]

Re: Panasonic sc tnpa5081 rebuild

Anyone found a source for the Transoptor, PC461, B3PBE0000054.......?

Ive two SC/SN boards, reading low on the VAD+5V line, removing these I get the expected 5.6-6K readings....
--One board was the TNPA5066 that I had rebuilt--and was working where I touched the VSUS supply lead--And killed it again. Bloody cruddy single-supply pin arc....

Another is the TNPA5105 that I did a repair on expecting it to work--only lasted 5 seconds before that too went bang....

The TNPA5105 from a 50" that was used as a test-mule for the above board, Thats gone too....

That one--a TNPA5105 with lots buggered on--Including Q660 strangely....

Not having much luck--Except the readings of these Dual Op-Amp, MOSFET O/P Opto's are all weird on all of 'em.....

[dolivas27]

Re: Panasonic sc tnpa5081 rebuild

Thanks guys for the input.

Pin 9 on the SC41 connector should be VFG & SD41 connector should be CHA.

The SU board provides the connection to the SD board this connection is through the SU11/SD11 connectors on pin 20

If my assumptions are correct this is what the SC50 connector does when shorted and the SU & SD boards are isolated from the system.

This would explain why the connector needs to be installed during isolation of one or both of the boards.

After testing all the pins on the SU11/SD11 connectors it looks like
Pins 1, 4, 7, 10, and 13 all connect to VFG screw terminals on the corresponding boards.

Pin 20 (Connector SU11) is providing the VFG to the SD board. If you remove the SU11/SD11 cable you will not see the VFG on pin 9 of SC42 connector.

The CHA provides the VFG to the D16475 diode which drive the base of Q16471. Do I have this right?

Now the million dollar question if the SU board was not providing this VFG to the SD board would that cause the SC board to blowup?

Does anyone know what the SCNR_PRO on pin 8 of the SC42 connector means? I can see it's a return signal from the SD board but I don't know what SCNR_PRO is?

[Alastair E]

Re: Panasonic sc tnpa5081 rebuild

Worth looking at and cleaning, replacing or hard-wiring completely--The VSUS Supply Cable from the PSU to the SC and SN boards....

Ive had a failure caused by a Very Slightly dodgy plug/socket arrangement causing a spike on the VSUS...
I'm pretty convinced that these plugs/sockets/cables have caused many of the SC failures we have seen in these sets....

[dolivas27]

Re: Panasonic sc tnpa5081 rebuild

what if you followed suggestions from tom66 or alastair e and has some incandescent bulbs in series on the vsus line for the SC and hope it saves blowing it up? I've never done it but they both swear by it as the power is taken by the globes and not the board if it shorts??

I will try that at the next go around need to order a few parts should have them by the end of the week.

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

what if you followed suggestions from tom66 or alastair e and has some incandescent bulbs in series on the vsus line for the SC and hope it saves blowing it up? I've never done it but they both swear by it as the power is taken by the globes and not the board if it shorts??

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Ya I am going to give it another go but I don't know how many more after that.

Do you know how the SC50 bypass works with just one board removed?

not too sure. I tried that on a 2011 and got nowhere. on it's own it passed, when i tried just sd it failed 7 blink even though it said it would work. Then I put the bad board in minus the shorted buffer and it worked.

so for the 2010 models i simply have not tried it.

[dolivas27]

Re: Panasonic sc tnpa5081 rebuild

You're right. You need a good samaritan to help out here and maybe offer their TV as a test bed. If the SC passed a SC50 bypass test and was then put n a TV and it blew up the SC then I think that would be conclusive.

Is it worth going on? I have no answers for you and the resistances sound normal.

If another model TV surfaces like a 50" then you could potentially continue at least with a different panel and buffer set.

50g20,g25,gt25, or even a S2 you should be able to shoehorn the board for a test at least.

Ya I am going to give it another go but I don't know how many more after that.

Do you know how the SC50 bypass works with just one board removed?

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Ok thanks I just need to find another TV to test my work after it's repaired again.

At this point I think the SU board might be bad. If the SU board was bad but not shorted would that still blowup the SC board?

If I isolate the SU board but leave the SD board connected with the SC50 jumper installed would the TV still power up with just the bottom half of the TV working?

Trying to figure this out when the SC50 jumper is installed and the SU / SD boards are removed from the circuit.

We're sending VFG from Pin9 of the SC41 (TO SC-BOARD) connector to Pin9 of the SC42 (TO SD-BOARD) connector on the SC board.

When the SU / SD boards are reconnected as normal with the SC50 jumper removed. The VFG is now sent through the small ribbon cable connecting the SU / SD boards (Connector SU11 / SD11)

If for some reason the small ribbon cable was not seated right would that case the SU board to Fail?

If one of the boards (SU / SD) were bad but not shorted would the SC board fail / blowup?

Just trying to get my head around why it works fine with the SC50 jumper installed but not with the SU /SD boards installed. I have looked the panel over with a bright flashlight and do not see any cracks or short marks on the screen.

The reason I am starting to think that the SU board might be bad is that Pin6 (5V_F) ohms out to 8.72M on the new board I purchased and 8.29M on the original board.

The new boards were purchased off of eBay so they could be bad or good.

Do you think I should purchase another set of boards and measure them?

The SD board is very close to what the resistance reading should be.

Well let me know what you think……..
Thanks

You're right. You need a good samaritan to help out here and maybe offer their TV as a test bed. If the SC passed a SC50 bypass test and was then put n a TV and it blew up the SC then I think that would be conclusive.

Is it worth going on? I have no answers for you and the resistances sound normal.

If another model TV surfaces like a 50" then you could potentially continue at least with a different panel and buffer set.

50g20,g25,gt25, or even a S2 you should be able to shoehorn the board for a test at least.

[Alastair E]

Re: Panasonic sc tnpa5081 rebuild

Put a 150W Bulb in series with the VSUS to the 5081 next time.

May not prevent a failure--but may prevent Lots of stuff blowing--in an instant...
--Check out my minor saga with a baulky-board on the thread TNPA5066 rebuild 42c2b
Bulb saved the day....

[dolivas27]

Re: Panasonic sc tnpa5081 rebuild

I don't think for a quick test it would be an issue plugging the 54 in a smaller screen, going the other way though it would be under rated but I'd expect it to work, just would not do it for long.

Ok thanks I just need to find another TV to test my work after it's repaired again.

At this point I think the SU board might be bad. If the SU board was bad but not shorted would that still blowup the SC board?

If I isolate the SU board but leave the SD board connected with the SC50 jumper installed would the TV still power up with just the bottom half of the TV working?

Trying to figure this out when the SC50 jumper is installed and the SU / SD boards are removed from the circuit.

We’re sending VFG from Pin9 of the SC41 (TO SC-BOARD) connector to Pin9 of the SC42 (TO SD-BOARD) connector on the SC board.

When the SU / SD boards are reconnected as normal with the SC50 jumper removed. The VFG is now sent through the small ribbon cable connecting the SU / SD boards (Connector SU11 / SD11)

If for some reason the small ribbon cable was not seated right would that case the SU board to Fail?

If one of the boards (SU / SD) were bad but not shorted would the SC board fail / blowup?

Just trying to get my head around why it works fine with the SC50 jumper installed but not with the SU /SD boards installed. I have looked the panel over with a bright flashlight and do not see any cracks or short marks on the screen.

The reason I am starting to think that the SU board might be bad is that Pin6 (5V_F) ohms out to 8.72M on the new board I purchased and 8.29M on the original board.

The new boards were purchased off of eBay so they could be bad or good.

Do you think I should purchase another set of boards and measure them?

The SD board is very close to what the resistance reading should be.

Well let me know what you think……..
Thanks

[tw2005]

Re: Panasonic sc tnpa5081 rebuild

Well guy's really bummed out right now....

I received all the new parts rebuilt the board again went over everything and it looks perfect.

Installed it in the TV power it up with the SU/SD disconnected and it powers up perfect no errors.

Recheck the SU/SD they look good to me with no shorts. Reconnect the SU/SD remove the jumper power the TV on and BANG all kinds of shit blown again!

I don't know what to think at this point either the SU/SD are bad or the screen is defective.

Going to take a few days off from this I need to order a few more parts then I will have at it one more time.

If I pickup another TV that uses the same SC board can I install this board it a 42" / 50" in the same series? This is out of a 54" just to prove out that the board is good?

I picked this up cheap and it should be here next week I know it's the wrong board version but it will give me something to look at to compare a few things.
http://www.ebay.com/itm/TNPA5081-/30...vip=true&rt=nc

Thanks for all the help......

I don't think for a quick test it would be an issue plugging the 54 in a smaller screen, going the other way though it would be under rated but I'd expect it to work, just would not do it for long.