Panasonic Viera TH-P42S10A SOS 5 Blinks

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

Thanks I was curious if writing a 9 like a P was normal but i guess it would be if someone is doing them every few seconds as they leave the production floor.

It measured fine when i tested it for 209 with the SC still out last time but I didn't check after the repair went back in. Next time around I will verify the important voltages with the SC back in before trying to test with movies etc.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

After removing the blown q401,402,421,422,661 and d865 - many of the other things that tested bad in circuit are ok after all. Notably, 402 blew this time and 401 did not. Last time it was the other way around.
Will post details of found problems later but looks like mostly just the same ones have gone again.

Thinking I must have missed something on the SC, something that allowed it to run for 90 mins before carking it again..
Also still haven't found anything with holes blown in it etc that would explain the loud pop when it happened, which kinda worries me.

Looking at the fet drive circuit as a possible and also have seen the kits that have many of these parts in them- and have found most of it looking ok with a multimeter but this bit stands out:

PC461, the dual opto-isolator right before the 2 inverters on the fet driver circuit - is reading both directions between leads 3-4 on diode test which does not seem right.
Pins 1-2 read only in the forward direction so it's double odd that 3-4 would be any different, although the inputs are hooked up slightly different on the 2 looking at the schematic I still can't see why 3-4 should do this.

In the THP-42S10A schematic(sorry thought i already included this earlier - attached at bottom of this post) - page 72, you can see the fet driver circuit and PC16461 with its internal led's on pins 1-2 and 3-4 with pin layouts 1An-2Ka and 3Ka-4An.

Diode check between leads(pos,neg):
1-2 1.51
2-1 oL

4-3 1.51
3-4 1.02

<Questions>
Does this seem normal or not given the way things are wired?
Is this fet driver circuit likely area that could have an intermittent problem but still function for 90 mins?
Also a question for Tom and tw especially but all answers welcome - what would you be doing from here if this was on your benches?
Oh and just to confirm, if the little rise in voltage from removing c-boards is enough to suspect a panel or c-board even though it can still display a good image or would you look elsewhere now?
</Questions>

I'm starting to look more at this tnpa5081 rebuild thread for clues more than the original 7 blink thread I linked earlier, although that was super helpful getting me to here.
Will go over some other components mentioned here in next few hours too.

https://www.badcaps.net/forum/showth...2&pp=40&page=6

Thanks for taking time to read. It's difficult/impossible to be both detailed and short.

[tw2005]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

I'm 4000k from home so not much I can check out and I only have the TNPA5081 boards to maybe see what the optos do when probed although they won't be the same part?

IGBTs do make a pop without blowing apart. That's what I found.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

Did you have to go to the shop or something? sorry, N.T joke. had to.
All good - thanks for staying tuned in the meantime and hope you enjoy your trip. Where are you visiting? Do they have broken tv's there?

The 5081 mostly just seems to have a similar arrangement, part numbers are different but at a guess i would say functions very much the same with different ratings etc. not sure about the opto but i will try to verify and look deeper before wasting your time, but thanks though! Hopefully i/we can solve it without you needing to take your stuff apart and probe it on my account.

The component #s on the boards on both models are very much similar, the 5v reg and fet driver ic designations for example i think are ic771 and 501,521 on both the 5081 and this 4829AD.
Location - 5081 part - 4829 part:

IC501,521 - M81737 - M81707
Q401,402 - DG502LW/2PG011 on both
Q421,422 - DG402RP - GT30G123
Q661 - RJP63F3A - RJP6065

And i'm sure there is more but I've only just scratched the surface of the comparison. Seeing some of the high's and lows you went through getting there is also heading the same way so far, hopefully i can achieve the same end result despite being severely handicapped in the skills department.

Good to know about the igbt's "popping" too thanks. Since it was on for a fair while I was just past the time of being alert for pops etc and had let my guard down so the pop scared the flying trucks out of me momentarily. Don't want to jinx myself again but hopefully that's all it was. ..touch wood touch wood!
..whew, close.

[tw2005]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

Did you have to go to the shop or something? sorry, N.T joke. had to.
All good - thanks for staying tuned in the meantime and hope you enjoy your trip. Where are you visiting? Do they have broken tv's there?

The 5081 mostly just seems to have a similar arrangement, part numbers are different but at a guess i would say functions very much the same with different ratings etc. not sure about the opto but i will try to verify and look deeper before wasting your time, but thanks though! Hopefully i/we can solve it without you needing to take your stuff apart and probe it on my account.

The component #s on the boards on both models are very much similar, the 5v reg and fet driver ic designations for example i think are ic771 and 501,521 on both the 5081 and this 4829AD.
Location - 5081 part - 4829 part:

IC501,521 - M81737 - M81707
Q401,402 - DG502LW/2PG011 on both
Q421,422 - DG402RP - GT30G123
Q661 - RJP63F3A - RJP6065

And i'm sure there is more but I've only just scratched the surface of the comparison. Seeing some of the high's and lows you went through getting there is also heading the same way so far, hopefully i can achieve the same end result despite being severely handicapped in the skills department.

Good to know about the igbt's "popping" too thanks. Since it was on for a fair while I was just past the time of being alert for pops etc and had let my guard down so the pop scared the flying trucks out of me momentarily. Don't want to jinx myself again but hopefully that's all it was. ..touch wood touch wood!
..whew, close.

Where did the parts come from? For something to work and then fail after that amount of time makes me suspicious.

I think that's happened recently to someone else? Chinese fakes, real possiblity too.

I really would not know where to go with this one but can get expensive pretty quick.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

Probably the answer you were expecting here - igbt's were from utsource.

I'm happy with them though, good service. I did manage to break the thin lead extensions for the middle pin on 2 of the 30g123s but my fault really. They are still usable once new extensions are attached but luckily for me only 1 of the 2 has blown each time so I effectively had 2 more of them than i needed anyway and just put the broken ones aside.
And got the bourns ultra-fast diodes for D865 from element14 in the end.

It's also always possible my work installing things was dodgy too but i did take the time to redo my joints i wasn't happy with after flipping the board over and seeing they hadn't flowed right through etc.

Still have a some spares that could put in and just cross my fingers again but looking at all the extra bits in the igbt driver circuit that seem to often go bad makes me think there is a reason this one keeps popping sos 5 instead of 7 too.

Haven't nailed it down but all my gut feelings are telling me there is going to be something that explains both how it could have run and displayed a picture for a while before letting go - and also why it gets 5 blinks instead of 7.
I've had similar thoughts about bad parts, but am still leaning more towards a component overlooked.
My experience with oseas suppliers has always been ok too. I don't expect much and usually end up happy. + things can often be shipped to my door from across the world for less than a package from element14 in sydney cost's to get to melb.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

I really would not know where to go with this one but can get expensive pretty quick.

I would surely have to be more likely to destroy it before that happens!
Here's my new plan:

Work dangit!

Really though I don't have any plans of going nuts and have very little $ invested in it. I got it for the cost of a beer and fuel getting it home pretty much, and the parts I've damaged so far have been <$15. If I can keep to numbers like that it's hard to go wrong really for a project that might possibly end with a working 1080 panny.

Pretty amazing tv. It's already kept me entertained for at least 12 hours despite not turning on for more than 2! ..my old one couldn't do that.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

Minor udate-
PC461 is not it - atleast not on the input side, the output transistors in it are still untested but we know they worked for atleast 90 mins.

So that theory can be dismissed and your stuff is safe from probing for another day sir! (again, thanks though!)

Your suggestion that it could be just dud/fake/igbt failure may well be correct.

PC461 tested normally once the 390ohm resistor on pin 3 was removed- so the reading was coming via another path and not backwards through the ir diode.
From what i could find it's an NEC 9817A-2 opto-coupler so probably top quality to begin with.


Struggling to think of components that can function temporarily when failed.

Caps are all rubycon and nobody ever seems to mention problems with them that I've seen so far - I can't test them properly anyway but they could be one of few things that fit the description of components able to function for a while when bad? Even Rubycon are still going to have a failure rate after all.

Most other components looks like they would be Go/No Go fails and would not have allowed it to run 90min so I'm not coming up with much!

Now really fighting the urge to just try again with more parts and put a house fan across the board while testing.
Maybe hook a temp probe up to the hottest igbt i can find of these main 5 usual suspects and be ready to shut it down manually if things are getting too hot for my liking.

- I just want to test everything I(or anyone else!) can think of before putting in my last parts on hand in and crossing my fingers again. Ideas welcome and will be entertained no matter how unlikely!

Another failure from here means weeks waiting for parts at best. Seeing it display the image was a great thing though, for that to happen 99% of this thing must surely be ok and I suspect persistance will pay off in the end if I can stick with it. Thanks to you guys for sticking with me learning and helping me through it too

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

I have now researched many hours on this thing and checked everything that's been suggested here and in other threads, compared parts to those listed in repair kits etc and keep coming up with nothing.

The closest i found to another component out of tolerance was 2 identical 5%(3.75) 75 ohm resistors, reading 72ohms and 72.35. For reference they were R504 and R523.

Have checked:
All other heatsinked parts checking ok, no shorts, diodes ok.
IC771 and nearby
IC773 and nearby
IC521,501 and nearby
Q701 and nearby
and many more I can't think of right now.

So I'm out of ideas other than those already mentioned and have started cleaning up the board ready for another go.
Fingers crossed!

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

Update: Bummer #2!

Just switched on after replacing the same components as first time and this time got a fairly quiet crackle and pop and some magic smoke as soon as the switch went to on.

Now shows 2 blinks

Not sure why this would have happened, I'm sure there's plenty of reasons.

After a quick search 2 blinks is apparently 15v sos.

With SC disconnected:
6 blinks and SS led ok, p15v at p25 pin 1 rises to approx 15.8v, p5v at p25 pin 6 4.99v.

Looking for the source of the smoke and noises, D619 is fairly burnt and reading open both directions. Have only checked briefly so far.

Not sure where to go from here but will check the schematic around D619, pull the SC again and go from there.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

D619 test's ok after all. Still looks like it got hot but not to melting point, just charred.

The good news is D865 tests ok this time.
Board still not out, time to do that.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

SC out -
Q401 blown, 402 survived
D865 ok
Q661 ok

Probably more to come, still poking around. Any pointers or ideas welcome and appreciated. Seems even more unusual now.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

I removed Q401, Q402 and Q661 to confirm the above ^

~ The Blinks:
The most common info i can find on 2 blinks is a failed mc201 or mc301 daughter board ic where a ceramic cap or ic can often fail.
This 42s10a however does not even have that daughter board ic on the P board. There is a similar one on the SC board itself, IC791. It has heat shrink covering it though so i cannot see if it has the TEA1611 etc without cutting that off.

Since i heard and smelled the released magic smoke myself I am quite sure there was a short still present when i attempted to power up.
I should have been watching the boards at the time but wasn't, so not sure where it came from. It was an immediate failure when the set tried to bring up the voltages before the relay clicked off again and went straight into 2 blinks.

Not sure why the sos 2 this time but suspect it will be because of something else I overlooked on the 15v circuit shorting and forcing it into this state rather than a more normal 2 blink problem with the IC/capacitor that happened by itself over time.


~ The Curious diode test:
D401,D402,Q401,Q402 in circuit showed shorted again so I removed Q401,Q402 and found Q401 shorted collector-emitter.
Q402 seems ok and still charges and opens/closes as expected.
So D401 and 402 look ok with the bad igbt removed but there is still one little big quirk to them I didn't like and would like to hear what you think!

When testing in diode mode on a dmm the forward reading seems normal but when reversed there is a momentary read. It's only very short and reads about 2.xxxv when first connected before increasing over 3v and going oL. All happens very quickly, less than half a second.
If the probes are left the same way around and it is retested again it will just read oL in reverse direction like it should.
If the probes are switched around to forward direction, and then back to reversed again it will momentarily read as above before going open again. Can be repeated every time and seems odd.

Is it worth removing the D401,402 diodes and testing them out of circuit or is this normal given the circuit they're in?

I'm going to continue feeling my way through the dark and see what else I can find anyway. Fairly sure there is still more failed bits to be found

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

I think I'm onto somethings. Not sure exactly what though! hah.. (long, details below)

First main thing is IC 771(5v reg) resistance:
Positive > negative-
pin 2 to pin 1- 35.5 ohm
pin 2 to pin 3- 129 ohm
pin 1 to pin 3- 163 ohm

Negative > positive-
pin 2 to pin 1- 35.5 ohm
pin 2 to pin 3- 128 ohm
pin 1 to pin 3- 162 ohm

Not sure if the regulator itself is the cause of these low readings but seems suspect. Still checking things before removing anything from the board.

And this is possibly the more important thing?:

IC501 fet driver IC, M81707FP -
VCC(pin11) to Gnd(Pin15)
128ohm
129ohm

IC521 fet driver IC, M81707FP -
3.56kohm
4.09kohm

So 501 looks to have a problem. Which totally makes sense when looking at the schematic it drives Q401 which I am having issues with blowing.
**Although importantly right now Q401, 402 and 661 are not in place on my board. So they could be what would normally make the difference to these readings, I'm not sure.

Here is where i could really use some assistance.

I'm not sure if what I am seeing here is the switching effects of the associated transistors/igbts or the fet driver IC itself, or even the transistor output of PC461.
Would love if anyone could confirm the test below or even just take a peek at the schematic and tell me what's causing the readings to be this way.

--
Repeatable behaviour on dmm resistance setting:
Negative probe stays on IC521 pin 11(VCC)
Positive probe alternating between pin 12(HIN), 14(LIN) and pin 9,10,13,15 or 16(Gnd, You can pick one. I used 15)

-
Negative probe to pin 11(VCC) and leave it there the whole time-
Touch positive probe to pin 15 and hold for a second. Reading increases to approx 3.5kohm.
Now touch pin 12 or 14 with the positive probe and hold for a second.
Then move positive probe back to pin 15, reading is 4-500ohm.

To switch between the 2 states you can simply lift the positive probe and retouch it to gnd, this should get the high 3.5kohm reading. Then touch the positive probe to either pin 12 or 14(HIN or LIN) and back to ground and it should be switched to the lower resistance state again.
-

With leads reversed - positive to pin 11 and negative to 12,14,15 readings take a second to stabilize then, in any order, read approx:
4.09k to pin 15
8.9k to pin 14
8.9k to pin 12
--

I did all this on my IC521 which is looking ok compared to the other one.
When trying the same thing on IC501, I get no switching effect at all but this could well just be because I have Q401 and 402 removed from the board right now and Q421,422 are still in place.

Not sure what component/s are being tested in this process since it is using resistance mode and not diode, but it seems like it might be a useful component side test for others in future whether it is the igbts or otherwise.

I'll continue my learning experience and blog it here in the meantime but would always love to hear some other thoughts.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

Update: I jumped the gun calling Q661(RJP6065) ok earlier. It is shorted source-drain and NOT ok, not switching.
The last 2 Q661's were shorted across all 3 pins so this one a bit different fooled me at first. The rest was accurate though and 401 is toast, 402 still operational.
Those 3 are all I removed so far, so seems on the right track.

The whole area around IC771 and the IC501 fet driver seems suspect including the 2 HA inverters IC464 and IC465 which both show 35.5ohms between VCC and gnd pins - just like the IC771 regulator does between gnd and vout.

There are 2 330ohm resistors presumably for pulling the HA inverter input pins high when there is no input, and both measure way off.
R414 measures 157.5ohm and R415 measures 56.5ohm.
At a guess i would say the resistors will be ok out of circuit and something else is influencing the readings.
It looks to me on the schematic like this can really only be either the HA inverters or PC461 that would throw off the reading and allow another path that is not actually going through the resistor at all. But, who knows. For now it's just notes and I will remove components as I get closer to being sure they are bad.

So seems like a good start to round 3.. but still no real explanation for why it's gone to 2 blinks and shorted on power-up this time compared to the first attempt.
In any case I'm out of RJP6065's to put in Q661 so will have to wait until I have a more complete parts list of other things that are bad and order some more bits.
I have been looking out for another complete sc board or salvage tv in the meantime but no luck yet. Besides I would like to try and get this one working as a project anyway, even though it is getting less practical to try and repair.

[tw2005]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

IC771 feeds the inverters so you would expect the same resistance. 5V at 35.5 ohms would mean a current draw of 140mA. To my knowledge that regulator is rated 100mA.

Does seem like something is bad there. probably going to have to remove the FET driver, reg and inverters to check it all. I'm expecting the FET driver to be bad but I'd be tempted to just replace all those.

With D619 being toasty, i'd replace it but how is the P-FET , Q604?

With Q661, the cct is very different to what i fixed. Anything shorted around it like Q677, Q668, D673, D674?

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

Hey glad to see you back - Hope the holiday to broken panny paradise island went well. Possibly only you and tom would think of that as a great place for a vacation though

Just a quick answer to your query for now sorry, I might post some more details later if they're needed.

As soon as I can I will start removing bits in the ic501,ic771 area. Probably start with the reg and inverters since those pullup resistor readings for the inverters seem off and the reg is almost as good as shorted compared to the 2 others(ic724,725) on the board that are identical chips. I don't have any decent rework gear so taking on the smd ics right now means fumbling around in a tight space with irons. I'm thinking about trying to get a controlled hot air solution before trying the fet driver ic, even if it's a cheapo ebay dealy. I can just see myself damaging leads or pads trying with an iron - especially if it ends up being ok and has to to be cleaned up and go back on again later.

D619 - I realize now all the diodes on the board with the same markings as 619 have similar poorly printed stripe and text on them that I initially thought had burned away from 619. My lighting is/was bad too and I suspect that just made it look glossy and burned in places but was just my eyes playing tricks because no soot or anything came off.
So I think it could be ok after all too. Might try to replace it just to be safe but honestly now I think I just misread things at first again sorry so it's probably nothing.

D673 and 674 - 0.442 forward - Just checked in circuit in parallel but I'd say ok.
^They are showing the same momentary reading in reverse as the curious diodes i mentioned a couple of posts back though which I would feel better knowing a more definite reason for if you have any thoughts on it.
From what i'm seeing its got to be a nearby cap charging-discharging and causing that oddity so not tooo worried about it. I think the thing with the leads being moved around changing the readings compared to just leaving them in the same locations is the giveaway. It charges once and stays that way until discharged by probing something else. Then its ready to charge and show the weird reading again. That's my theory anyway. I'm curious what you make of the switching behavior i mentioned earlier at ic521 too.

Q677 and 688 seem ok, not shorted at least and there is voltage drops that seem normal to me. Sorry I'm being a bit lazy this time and should just post the measurements and let you judge when things are ok or not.
If you ever want readings just let me know, im both happy to do that and grateful for your interest in my project.

I just put the tv itself away yesterday wouldn't you know it, and only kept the sc out but will grab it out and test the other power transistor you mentioned on the p board soon.
If you missed it earlier though on quick test at P25 of power board it did have stable 5v and 15v rose to about 15.8 before it shut down again when the sc wasn't attached. With the sc attached the 15v choked and didn't get above 5. Not sure if that's relevant to q604 or not tho sry I'll have to check later.

[tw2005]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

I never mentioned anything on the P board, only SC I would concentrate on. No , I've got no idea on FET drivers except if Vcc is either open or low ohms I'd treat it suspect. That 128ohms reading sounds familar to a bad driver I had.

As far as removeing them, if you flood all the pins on both sides with solder and have 2 irons, it is possible to lift it that way . No force though or good chance pads will be destroyed.

[DoubleDratt88]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

I never mentioned anything on the P board, only SC I would concentrate on

Oops don't know how I missed that. Was tired I guess?
After reading i looked quickly in the schematic and the only q604 i could find was on the p board - didn't see the obvious q604 right next to the diode until now sorry.

The Q604 on the SC board, looks fine to me :P
The internal diode between source and drain on it tests good and gate is insulated. no low ohm readings.

Thanks for the soldering tips, I've tried flooding pins a couple of times before with mixed results(lifted pads) but am still very new to this stuff and keep thinking of this tv as something precious I don't want to damage now that i have seen it can work, briefly..
Got to remind myself this is a project tv and is nothing to lose and a perfect chance to practice these things on though! That is why i brought it home in the first place really.

Truth is this board already has some minor damage around pads etc from my tinkering too and will never be of use or sold to anyone other than myself anyway- so I don't mind if it looks a bit rough at the end as long as it works, without being a fire or safety hazard.

[tw2005]

Re: Panasonic Viera TH-P42S10A SOS 5 Blinks

Here's something I forgot I had, literally it's chinese but you don't need to understand it to get the infor on what was replaced.

It's SOS5 for a SC TNPA4844 but I would say cct wise it will be very close.

Talking about replacing

Q16661、Q16422、Q16423、Q16424

Q16404、Q16403、Q16402

Q16701、Q16702、D16865

IC16771、IC16464、IC16465、IC16773


This is how google translated it. Not perfect but you get the idea.


Information provided by: Beijing Gao Yong ICT - Zhang Xianxu Application frequency: high □ medium □ rarely □ ■ Low
Subject Matter: Power protection, indicator light flashes 5 times
Model: TH-P42G10C (SC board TNPA4844AD)
[Symptom]
Power protection, indicator light flashes 5 times
[Analysis and thinking]
Because it is a separate SC board repair, five times a P plate display protection embodied in the SC board should have Omo
Burned plot case, VSUS there exists a short circuit, causing the P plate VSUS output short circuit protection, so the lights flash five times.
[Repair process]
1, with VSUS outlet ends of the resistance multimeter is 0Ω, SC board VSUS load has proved short-circuit.
2, the general SC board shorts should be power tube breakdown, not a single power tube breakdown. Measure each power on the road
Tube defects found seven power tube breakdown are Q16661, Q16422, Q16423, Q16424
And Q16404, Q16403, Q16402.
3, remove the damaged device, further examination related load circuit, found Q16701, Q16702, D16865,
IC16771, IC16464, IC16465, IC16773 also short-circuit breakdown.
[Solution]
All 14 components to replace more than a single voltage to the SC board for VSUS found VDA, VSCN, VSNS, VSET
Normal, normal boot-on experiments, end repair.
[Maintenance Experience]
This SC board breakdown parts more carefully if you can not find the slightest omission, power will be once again a large area burned.