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2015-05-23

Panasonic TX-P50GT30E. Once more the 7 blink disease - TNPA 5335 scan/sustain board fixed cheaply.

When I saw a 7 blink Panasonic GT30 in eBay classifieds (Kleinanzeigen), I acted immediately. I've learned how to fix this standard problem of the 30 series with my 42ST30 and this one was bigger and the better G-type. The S-type is the budget version. The G improves on the S as follows:

  • DLNA
  • SAT receiver
  • USB recording
  • Improved contrast filter
  • Much finer image adjustment options. Two expert modes and a THX mode.
So I picked it up for 200€. A quick measurement revealed the usual. Loose screws and 6 transistors plus 2 diodes shot. This time I found a cheaper repair kit for the TNPA 5335 board from Germany for 40€.

Let's have a look. The next image makes me go wow! Just wow! Panasonic Plasmas are magnificent machines, meticulously built. It's a pleasure to study the attention to detail. If Panasonic just wouldn't have, well, screwed up the screws.




In the 50 inch model, the buffer boards are separated from the sustain boards, which makes maintenance a lot easier. The panel connectors can stay seated. As I reported here, those are not easy to handle.


I examined the screw holes and their contact area. This did not look good. I think we see black traces of sparking here:

The next image shows the damaged semiconductors. It was not as bad as with the 42 inch. No ICs and small signal transistors affected, just the big thingies. Neither had the power supply failed. I think, in this model, the engineers paid more attention to protection circuits.


Here we go again. Pre-heater plate and hot air makes replacing the parts a smooth operation:


The TV started up no problem after the repair.

The 50GT30 is a brilliant TV. The images are stunningly beautiful. The 3D performance is second to none. Crystal clear. It feels like looking through a window into the world. No other TV I've put my hands on comes even close.

The sound is bad, though. A lot is missing in the highs and there is too much fat in the midrange. I don't care much, as I have my stereo to the left and right of the screen.

A TV as gorgeous as Scarlett Johansson :-) Nothing beats a Plasma when it comes to skin tone.


Watching Gravity in 3D is breathtaking:



Plasmas have a natural sharpness, which LCDs just don't seem to achieve without tricks. The plasmas don't have the funny lock-in effect on hair, when suddenly the shimmering, silvery reflections stand out once a person stands still.

Well, I'm afraid my beloved Sony, which is my first TV repair must trade places with my new darling :-)

It still puzzles me that the screws are the reason for the defect. Their material is very soft. The screwdriver wears them out quickly. Maybe they stretch too much. Or the solder they sit on flows and that loosens the screws. This would be a silly engineering mistake. However, some screws are mounted on a solid bracket and those were still sitting tight. So maybe the engineers underestimated the importance of the problem screws.

67 comments:

  1. hi
    Hermann schmidt

    i have panasonic TX-P50ST31B has no power & no bilking red light,I have try all basic tricks change plug fuse try different power point butt still no luck.
    please help me to bring back my dead tv alive.

    thanks

    ReplyDelete
    Replies
    1. On my tv there is a power switch on the front that is basically invisible. I spent hours testing power board components to no avail before I found it.

      Delete
  2. Hi,

    if your TV does not even have a stand-by light it's most likely the power supply. Second candidate is the main board. However, I hope you understand that I cannot offer any remote diagnose here and tell you how to repair your TV. If you are not familiar with electronics, I'd suggest you let someone have a look at it who is sufficiently qualified.

    ReplyDelete
  3. Hi Hermann, Good info pity you don't go in depth to repairing the board with new bits that are at fault, do you think that when rebuilding the board washers behind and spring washers might be an idea to stop it happening again?

    ReplyDelete
  4. Don't you fancy making a Video of changing parts ?

    ReplyDelete
    Replies
    1. I thought about it, but it is just too much work and I don't have the proper equipment for making movies, either.

      Delete
  5. Hi Hermann!
    I'm newbie here.. I have exactly this tv, with 6 blinks... Measured >200V on C631, then changed the two DG302 (Q441 Q442) and their drivers IC502 and 531. Then voltage across C631 dropped to zero.. Then changed other two DGs and drivers IC522 and 551..but nothing changes. All parts taken from a working SS board. Both 15V and 5V are there, and Vsus rises to 204V (that should be ok). After this, still 6 blinks!! Can you give me any help to solve this??
    Thank you so much in advance!

    ReplyDelete
    Replies
    1. Hi,
      I haven't been in the situation where you are on this particular board. Never experienced a 6 blink on the 50 inch model. I see that you have read my 6/7 blink instructions for the 42 inch already. Well, that is all I know about this subject. I can only suggest to do more measurements on the recovery section. It is not impossible that you have damaged some of the tiny parts while soldering. In your case, the recovery L section must be defect somehow.

      Delete
    2. Hi Hermann.
      After having checked all diodes and resistors of recovery section, I changed the IC16562 and the board started to work!!
      But I had a bad surprise: now tv switches on, with green led on, but the sceen remains black. Calling an osd seems that some "falling snow" appear, but barely visible... Do you have any suggestion??

      Delete
    3. Geez,I really don't know. Haven't seen that before. The SC board is still not working perfectly, I guess.

      Delete
    4. One last question: can we exclude completely that it could be the plasma panel itself? I would avoid to purchase a working SC board and have the same result... (I have also changed the a-board, but same result...)

      Delete
    5. A quick update: I've measured Vsus 214V, VAD 65V, Vscn -132V , all measures taken with tester on DCV and the negative probe on the panel metal surface.

      Are there fine or not?

      Delete
    6. The voltages look ok. Can't say anything about the panel. Never saw a failing NeoPlasma panel so far.

      Delete
  6. Hi!

    Thanks alot for your reply. I will do more checks and let you know..

    ReplyDelete
  7. Hi Hermann.
    A short update: you've been right. I have changed the SC board, and tv lighted up again!
    But with a bad surprise: there's one lie of pixels that randomly appears with an average of 66% of the total time. I haven't been able to upload a photo... Could it be a SD board issue or more likely it is a panel problem?

    ReplyDelete
    Replies
    1. Sorry: one line of pixels

      Delete
    2. Again: one horizontal line of pixels, sometimes complete line, sometime only partially...

      Delete
    3. Only the panel can produce partial lines. If a buffer chip was faulty, it should be always the full line. On the other hand: defect buffers can destroy SC boards. Is this your own TV or did you get it for repair? If the lines have not been present before the SC fault, I would suspect that something is bad with a buffer.

      Hard to say, really.

      Delete
    4. I got this for repair. But if it was the buffer that destroyed SC, then it should destroy this one too..Maybe I will try to find a temporary working SD board to make a trial. Do you think it could be useful?

      Delete
    5. It's difficult to say when the history of the TV is not fully known or the owner wasn't very observant or doesn't tell you everything.

      I would also suspect that if a buffer is broken and killed the SC, it most likely would do so with the new SC. Thus, a panel fault is likely and the SC failure may be totally unrelated to it.

      Delete
  8. Hi again Hermann,
    Just posted in your 42" section before noticing this blog which actually is the TV I have (bought cheaply with 8-blink fault). I replaced all the 'standard' components with a repair kit, including Q501/531 and IC501/502. it was challenging to work with these tiny parts. How did you determine that they did not need changing on your SC board?
    Unfortunately, on re-applying power (with the buffer boards isolated and SC 50 jumpered) Q422 exploded, R422 burnt out, Q521exploded and I guess most of the IGBTs have gone again. No idea why, as there was no short of Vsus line before power, and no obvious cause :-(.

    ReplyDelete
  9. I guess your repair kit was garbage. I studied the spare part situation in detail in my blog. I found good sources with reliable parts.

    Once all the large diodes and transistors on the SC board have no shorts anymore and the resistors are ok, it is safe to turn on the device. If it is still not working some driver circuit needs replacing. The 50+ inch models with separated SN and SC boards normally work fine without.

    To answer your question in the 42 post: I always use hot air and a preheater plate.

    ReplyDelete
    Replies
    1. I meant to say separated buffer and SC board instead of a combination of both in an SN board.

      Delete
    2. Thanks Hermann.. I hope you are right, and new parts will fix it. I will re-read your blog on sources.
      I know that you will need to delete this line but for reference I had my parts from what seemed to be an established source with good feedback ratings.
      http://www.mbtvelectronics.co.uk/mbtv-electronics-store/repair-kits/tv-repair-kits/panasonic-tnpa5335-ysus-repair-kit-txp50gt30-txp50st30-txp50vt30-txp50c3e/

      Delete
    3. Nah, I won't delete that link as you don't profit from it. I suggest that you take a strong looking glass or even a microscope and examine the surface of the spares compared to the originals, like I did in one of my posts. This can be revealing.

      Delete
    4. A broken buffer board may also kill the SC board. Test it for shorts in the power supply lines that connect them to the SC. Also, a continuity check against the connectors to the panel is a good test. They all must be equal to each other.

      Delete
  10. Right again Hermann: Unless the encapsulation and collector plates have changed over the years, both types of IGBT are not oem. The 30F131s don't carry the Toshiba logo and the text is not etched. The RJP30H2As have different colector plate, different typeface and different logo in the circular indent.
    See pics at https://photos.app.goo.gl/iehos5tDcYFPRipg1
    I've ordered a bunch of Fairchild FGD4536 certified as original from a UK supplier, and will fit in place of both. As back up have also ordered 20 DG302 from your checked source (ridiculously cheap) but will be a few weeks in transit.
    The 'explosions' ocurred with the buffer boards isolated, although I had anyway checked for a short at C842 before ordering the repair kit.

    ReplyDelete
    Replies
    1. I have seen worse copies. Depending on the batch, they do not have to look exactly identical, I figured. However, I think there are no legit source of 30F131, RJP out there besides Panasonic. With the FGD you will be fine. And don't forget the diodes. Those are easy to replace. My DG302 work totally fine. I am pretty sure that a SC board with only DGs on it will work, too. I hope my supplier hasn't changed his source in the meantime. And I suggest you get yourself a cheap hot air rework station like the obiquitous and dirt cheap 858D.

      Delete
  11. After struggling to remove the first IGBT with an iron I bought an 858D just for this repair... amazing bit of kit for the money. After the explosions there were no shorts on the board, unlike initial failurees, which tends to support a crappy device theory. I am part way through building the test circuit and will measure the characteristics of the survivors.

    ReplyDelete
    Replies
    1. This comment has been removed by the author.

      Delete
  12. FGD4536s just arrived, but despite Fairchild markings I am not convinced... Gate-Emitter threshold is around 1.5volts with full switch on by 1.6v. That seems much too low; believe it should be around 3.3v typ?
    Don't want to clutter your blog, so the results of earlier tests are here:-
    https://drive.google.com/file/d/1of13wVoRc6XcUd_Sn8XzMCGMmg4VWs39/view?usp=sharing
    The only working RJP (No 6) is from those originally fitted at mfr.
    Nos 1-5 are the suspected fakes.

    ReplyDelete
    Replies
    1. This comment has been removed by the author.

      Delete
    2. Progress! The FGD36s did not expire, so now things are improved to 6 blinks. Maybe IC502 again or one of the other ICs (little diode pairs all look Ok by resistance check).

      Delete
    3. Okay, now your recovery L or H section is defect. I described the process of measuring and fixing in a post for the 42 inch. Should be similar. Haven't had that yet in a 50, however yours went through a lot of trouble.

      Delete
  13. Thanks again; I've learnt such a lot from your blogs and from commentary in the Badcaps forum.... but not enough! I think I've been thwarted yet again by fake parts as after finding a bad joint on a gate driver and a duff IC522 I thought I would be in business, but once again at power up all the suspect 4536's blew up and took all the series resistors and a gate driver with them, not to mention probably ICs again. Not being prepared to risk more bad parts I have reluctantly sent the board for repair by someone who has known good components. (Your source dried up the day I looked at the link).
    From your 42" blog I finally figured where the Recovery L and Recovery H (higher and lower?) sections are, but it might be an idea to clarify that somewhere? Question: On this scan panel, with the SU and SD boards isolated, are the IGBTs really still being loaded?
    To help me check the little ICs and gate driver chips I used the linked tables that I put together after finding tw2005's post on Badcaps.
    As ever, feel free to delete any of this babble.

    https://drive.google.com/open?id=1YxBLYO_C0t6yUvkuPLWsoRPvPNKZ-v8n

    ReplyDelete
    Replies
    1. Geez, you just don't have any luck with this one. I cannot answer your question about the isolated SU/SD. For 50+ inch repair I never had to do any fancy things, just two diodes and six FETs.

      Thanks for the measurements table. I think I have found similar instructions somewhere in another document. Can't remember.

      Delete
  14. Update: (please delete or move content as appropriate!)
    The guy has had my SC board for over 3 weeks and is struggling to repair. He's got it working, but with poor image quality and after a couple of minutes the TV he's testing on shuts down again with 7 blinks. Says it's the hardest repair he's had.... I killed it good.
    Can you help with a question again? I have the chance of a defective ST30B which has the same SC panel, but the fault is a 3" wide dark horizontal line across the middle of the screen. A faint live image is still there behind the dark band. Strangely, I can't find any mention of a similar fault on a plasma anywhere, so at a bit of a loss to know whether it may be the panel, a connector completely out, or a board/drive issue. I mainly hope it can't be caused by the SC board, as this could be my backup source. Any ideas?

    ReplyDelete
    Replies
    1. Uhh, hands off this one! Semi-transparent bars are most likely panel failures.

      Delete
    2. Well, the saga continues (good job my life doesn't depend on these boards!). The original board I killed with fake parts is finally on its way back after testing the skill and patience of the repairer. He replaced the voltage source ICs 784 and 786 (after all the usual stuff still didn't cure it).
      While all that was going on I picked up an ST30 with 7-blink failure and (like you have found) only the 'usual'IGBTs were shorted due to loose screws (blackened earth points). I replaced them with the DG302s that arrived from Shenzhen WinWin and sure enough the TV came to life. Moved the board to the GT and it looks (looked) marvellous.
      However, after a 5-hour continuous run, POP! and 7 blinks. Two of the DG302s had gone short, and also taken out Q622, a 30F131!
      After replacing the two duds and Q621,622,and 623 with DG302s I have 6 blinks and need to borrow a fast peak-hold DMM to see if it's recovery high or low.
      Unfortunately I think we have fakes again, though maybe goodish ones. They don't look the same as pics of the pukka Panasonic ones, and the legs are all shapes. They also came just bunged loose in a little poly bag rather than proper antistatic strip package.
      UTsource may be the next try: their pic looks OK!

      Delete
    3. Oh dear! Now I am glad I had stocked up a large number of the critical parts a while ago.
      The packaging China style tends to be sloppy. That does not necessarily mean the parts are junk. My DG302 came in a simple plastic bag.

      And don't count too much on the pics! They may be old or "borrowed".

      Delete
  15. Time to say thank you! Your blog encouraged me to fix this device. I was succsessful. I have one last question left. The sc board is doing sounds. Not very loud i need to stand behind the tv to hear it and i opened it to locate it. Its my first plasmatv and i dont know if it is normal.

    ReplyDelete
  16. Congrats! The buzzing is normal. All Plasmas do that.

    ReplyDelete
  17. Here's a really great document: may not be able to leave the comment due to the copyright, though hardly an issue now they are out of the market.
    https://1drv.ms/b/s!AhyAtuUSxECNjQx4Jmmifq6QhPcS

    ReplyDelete
    Replies
    1. This is really cool!! A collection of a number of different documents I have plus more.

      Delete
  18. Hello, Hermann and everyone.
    Thanks for your posts and the patience with us.
    I have a problem with a TX-P42ST30E; that I don't see nowhere, in your blog, and in other ones. I switch on the TV; and it works with no problem. Right. It runs fine a while (may be 5 seconds, or 5 minutes, or 5 hours, or 5 days...). But, suddenly, it goes off (no red LED), and, immediately, it switchs on; and it runs fine. No red LED blinks.
    And, in addition, when the TV is in Stand-by mode (red LED ON, fixed), occasionally it sounds one relay, that I am not capable to find in the schematic.
    I changed the Main board, with no results. I changed the Power supply board (not new one, but the guy that he sended me it told me that it was checked (it was sended from one company from UK, through eBay)), with result of 7 blinks. !!!!!!!! For me, weird!!!!! With the original board it never happens.
    I have checked the YSUS card visually, the IGBTs, the drives, the GND screws and their welds. I do not see obscured components; no blackish remains on the tin in the screws.
    Honestly, I expected that the problem was in the P board, but…………
    If you can guide me, I would appreciate it.
    Thank you very much.
    Jose Iglesias.

    ReplyDelete
    Replies
    1. Hi Jose,

      I did fix a ST30. https://alpengeist-tvrepair.blogspot.com/2015/04/panasonic-tx-p42st30e-tnpa5330-board.html
      However your problem seems to be something else.

      I think your replacement power supply is dead. Check the fuse and the MOSFETs that I described in my post.

      As for the other phenomenons you've described, I have no real idea. I suspect the power supply, but you might have to make one good from two broken ones.

      Delete
    2. This comment has been removed by the author.

      Delete
  19. Hello, Hermann.

    Thanks. I'll do it. At this moment, I am going to find another replacement P board; because I think the problem is in the P board still. Because it is an intermittent issue, it is not easy to check.

    One intermittent problem, or two simultaneous problems is the worst nigthmare for the thecnicians. I am an industrial electronic thecnician (laser cutting machines), and, 10 years ago, I had in one machine three simultaneous issues, that they were not related to each other. Three days for find them!!!! Evidently, only at the end of the job one know that there were three problems, and not related to each other.

    Thank you, and regards.

    ReplyDelete
  20. Hello again Hermann,
    Glad you are enjoying time away from TVs during this lovely summer!
    Having fixed the ST, GT and VT and with the soldering station still set up, I thought I would return to the now spare YSUS board that was badly damaged due to fake components at the beginning of my project. This board eventually came to life but then became intermittently bad, and is now bad all the time. All IC's and driver pairs check out as OK and all other components read the same resistances as on a good board, so I'm stumped and likely just to abandon it again. However, I will post a link to a video clip of its performance just in case you have any clues!??

    https://photos.app.goo.gl/Tr3graPs1R8VtZFZA

    Kind Regards
    Steve

    ReplyDelete
    Replies
    1. Hi Steve,

      that's a funky YSUS! I have not yet seen such before. What's interesting is that the Y-buffer bands are sharply separated from each other and that they vary in brightness. The pixels as such are at the rigth place, so basically, the Y-scan is right on time. Yet there is someting wrong with the charge. The flickering is too quick to tell, but it looks to me as if the buffers are not stable. Sometimes they black out, sometimes they don't. So, my suspicion is that their voltage is soft. Vscan comes to mind. I have not yet investigated this part of the Ysus boards, so I am not sure what I am talking about :-)

      Delete
    2. The last components to be changed (which started the board working but with this problem) were actually the Vscan & Vad generator ICs 784 & 786.
      Voltages are spot-on; Vad at 200 and Vscan at 147 relative to Vfg.
      Energy recovery is also happy at 113v, so no easy clues to what's amiss I'm afraid.

      Delete
  21. Hola buenas tarde leyendo todos los comentarios me pareció interesante.. bueno si alguien me puede orientar tengo un Panasonic TX p50gt30e y me cuentan que al encenderlo escucharon un sonido y ahora da 7 parpadeos rojos.. l destaparlo me di cuenta de un transistor había explotado el rjp30h2a.. mi duda es tengo que cambiarlo todos o solo el que ha explotado gracias...

    ReplyDelete
  22. Hallo Hermann,
    ich hoffe du schaust hier noch ab und zu rein.
    Mein TX P50GT30E hat mir bis jetzt gute Dienste geleistet. Seit einigen Wochen hat er einen dunklen horizontalen Streifen bekommen und seit heute geht nichts mehr mit 7x blinken. Ich dachte zuerst der Streifen kommt von einem schlecht verbundenen Flachbandkabel, da es sich besserte mit ein wenig Druck auf den Rahmen.
    Kennst du noch eine Bezugsquelle für die Reparatur?
    Vielen Dank!

    ReplyDelete
    Replies
    1. Klar schau ich hier rein, schon weil ich den Spam immer löschen muss :-D
      Dein Fall ist anders als der Standard. Der Fehler scheint mir vom Panel auszugehen. Wenn du nicht erwähnt hättest, dass Druck auf den Rahmen was verändert, dann hätte ich auf einen defekten Buffer getippt. Ob das jetzt Kollateralschäden verursacht hat, kann ich nicht einschätzen. Ob das überhaupt reparabel ist, kann ich schwer sagen. Wenn es das Panel ist, dann sicher nicht.

      Delete
    2. Danke für die Info.
      Ich hatte damals gesucht, was diesen Streifen verursacht und wie das zu beheben ist. Dann stieß ich auf diese Flachbandkabel und habe einfach mal versucht ein wenig Druck auf den Rahmen oder die Rückwand auszuüben.
      Jetzt ist es auf jeden fall das 7x Blinken Problem.
      Woher bekommt man denn die Transistoren/Mosfets heute?
      Danke!

      Delete
    3. Ich kenne leider keine zuverlässige Quelle mehr.

      Delete
    4. Hi,
      ich hatte nun Teile auf Aliexpress gekauft und sie getauscht.
      TV funktioniert wieder, allerdings hat er nun ein starkes Einbrennen/Nachleuchten - eigentlich unbrauchbar.
      Kann das an billigen Chips liegen?
      Danke!

      Delete
    5. Ja, ziemlich sicher. Es gibt auf Ali keine guten Teile mehr.

      Delete
  23. Hello,
    I just replaced faulty components (only RJP30H2A and 30F131, diodes are good) on my TNPA5335 board and TV starts normally.
    So far so good, but 2 min later I noticed that all of 3xRJP30H2A starts smoking. I think because of overheating.

    Is it possible this LOT of RJP30H2A to have manufacturing defect?

    ReplyDelete
    Replies
    1. It's possible. I think that there are no legit parts on the market anymore besides the ones that are packaged in Panasonic plastic bags.

      Delete
    2. Thank you for this advise.
      All fake transistors get very hot and picture was bad. May be because of slow switching of fake elements.

      I bought original Panasonic parts and for now all is good.
      Thank you once again!!

      Delete
  24. Hi again Hermann! Long time since I posted anything.. Have now fixed perhaps 8 or 9 50" 2011 models for various people but nothing in the last 2 years until now. Got a VT working with FGD4536's but after a few hours it exploded and I found that I had foolishly allowed three of my fake batch to be fitted. As usual, this caused a lot of consequential failures that have taken a good long while to find and replace. The SC now 'runs up' with all voltages correct but the dreaded 6-blink recovery fail still. Mid voltage only gets to 8v max. The Recovery Low circuit seems fine though: The buffer IC and driver pair pass all checks (weren't blown) and I even took out the DG302's that passed diode checks and confirmed that they switch correctly under load on the little tester. Every other component in the circuit tests OK and all values measured around that part of the circuit compare exactly with a known good board. Does this perhaps mean that the buffer IC is not getting the correct input signal? Probably beyond my powers if not!
    Incidentally, why have a lot of contributors (self included) become 'Unknown'?

    p.s. Have recently changed my main TV to an LG OLED ....finally seem worth having.

    ReplyDelete
  25. Ah... my name returns after filling in the new form.
    Have you come across instances where these IC's pass diode checks but can still be faulty? Maybe I should replace IC522 and Q551 anyway...

    ReplyDelete
    Replies
    1. Hey Steve,

      I really can't guess what's wrong with the device. Basically, it is the chain control-ic -> buffer transistor -> resistor -> IGBT. Any piece there can break. The extra trouble is the uncertainty whether the replacement parts are good or not.

      Delete
  26. Good morning please am having problems with my Panasonic side which I need the transistors and the diodes numbers so I can replace them

    ReplyDelete

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