Re: TC-P55GT30, 8 Blinks, Poor Picture Quality
Guess you have the fault-finding document, but just in case:-
These 5 conditions can cause 8 blinks..
1.
Abnormality of the Sustain drive circuit.
2.
Open or loose connection between the SS board and FPCs from the panel.
3.
When SS53, SS54 or SS56 are disconnected.
4.
[B]When SC20 is disconnected.[/B]
5.
Wrong diagnostic by the A board
To determine if the 8 blinks is caused by the A board, SS board, or the Panel:...
foxyUK
Member
Last Activity: 02-01-2022, 04:35 PM
Joined: 01-03-2018
Location: Rhyl
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Re: Panasonic TX-P42ST30B the 'ol 6 Blinks
Okay.... got there.
It was the other DG302, Q551. Strange devices these! In circuit the resistances were not deeply suspect, and diode check gave fluctuating results, which was odd. Tested properly out of circuit, the device was fully conducting with low voltage and hardly conducting at all at 5-6v, pretty much the inverse of normal operation.Leave a comment:
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Re: Panasonic TX-P42ST30B the 'ol 6 Blinks
Unfortunately I don't have access to a 'scope, and I only tinker with these series 30 plasmas because I learned how to fix the SC on one for my own use and they seem to crop up regularly in my local area, so have done four 50" models. The 42" seems to be a bit more of a nuisance!
I realise that my dmm with Min-Max is not fast enough to catch all that is going on with MID properly. I'll change the other DG302 just in case, and maybe Q531 that measures OK with diode check but may be different with higher voltages?Leave a comment:
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Panasonic TX-P42ST30B the 'ol 6 Blinks
Got rid of 7 blinks by changing the usual 6 IGBTs and the FETs & Fuse on the P board that always seem to go on the 42's.
Changed IC502 which was dead, but not Q531 which diode-checks OK.
First look at the 6-blinks, found Q441 suspect (not short, but lowish resistance) so tried an FGD4536. Mid voltage 190v... no good. Salvaged a DG302 from a spare SS board and still 6 blinks, but Mid is now 85 volts (a bit low) until the point where shutdown is initiated, and then it instantly shoots up to around 200v....[B]is that normal?[/B] (Given that at the moment I don't know why it is shutting... -
Re: whole new repair / learning world... plasma! Yikes!
If it's similar to the UK ST and above models, there is access through the software service mode to 'high' and 'low' Vsus settings, and a recommendation to check which is appropriate after a board change. You can also find panel hours via the same route.
For whatever silly reason, the key presses to enter service mode, at least in the UK, are not those shown in the manual! (they take you to the self-check screen instead).
See this great post by Tom66 for service menu usage (copy it!!!) and also hours usage....Last edited by foxyUK; 11-15-2018, 10:41 AM.Leave a comment:
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Re: TX-P50G20B with 8 blinks
The error code flashes of the red standby led should occur as soon as you switch the TV on (after a brief green led).
Here's a link to the troubleshooting guide:-
[url]https://1drv.ms/b/s!AhyAtuUSxECNmxEeAu7684zjsybQ[/url]Re: TX-P50G20B with 8 blinks<br /> ...84zjsybQ[/url]Leave a comment:
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Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted
I was wondering whether a 300w limiter on the mains input would help to protect Vsus shorts (on the 42" sets it seems to blow the P board FETs and slow-blow fuse when the SC IGBT's go)... but then found your tip here, which sounds more promising. Guess you have to cut a Vsus lead and fix afterwards?
Do the sets work normally with that small voltage drop, if no shorts?...Leave a comment:
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Re: whole new repair / learning world... plasma! Yikes!
Part of the discussion towards the end of the item linked below notes that the different versions are 'tuned' to the specifics of the display panel, so I guess you would at least need to establish if the replacement board came from a 50" TV. Looks to be difficult to find specifics.
[url]https://alpengeist-tvrepair.blogspot.com/2017/03/replacement-of-discontinued-panasonic.html[/url]Re: whole new repair / learning worl...ussion towards...Leave a comment:
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Re: whole new repair / learning world... plasma! Yikes!
one more thought... DG302s seem to go 'bad' without going short, so can be harder to spot. The checks on Q531 don't include pins 1-4, but a resistance check here or across R532 should be 47k. If it's low, the DGs could be bad. It's a regular fail on the 42" but I haven't seen it on my 50" repairs....
Leave a comment:
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Re: Panasonic TX-P50ST30B Bad Picture after SC repair
Seem to have fixed it
For reasons unknown the 'repair man who failed' had also unsoldered, checked, and refitted Q661 IGBT in the Vad circuit. His iron was not hot enough (again) and the drain was sitting on but not soldered to the board. Reflowing this seems to have done the job. Perhaps strange though that Vad voltage was spot-on. I don't have a scope, but if there's a signal here as well as a voltage, that would explain.
Thanks everyone for your contributions.Leave a comment:
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Re: whole new repair / learning world... plasma! Yikes!
6 Blinks is indeed consistent with the energy recovery mid voltage being out of limits. It should be very steady, only fluctuating by a few volts. Typical level is around 115v.
So... you need to check again IC502, IC522, Q531, Q551, Q451&2, D461&2, Q581, Q441&2, D481&2. (those little Ic's and driver transistor pairs being the favourites for incidental damage after an explosive event).
If you have changed any of them, check for pins that haven't actually been soldered to the board...Leave a comment:
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Re: Panasonic TX-P50ST30B Bad Picture after SC repair
Not tried putting it back yet.... will 'diode test' a few more components first. I really doubt that it's interconnects: I've never seen reports of those hefty plugs 41, 42 & 46 causing issues. The troubled card (from my other post) is the first one I tried to repair. Fake parts in the repair kit caused other parts to blow after 6 hours of good running and it then needed a whole raft of replacements and still wouldn't run again. Eventually I sent it to a more experienced repairer who changed even more parts before getting...Last edited by foxyUK; 10-24-2018, 03:24 PM.Leave a comment:
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Re: Y sustain keeps blowing FETs ? (LG)
I know nothing about LG plasmas, but reinforce Angelos' comment: on Panasonics it's almost always fake components that cause repaired boards to fail. These 'copy' power components work after a fashion but can't reliably handle the high power...sometimes for seconds, sometimes for tens of hours only. You need to track down 100% genuine parts or known good equivalents.Leave a comment:
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Re: whole new repair / learning world... plasma! Yikes!
Yes, the guide is wrong. For IC724 pin 1 should be negative for the voltage shown. Reads about 1.5v for pin 1 +. Also, the centre pin 2 is not connected to the heatsink (the actual pin 2).
[and yes, there should be 3x 30F131 and 3x RJP30H2A on the SS board]...Last edited by foxyUK; 10-23-2018, 06:04 PM.Leave a comment:
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Re: Panasonic TX-P50ST30B Bad Picture after SC repair
Further update:
Jeepers, these things can be frustrating! It's definitely just the SC board.
I swapped it out with the one mentioned in this post:-
[url]https://www.badcaps.net/forum/showthread.php?t=71298[/url]
....which had a very similar fault condition and wasn't working. In this set, at the minute, it's working perfectly.
I can't trust it to continue, as something must be intermittent. This board also has FGD4536 in the three 30F131 positions.Re: Panasonic TX-P50ST30B Bad PictureLeave a comment:
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Re: Panasonic TX-P50ST30B Bad Picture after SC repair
Minor update: All ground connections very sound. Vsus is spot-on correct at 215v.
A quick prod suggests that the DG302s are OK, and as my mid-point energy recovery voltage is fine at 115v, wouldn't that fail if the DG302 circuits were bad?
I'll have to try another SC in the TV.
Interestingly, I couldn't get into the service manu until I found Tom66's post which suggests using Vol- and 000. Strange that all the manuals/guides say it should be Vol- and iii. (which brought up the self-test). Changing Vsus to high...Leave a comment:
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Re: Panasonic TX-P50ST30B Bad Picture after SC repair
Hi Moreno,
Thanks for responding: I value your input which has helped me before in reading through these threads.
Whoever diagnosed the SC for the previous owner clipped some of the IGBT leads and clumsily unsoldered one (dragging a pad off due to inadequate heat) but the components are original. I've used FGD4536 in all IGBT positions which has been fine on 2 previous boards (same batch). However, I do have a spare SS board that could liberate some parts if your other suggestions don't yield anything...Leave a comment:
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Re: Panasonic TX-P50ST30B Bad Picture after SC repair
I didn't touch the SU/SD or panel connectors, but the TV is new to me after buying from someone who decided to replace rather than repair. I've fixed 3 of these SC's without issue, but this one has the problem. It had been into a depot for diagnosis, so maybe other things got disturbed there. I will swap in a known good SC from my working TV to be sure (just hate having to undo all those screws to get the back off!)Leave a comment:
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Re: whole new repair / learning world... plasma! Yikes!
Do you have this guide, which describes many of the tests on these SC boards?
In theory it shouldn't be copied or distributed, but I figure Panasonic are probably no longer interested?
[url]https://1drv.ms/b/s!AhyAtuUSxECNmmK-bZWYoxYi-hVu[/url]
Now, can someone help me with my poor picture after an SC repair (see post!)Re: whole new repair / learning worl...y it shouldn'tLeave a comment:
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Re: Panasonic TX-P42G10B SC board failure?
Is the board disconnected at SC2? Have you found the Panasonic troubleshooting guide for your model? (they are all there if you search hard enough).
In general, find the IGBTs on the SC board and check for short circuits between the outside or outside and centre pins. Any short means at least one is dead (they are wired in parallel).Leave a comment:
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