whole new repair / learning world... plasma! Yikes!

[tom66]

Re: whole new repair / learning world... plasma! Yikes!

MID is across the two blue caps on the right of this image.
https://www.badcaps.net/forum/attach...6&d=1524904441

It's generally 80-120VDC, or half Vsus +/- 10%.

The green light should glow on the board if VMID is good.

If VMID is low then there is a good chance that your sustain output is not, uh, sustaining.

A scope is helpful at this point.

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

I haven't made any further progress in identifying where the failure is.
The sets flashes a 6 code at shutdown. This is with everything connected. Prior to shutdown, there is P15v and P5v at the sc board.

The first item in the "check list" of possible causes is
"an increase or reduction of the Energy Recovery Circuit output (MID)"... not sure what or where that is on the SC board. Its may be that circuit itself or the circuit, SOS driver, that has an issue.

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

Disconnected everything including powering going to the A board to see if it perhaps needed to some form of "reset" (non-power) to clear any SOS activity.

Connected things back up. Got a screen flash with power on and then a flashing code of 6. :-( I am starting suspect my soldering effort maybe although maybe the 30F131s aren't all working properly.

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

So I decided to use the 30f131's this time around. Replaced all four IBGT's plus some of the 7.5 gate resistors. Recheck every 3 legged component, no shorts.

Placed the SC50 short on and powered up. Got the 8 flashes again.... good.

I think I may have made a mistake at this point. I removed the sc50 short and plugged in the sc20 cable.... BUT I FORGOT to clamp down the three interconnection "spring connectors" going from the SC board to the SD/SU boards ... :-(((

When I powered up in this "mode", I got a brief screen flash and then the set flashed an error. Powered off quickly, and plugged in the clamp down connectors, tried the set again and now the set is in error. :-( Check for shorts, nothing appears to be shorted on the sc board. So thought I would try disconnecting the SC2 connector going from the SC board to the power board. Expecting 7 flash but am getting 8 still... :-( Measured the open circuit voltage on the SC2 cable / power board... 100 plus DC but that's after a few second as I don't have enough hands to power up and monitor the pins at start up.

It would appear that I have taken some form of control out on the SC board by not connecting it up fully before powering up the whole system. Any ideas?

Further: I got an extra hand, and check the open circuit voltage going to the SC board at power on and it is 200v DC so the system is attempting to start without the SC board attached.

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

so inspection (with meter) shows the failure took out the four fgd4536's, two blew their tops while two had a ground to emitter short. Along with those, two feed resistors on the q402,q403 show high resistance (normal 7.5) so those need to be replaced also. Checks of all remaining "three legged" semis don't any shorts.

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

So.... I went ahead and plugged things up. Hit the power button and eventually saw a screen and was able to see a disc playing on the input that I had setup. JOY! :-)

BUT, the joy was fleeting.... :-( I notice a bit some "smoke" coming up from the sc board... :-( quickly turned the set off and went to get my thermal imager just in case I could may be see what's (its a low res one so odds were slim). Anyways, turned it back on and within 30-40 second, I got the big POP again. :-( This time, q402 and q423 both blew their bodies. I haven't checked if anything else went, hope not. So two steps forward, 1.5 steps back. At least, now I know that perhaps the problem is only with the sc board (and the suspect / fake components) as I did hear and see a portion of the screen (on the side of the table). Hopefully, my practice removing fgd will make the operation easier. Maybe my soldering ain't so good... :-)

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

question for you... can I run / test the system with the sc50 shorted and the sc20 plugged back in for a short test without causing card problems / failures to see if the blink code goes away?

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

continuing the slow march.... slowly re-reading the TS pdf, I see that SOS change for 2011 models was done which output 8 blinks IF the SC20 is disconnected. Sounds like that is why I got the 8 blinks during the SC50 short test.

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

well... small progress.

I did the "short sc50 connector" test... no pops but the led flashed out 8 blinks which I have told is a problem with the ss board. :-( I haven't even look at that side of the set as my focus was on the SC, SU, SD boards.

This could take a bit more reading and looking. :-)

A quick read of the 2011 plasma troubleshooting manual indicates this ... "8 Blinks condition is also caused when the connections between the panel’s flex-cables and the sustain board are broken or the connector are not properly seated." as one possible cause.
Hope the dumpster wasn't too tough on the panel... :-)

I guess the one question is... is the "8 flashes" valid with the SC board having a SC50 short on it and no SU / SD boards connected?

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

well... I guess I am attacking this faster than I thought. :-)

Anyways, got all the parts and soldered them in place. I replaced the 3 "previous fgd4536" (only one was blown) but thought I would try my luck with some others that came in. Time will tell.

This time instead of totally plugging in the sc board, I will try the "short sc50 connector test" with the board "isolated" from any other boards but well screwed done and see if things survived. At least this way, I can hopefully find out if my soldering and replacement components are any good.... especially since I have no history for the panel itself (recycle bin).

Any last words???

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

sorry for the long process / delay on this "work". Delivery from the "far east" has been some what "unpredictable" along with a mistake (selected a 1w 1 ohm as opposed to a 1 ohm 1/4 watt... 1w is too big for the footprint).

Anyways, I hope to get re-acquainted with the effort again. As you know, my first attempt ended up taking out a few components (7.5 ohm, 1 ohm, one fdg4536, plus a couple of other fet ... numbers are back in the thread).

I know there is lots of discussion around fake fgd4536's (30f131). I was looking at ways to at least hope for a better outcome this time around.... so I was trying the "simple diode" test on some of the fgd4536 that I have received to see if I get some sort of predictable results. Of course, the test doesn't fully test them but surely there must be "reasonable predictable" outcome. So positive lead on the middle contact (collector), negative on the emitter ("right" contact), not reading (diode check mode). touching the gate with red lead ("left" contact) momentarily to charge gate, move back to the center contact, get a reading.
My question is the predictability (and "reasonableness") of the reading. On the "first attempt" units, I am seeing .9v while on the "post ordered" units, I am seeing 2.6v which appears to be quite a difference. The question is: does this mean anything in terms of whether these fgd's are good or "fake" or otherwise?

I am not attacking this work too fast as post summer activities (house, vehicle, trailer) are taking precedence but hope to slowly get it moving again. Thanks for any further comments on this.

[Moreno83]

Re: whole new repair / learning world... plasma! Yikes!

I have to say , i did not replace the R6015ANX on the powersupply. It does not read short but i got a small beep from 1 of them.

So i will order the parts as i need them in the future and replace the 2.

[Moreno83]

Re: whole new repair / learning world... plasma! Yikes!

Thanks for the info but i replaced that 1 with a dg302 from a ss board. Same for the one under the other heatsink.

When i turn the tv on it shuts down , no green led on the sc board. Not even a little light...
The fet on the left side of the board , 63G4 is short for a little while and then short is gone.

Challenge!

[WildPuppy]

Re: whole new repair / learning world... plasma! Yikes!

I know I'm not fit to give advice, especially to you but I like to share my experiences with others just in case they did not read my topic:
In my case, after using fake parts and blowing them up, they took out Q451 under the radiator which was measuring OK before the fakes. This caused my 7 blinks to go to 6 blinks. On my board it was a DG302 but you may find a RJP there depending on the manufacture year of the board. Just replace it with a FDG and it should resurrect to live once more.
Also don't forget to check the driver circuitry for all the FETs ans a broken driver can take them out again. In my case the gate resistors and diodes survived both the original blow and the fake parts one.

[Moreno83]

Re: whole new repair / learning world... plasma! Yikes!

So i bought a 42VT30 today. Owner said a repair shop tried to repair it but failed.....

I opened it up and they also used fake parts. So easy to see. the 30F13 and RJP30H2A don't even have a small hole ( marking ). Isopropanol on the logo and logo almost vanished. The logo should get back very clear! If it vanishes or is vague it is fake.

So this SC board gave a big bang 2 times. First with original fault and later with fake parts. Replaced all fets and diodes with original parts but the tv won't boot , it goes to 6 blinks.
So there are more parts dead on the board.

Conclusion , after using fake parts it is hard to repair the board. Will put the tv away and when i feel like it i will repair the board replacing the small diodes , resistors....

Hope you got more succes with your board because this 1 is damaged to much.

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

I was doing general checks while waiting on parts along with following the 60st30 repair thread. I just noticed the during my one attempt at powering that one of the feed resistors of the one blown 4536 is also "broke"... :-( will probably just use a regular resistor instead of an smd as the one track was originally damaged during the FET removal.

Checks of the other boards (SC,SD) show no shorts, so I am hoping that basically if and when I get the SU board up and running, things will be happy.

[freakaftr8]

Re: whole new repair / learning world... plasma! Yikes!

Ah my apologies. You are correct. It is 1 ohm. I was looking at a different reference.

[Moreno83]

Re: whole new repair / learning world... plasma! Yikes!

2.2? Mine measures 1 OHM and it is rated as 1RO ?

I got a european board , might be different then american/canadian boards.

[freakaftr8]

Re: whole new repair / learning world... plasma! Yikes!

Should be fine. On that resistor in question yes it is a2.2ohm resistor SmD type. It can use a standars type half watt resistor if you want.

[budwich]

Re: whole new repair / learning world... plasma! Yikes!

I did a check of the diode packs that were replaced and compared to the old. The forward bias voltage on the RFN10 is slightly different. The old is .48v ish while the new is .52v ish. I have a couple other "new"... one reads .48 and while another reads .52. Not sure that would make much difference as the spec indicates .98 max. The rf1501's all (old and new) read .42v.