Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

[ERICSSON89]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

hello everyone.
I'm here to learn and I'm a student. please can anyone tell me about this SC BOARD, SU/SD? and what are they?
any feedback would be nice.

[myfastgti]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Thanks tw, I've ordered new SD board and will report back next 3 days.

[myfastgti]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Finally I got the SD board and to my surprise the new board is shorted too. I've ordered new buffer chips from China and will wait to arrive and try not to rip off the tracks while removing the shorted chip.

[myfastgti]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Hi Guys, wanted to give a quick update. Yesterday I got another SD board from the same seller at no extra charge, installed right away and the TV is alive, never thought I would see this day again.

Just wanted to thank everyone who have helped me in diagnosing the problem especially TW and Alastair for your valuable time and great efforts in sharing the information and troubleshooting guide.

Another TV saved from going into recycle. And TW you're right about not to replace the buffer chips cause they are glued to PCB and I ripped two tacks from my old board.

[CoinCoin88]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Hi guys,
Newcomer here. Domed by the infamous 7 blinks last Tuesday while watching Star Wars. No need to say I was pissed. As a good friend of mine is into video business (more like furnishing complete sets for TV or cinema). I asked him for help. While his tech was at it I rapidly found about the sc (and possible su/sd) defects. Today he told me exactly the same thing, and that he was trying to find a good deal because the complete sc board is around 200 euros. Bummer... (It's a p50gt30).

I took the tv apart at his shop thinking that I'd inspect the board myself, since it's most likely blown mosfets. However my electronic skills are a little rusty.
For now I have only the sc board with me, the rest is at his shop.

My question: can I start troubleshooting the board while it's disconnected from everything else? So far I see a short between the two legs of sc2 and most of the igbt appear shorted (rfn10, rjp30h2a, rfn20, 30f131, daf30a)... That seems to represent a lot of this board, so I'm wondering if I'm doing things right. I'm planning to troubleshoot using sc50 and isolation of su/sad this week end or next Monday, but can I start with the sc board on its own or studying it while disconnected brings nothing?

Thanks for your help!

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Hi guys,
Newcomer here. Domed by the infamous 7 blinks last Tuesday while watching Star Wars. No need to say I was pissed. As a good friend of mine is into video business (more like furnishing complete sets for TV or cinema). I asked him for help. While his tech was at it I rapidly found about the sc (and possible su/sd) defects. Today he told me exactly the same thing, and that he was trying to find a good deal because the complete sc board is around 200 euros. Bummer... (It's a p50gt30).

I took the tv apart at his shop thinking that I'd inspect the board myself, since it's most likely blown mosfets. However my electronic skills are a little rusty.
For now I have only the sc board with me, the rest is at his shop.

My question: can I start troubleshooting the board while it's disconnected from everything else? So far I see a short between the two legs of sc2 and most of the igbt appear shorted (rfn10, rjp30h2a, rfn20, 30f131, daf30a)... That seems to represent a lot of this board, so I'm wondering if I'm doing things right. I'm planning to troubleshoot using sc50 and isolation of su/sad this week end or next Monday, but can I start with the sc board on its own or studying it while disconnected brings nothing?

Thanks for your help!

If SC2 is shorted , don't bother with the SC50 isolation test. what's the point, you've also found shorted components.

Also for info

RFN10, RFN20,DAF30A are diodes and a good chance

the shorted IBTs RJP30H2A, 30F131 may be contributing to them showing short.

There are repair kits although hard to be sure they will cover every part blown.

And test the buffers for shorts, beware of loose screws on the Sc and SS boards and or arcing/poor earth.

[CoinCoin88]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Ok so basically I'm heading in the right direction, at least for now. I'll try to lift the pins of these shorted igbt, and see it it fixes the short in sc2. If it does, I'll just replace them and proved afterwards with isolation tests. Coil your confirm that it's the right approach ?

Thanks for your help, I've read a couple posts on this board and you always seem to come up with valuable intel!!

Edit: to test the buffers, should I refer to this post (https://www.badcaps.net/forum/showpo...0&postcount=15) ? As far as I understand, these measurements are taken on sd/su, not sc (or is it the "next step" after replacing shorted igbts on sc?)

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Ok so basically I'm heading in the right direction, at least for now. I'll try to lift the pins of these shorted igbt, and see it it fixes the short in sc2. If it does, I'll just replace them and proved afterwards with isolation tests. Coil your confirm that it's the right approach ?

Thanks for your help, I've read a couple posts on this board and you always seem to come up with valuable intel!!

Edit: to test the buffers, should I refer to this post (https://www.badcaps.net/forum/showpo...0&postcount=15) ? As far as I understand, these measurements are taken on sd/su, not sc (or is it the "next step" after replacing shorted igbts on sc?)

That chart is for the series before so I'm not 100% if the pinouts are the same. There's a chance there is guide for 2011 models already in this thread. You could as a quick test put the meter in diode mode and put one on the gnd plates and slide the other slowly along the face of the ribbon connectors looking for shorts or get the manual and identify the labels in that chart and compare to the pinout on the Sd/Su boards and do the resistance tests.

I think the guide has an alternate method but I think the first challenge is repairing the SC. might be handy posting up the part number of the SC.

With the legs on those transistors I assume you'll heat the solder and gently lift the lags? Try not to get too much heat into the pads or they'll lift off the board.

[CoinCoin88]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Yep I'll use a blade to life them slightly and see if sc2 is still shorted. I'll check in the 2011 guide if there's a way to test the buffers. First things first, let's see after lifting the shorted igbt legs if sc2 is still shorted.

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

manual from Brazil with good detail for part numbers

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Yep I'll use a blade to life them slightly and see if sc2 is still shorted. I'll check in the 2011 guide if there's a way to test the buffers. First things first, let's see after lifting the shorted igbt legs if sc2 is still shorted.

It's not just a matter of clearing the short at Sc2, you need to go over it entirely and maybe do a fair bit of searching to see if there have been successful repairs here, and also check out the kits for an idea what bit to check.
not going to be able to help much with this board not having repaired or seen one but a few have done S30 boards so the cct will be similar and I'd expect you'll get some input from them if you're patient.

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

this may help a little

[CoinCoin88]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Well i'venlifted one pin for each shorted igbt and i stil see sc2 shorted. This doesn't soundtrack so good...

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Well i'venlifted one pin for each shorted igbt and i stil see sc2 shorted. This doesn't soundtrack so good...

Quite often those IGBTs short across all 3 terminals. You'll need to lift both legs.

If the leg lifted is short to either of the othe 2, you may as well remove the whole thing. keep a note of what was where,

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

What is the board number of the SC? TNPA5335BG? or ?

[CoinCoin88]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

Tnpa5335ag

[CoinCoin88]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

As for lifting both legs, I've been trying for the past hour. Not sure why but solder at pin 3 never melts whereas there's no problem for the first one.

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

As for lifting both legs, I've been trying for the past hour. Not sure why but solder at pin 3 never melts whereas there's no problem for the first one.

what wattage iron? Since they have no heatsinks it's possible the size of the copper land is drawing the heat away? What are the location numbers of the parts?

I guess you've used fresh leaded solder to assist in heat transfer?

I think 40w would be at least what you'd need

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

I bet it's the emitter on the 30F131 that won't heat up. looking at what it's soldered too , massive copper lands, might even need more than 40w. If you don't have the right iron if you keep trying you may damage the board trying too hard.

[tw2005]

Re: Panasonic Plasma TC-P50GT30 7 blinks SC board shorted

This is a kit worth studying, also shows FET driver Ic and pnp/npn dual transistor. that the 2 tiny SMD parts shown. Does have a DAF30 diode so expect that may be short on your board

http://www.ebay.co.uk/itm/PANASONIC-...item232f6e5265