Panasonic Plasma SD, SU Buffer IC repair

[tw2005]

Just starting a thead hopefully where those who like to have a go and share tips , tricks, info etc to consolidate information on Buffer board repairs for the Panasonic PDP.

The scarcity of some parts now forcing us to find other solutions like component repair which I've enjoyed, I'm now about to venture into the challenge of replacing these devices.

I'm sure there's quite a few already doing this and having success so I'l kick this off with a few images of two SU boards awaiting my first ICs to solder in.

I find acetone, and acetone free nail polish remover helps break up the silicone. It's probably best to remove as much of the silicone first, then cut. I get a blade and cut the pins at the case of the IC, then I like to soften up with the acetane a bit more, then run fresh solder in preparation to desolder those fine pins.

I have not tried a Hot Air Station and tweezers yet;

bread packet clip, ice cream sticks, tooth picks to remove and massage that grey silicone away.

Does not take much heat or effort to tear or lift a pad.

On one of these, pin 97 which is needed I've lifted but managed to save it.

This is a link to another thread on these buffer ICs.

https://www.badcaps.net/forum/showth...fer+ic+removal

Thanks to Kilroys for sharing.

Hope to have some happy news when my chips arrive.

[martino]

Re: Panasonic Plasma SD, SU Buffer IC repair

Got the popcorn out aaaaannddddddd......GO!

[Alastair E]

Re: Panasonic Plasma SD, SU Buffer IC repair

Well--Last week I changed two on the same SU board for a 50U30B

I peeled the grey silicone sealer off the pins by finger-nail getting as much off as possible, running my nail along the pins of the chip carefully and avoiding too much pressure at the ends of the rows, its quite easy to bend the first ones in the row.

Then when it was clear I couldn't get any more off, I cut the pins from the chip body with a good sharp Stanley-knife carefully with a shallow angle and as close to the chip body as possible.

Before removing the chip body--which is stuck with silicone to the board, I de-soldered the cut pins by flooding with solder, letting the heat do the work, using no pressure, the cut pins float away from the board pads, a bit of braid cleans them and the excess solder away.

When all are off its pretty easy then to pull the chip body off the board.

Again the fingernail can be used to remove the silicone that was under the chip. scraping In Line with the pads--Not across them. The pads were all cleaned up carefully-- (Watch your iron temp--Pan. print is Delicate, 320 deg Top.) with fresh solder and braid. Not a pad was damaged...

Refitting is then just like any other buffer-chip--Use Lots of Home-Made Flux, then cleaned off after you're sure the pins are all soldered correctly, followed by a coating of your favorite gloop--In my case, Ulti-Meg! On this 50U30B, I added some nice heatsinks to the both buffer-boards, kulled from LG sets, stuck with HY-910 heatsink plaster silicone.

The Grey type silicone is easy to remove. The Black type Panasonic used on later sets--Is Not--Its a much harder plasticy almost hard mastic type stuff...

I dont believe its possible to remove these chips with hot air, the silicone under the chip stuffs up that idea and the extra heat needed to soften the silicone would bugger the pads....

[tw2005]

Re: Panasonic Plasma SD, SU Buffer IC repair

Well--Last week I changed two on the same SU board for a 50U30B

I peeled the grey silicone sealer off the pins by finger-nail getting as much off as possible, running my nail along the pins of the chip carefully and avoiding too much pressure at the ends of the rows, its quite easy to bend the first ones in the row.

Then when it was clear I couldn't get any more off, I cut the pins from the chip body with a good sharp Stanley-knife carefully with a shallow angle and as close to the chip body as possible.

Before removing the chip body--which is stuck with silicone to the board, I de-soldered the cut pins by flooding with solder, letting the heat do the work, using no pressure, the cut pins float away from the board pads, a bit of braid cleans them and the excess solder away.

When all are off its pretty easy then to pull the chip body off the board.

Again the fingernail can be used to remove the silicone that was under the chip. scraping In Line with the pads--Not across them. The pads were all cleaned up carefully-- (Watch your iron temp--Pan. print is Delicate, 320 deg Top.) with fresh solder and braid. Not a pad was damaged...

Refitting is then just like any other buffer-chip--Use Lots of Home-Made Flux, then cleaned off after you're sure the pins are all soldered correctly, followed by a coating of your favorite gloop--In my case, Ulti-Meg! On this 50U30B, I added some nice heatsinks to the both buffer-boards, kulled from LG sets, stuck with HY-910 heatsink plaster silicone.

The Grey type silicone is easy to remove. The Black type Panasonic used on later sets--Is Not--Its a much harder plasticy almost hard mastic type stuff...

I dont believe its possible to remove these chips with hot air, the silicone under the chip stuffs up that idea and the extra heat needed to soften the silicone would bugger the pads....

What would be great would be to see some pictures of your work just to see how you used that ultimeg. I was searching that dow product and no real joy here but found a USA site that had it $20.. no shipping outside USA though

[Alastair E]

Re: Panasonic Plasma SD, SU Buffer IC repair

This is the product I used-
http://www.ebay.co.uk/itm/XRS-GR-120...UAAOSwSdZWgYzS

Makers website-
http://www.aev.co.uk/index.php

I'll see if I can get some pics of the buffer, but it also now has heatsinks but still should be able to see the chip pins.

[tw2005]

Re: Panasonic Plasma SD, SU Buffer IC repair

This is the product I used-
http://www.ebay.co.uk/itm/XRS-GR-120...UAAOSwSdZWgYzS

Makers website-
http://www.aev.co.uk/index.php

I'll see if I can get some pics of the buffer, but it also now has heatsinks but still should be able to see the chip pins.

anything is good. i just have an appreciation for seeing what's achievable I'm semi - excited at the thought of doing one successfully mainly because I've avoided the challenge so far.

It's a bit like when I had a handful of bad SC boards doing nothing, now that I have several 5336 SU boards that you can't get or ludricously priced I'm keen to have some spare.

[tw2005]

Re: Panasonic Plasma SD, SU Buffer IC repair

Well the chips arrived today and I'm a little excited

The board was pretty clean and ready for these so I got right into it.

Hand soldered with plenty of flux and then a hit with the Hot Air. Some of the pins a smidge out but pretty good.

Looked like it was soldered ok, belled out the outputs and all the pins looked good, resistance check was ok.

time to fire it up, Hmmm. 7 blinks, recheck, 2 more goes, 7 blinks. Noticed the SC LED not lighting

SC2 lead missing. Forgot I borrowed this for a board test in something else.

Fixed that blunder, turned it on and running. Sweet!

Run through the test patterns, perfect, no hint of any issues.





3 minutes later, CLICK

7 blinks. Nothing hot, no smoke, the IC replaced is fine but now the very first buffer IC on the SU, Toast, shorted outputs.

So I know some of you have done some boards, have you had a similar experience?

Am I about to replace these buffer ICs one by one on the same board?

Otherwise , very happy getting the chip on.

Only got 3 of these chips because i was unsure I could do it but I think I'll be getting some more so long as I get this board running.

[tw2005]

Chapitre Deux - Panasonic Plasma SD, SU Buffer IC repair

SU board repair - chapitre deux

Right then, take two

These were the images I was about to post 2minutes 55secs into it's first run up.

It's lasted about an hour now on full white and the only thing I've spotted is a tiny bit of maldischarge in the upper right area. I'll see how it goes and swap a known good board in to see if it's the SU.

Interestingly the ST30 I recently fixed the SC had the exact same issue and I adjust Vsus down by less than a volt and it's gone. may do the same here.

I got the ICs from e-best_trade and they look authentic and at this time $4.60 USD so it was about $24 AUD delivered for 3. I went conservative in case it was an epic fail but I think this is viable.

I'm seeing in some cases $80-90 USD just for the SU board plus freight and exchange rates and for me potentially $200 for a set.

[flocko]

Re: Panasonic Plasma SD, SU Buffer IC repair

That is one more string to your bow, I have found the IC fail in twos, no clue why on these, we can still pick them up for about £25-30 on eBay so for me as a customer repair not worth repairing. have you found a sealer to use yet ?

[tw2005]

Re: Panasonic Plasma SD, SU Buffer IC repair

That is one more string to your bow, I have found the IC fail in twos, no clue why on these, we can still pick them up for about £25-30 on eBay so for me as a customer repair not worth repairing. have you found a sealer to use yet ?

I know what I want but looks like it's US of A and could end up being $70 by the time someone helps me get it. It's in the UK but in commercial quantities.

I found something in black from ACC silicones in a cartridge AS1821.

I'd love to have these looking original but if not then I want flowable self levelling, not paste.

I know you suggested RTV Grey auto gasket maker but it's too thick for my liking.

Just knocked up another SU which needed 1 chip. Will give it a longer run tomorrow but lasted longer than a few minutes

Same maldischarge, same spot. Doubt it's buffer. think I'll give it a small tweak on the Vsus like the ST30

[tw2005]

Re: Panasonic Plasma SD, SU Buffer IC repair

That is one more string to your bow, I have found the IC fail in twos, no clue why on these, we can still pick them up for about £25-30 on eBay so for me as a customer repair not worth repairing. have you found a sealer to use yet ?

Trust you're keeping the dead stock for when you can't?

[flocko]

Re: Panasonic Plasma SD, SU Buffer IC repair

Yes mate piles of SC/SU and SDs all wanting buffer ICs (R2A20250+ AN16520A) I did the same with LG and Samsung boards over the years and never got round to repairing them all,I still have loads of boards that I do not list on eBay as it is. The days of the plasma set have long gone I fear, but with LED sets failing at a good rate there is plenty to keep me going.

[gdawg]

Re: Panasonic Plasma SD, SU Buffer IC repair

I will have to try the method of cutting the pins. I did one with hot air and the board blistered. It was just an experiment at that time.

I tried another with hot air and successfully removed it with no trace damage.
Again I was just practicing.

I removed the silicone with my finger nail.

I never finished a repair, only because I was worried about blowing up an SC board if I screwed up.

I now have renewed faith in attempting the chip replacement. Thanks tw2005 for the thread and for everybody's input.

I feel a little more confident in SC repairs ( thanks for everyone's help) so maybe I will continue my attempt on the buffers next time I have a failure.

[tw2005]

Re: Panasonic Plasma SD, SU Buffer IC repair

Yes mate piles of SC/SU and SDs all wanting buffer ICs (R2A20250+ AN16520A) I did the same with LG and Samsung boards over the years and never got round to repairing them all,I still have loads of boards that I do not list on eBay as it is. The days of the plasma set have long gone I fear, but with LED sets failing at a good rate there is plenty to keep me going.

Maybe but there's still people who want to hang on to their Panny PDPs.

Ii never have much luck in the LCD department. So hard to find stuff to work on I grabbed a 40" SONIQ, Standby, won't turn on. Voltages ok, even reflashed the firmware.

Mainboard has 1 main MSTAR chip, a few regs, an amp IC and F/all else. Needless to say no go and money lost = Junk TV

maybe you could send some of those boards across with the next batch of convicts?

[gdawg]

Re: Panasonic Plasma SD, SU Buffer IC repair

Yes mate piles of SC/SU and SDs all wanting buffer ICs (R2A20250+ AN16520A) I did the same with LG and Samsung boards over the years and never got round to repairing them all,I still have loads of boards that I do not list on eBay as it is. The days of the plasma set have long gone I fear, but with LED sets failing at a good rate there is plenty to keep me going.

It seems everyone thinks the "new" led technology is better than plasma. I am a plasma fan only because I like a quality picture.

I have a Pioneer Elite I bought new 9 years ago. Still running great. Its only 720p but I would put it up against any new LCD.

The sad part is I repaired 2 50" Panny's and have them listed on Craig's list for a month. Not one phone call on either. One's a 2012 and one's a 2010. Only asking $220. So you are right, I fear the plasma fans are going away.

To me, when you look close on the new LCD's there is a lot of artifacts .

[flocko]

Re: Panasonic Plasma SD, SU Buffer IC repair

The AS1821 RTV black silicone adhesive is listed on Farnell + RS over here bit pricey at £22.00 +vat for 310ml. but whatever floats your boat. I still use the grey RTV no problem with flow only if left open then it dries out and wont come out the tube, but that is the same for any 1 part room temp vulcanising rubber silicone

[flocko]

Re: Panasonic Plasma SD, SU Buffer IC repair

I stopped selling sets a long time ago, when you can make more from parts , then the set can be sold for there seems to be no point ? It does come hard to have to part out a working set. but the fact is the parts bring in more money then a two/three year old set.

[gdawg]

Re: Panasonic Plasma SD, SU Buffer IC repair

Sorry tw2005. Kinda got off the subject at hand. I am going to go thru all my Panasonic buffers and see if any show shorts so I can try my luck. Thanks again.

[tw2005]

Re: Panasonic Plasma SD, SU Buffer IC repair

I stopped selling sets a long time ago, when you can make more from parts , then the set can be sold for there seems to be no point ? It does come hard to have to part out a working set. but the fact is the parts bring in more money then a two/three year old set.

How true. My wife and I were just discussing that fact as I fixed these boards however it goes against my philosophy. Prefer to bring things back to operation.

[flocko]

Re: Panasonic Plasma SD, SU Buffer IC repair

Yes I prefer to bring things back from the dead, I still offer a customer repair service +refurbishment on selected boards, as well as selling component parts and boards for others to use in there repairs. But if I end up with a working set on my hands it will be parted out