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  #16  
Old 01-25-2012, 08:50 PM
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mstaton mstaton is offline
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That's a good price!
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  #17  
Old 01-27-2012, 08:36 PM
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Got the chip today, been working on getting the old one off for the last two hours! I really would have let them do it if I knew it would be this big of a pain.


Two things would have made it easier, some Flux and some fresh Solder wick.
Wicking the solder did very little to actually loosen the chip from the board, I wound up prying it hard enough to break the chip, then I removed the remaining pins one by one. I also knocked one smallish round capacitor off the board, it's a surface mount and I got it back on with little problem.

Trying to clean the remaining solder out of the holes so I can get all 30 or so pins in the board at once I managed to shove one of the sleeves through the board.
I repaired this with a fine bit of wire through the board and up to the trace on the top side.

I'll be amazed if this thing works 100% when I'm done, if at all.

Anyway, off to the Shack for some Heat Sink Paste, fresh Wick and maybe a vacuum de-soldering thingy.
Probably should have done that step first, live and learn.
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  #18  
Old 01-27-2012, 10:31 PM
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Got it together, some success some failure, mostly failure.

The set comes on now but the screen has bands of different light, one section is bright white, the others are darkish and flickering.

After about ten seconds on it started making arcing and snapping sounds so I turned it off.

Found a small connector I left unplugged, plugged it in and tried again, same thing on the screen, a little longer before it started snapping, I didn't turn it off this time, I wanted to see what was arcing, I expected it to be somewhere around my solder loints on the chip but it was actually one of the Buffer chips glowing orange and smoking, I quickly turned it off hoping to save my new YSUS chip.

Some of the other Buffer chips were pretty hot as well so I guess the buffer board is hosed, I am NOT going to try to replace those chips, the video on YouTube makes it pretty clear it's not a job for amateurs.

The screen was still lit when I shut it down, the fuse to the YSUS didn't blow, what are the chances I just need a Buffer Board now? Or should I quit while I'm not too far behind.
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  #19  
Old 01-27-2012, 10:33 PM
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I haven't checked the numbers yet but the Buffer looks a lot like this one.

http://www.ebay.com/itm/Akai-PDP4273...item19cbb95b16
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  #20  
Old 01-27-2012, 11:02 PM
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best to buy some used ones. part numbers will be on the boards. Something like this: 6870QKE010A
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  #21  
Old 01-28-2012, 12:32 AM
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Well phooey, there are three chips on the buffer board that are cracked and melted like this one.

I strongly suspect something wrong with the YSUS board caused this, I can't see three of the chips suddenly deciding to snap crackle and pop, probably something I did wrong so there's no point looking for a Buffer board until/unless I fix that first.
That probably means finding another YSUS board, maybe one with a bad module so I can transfer my new chip to it, assuming I can get it off in one piece. Then getting another buffer board.

Or hauling the thing down to the recycling center.
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  #22  
Old 01-28-2012, 01:35 AM
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Regarding the "Is it worth it?" question, part of the answer is if you value the knowledge gained in the repair process for this set, and if you anticipate repairing more flat-panel TVs in the future. For this specific set, you may already be at the point of diminishing returns considering the likely quality/value of the set when you finish compared to what you can buy new today (1080p, built-in HD tuner for under $500, neither of which this set probably has). This one is probably 1024x768 (yes, non-square pixels), the typical "HD" resolution for 42" plasma sets before the 1080p models came out.
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  #23  
Old 01-28-2012, 01:49 AM
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Hi Chris, I definitely don't need this set, it was just a freebie I thought might be fun and interesting to get working, however at this point it might just be too costly to go any further.
If it was a better set i.e. Panasonic, Samsung, Sony then maybe I would.

I'll keep it for a while and look for some cheap used parts, if nothing turns up then off to the recyclers it goes.
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  #24  
Old 01-28-2012, 11:02 AM
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...

Last edited by andy; 12-05-2021 at 08:16 PM.
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  #25  
Old 02-04-2012, 11:05 PM
mbates14 mbates14 is offline
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With plasmas, ive learned the rule of thumb is this:

Y sustain and buffers MUST be changed TOGETHER at the same time!!! They work hand-in-hand, and any failure in one WILL Affect the other in most circumstances.

I throw all my plasmas away when I get them with blown buffers.

Also, if the screen is lit up, whether its bars, or whatever, as long as the screen is LIT. it confirms proper operation of the sustain module. This is an amplifier module that drives high voltage from a waveform generated in the control logic, to the panel. This allows the addressed electrodes to discharge. This high voltage is ALSO passed through the y-address buffers, which is why they blow up, the silicon dont last as long constantly pulsed with changing currents/high voltage.

plasmas are just one huge design flaw. PERIOD.
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  #26  
Old 02-16-2012, 05:11 PM
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You guys are all on the right track. Cut the pins and remove them one by one to keep from destroying the board. Replace STK, sanyo STK,s are ok, seem better than the orig LG made ones. Keep the buffer board disconnected when you put the the board back in. If you can hear the STK working, then connect buffer, get ready to pull the plug if the screen dont look right, the buffers will destroy your ysus fast. It damages the mosfets first. Speckles yes in LG sets are ok, tweak the VS drive on the power supply, 10v +- is safe, sont ruun it above those limits. I have found that speckles seem to dissapear when the buffers wear too. LG panels age quick, when they have reached near ill fated doom, they have black speckles followed by red and green and blue sometimes. Letterbox mode kills panels too.
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  #27  
Old 02-16-2012, 11:38 PM
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He already scrapped the set. I sent him a good buffer board to go with the rebuilt ysus. Went up in smoke. . Had to be something else wrong with the ysys. I does happen occasionally. I usually get lucky and it works but sometimes replacing the STK IC does not. I have one to do on a 50" Vizio(LG) this weekend. There is 2 on that one
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  #28  
Old 02-17-2012, 10:14 AM
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Quote:
Originally Posted by mstaton View Post
He already scrapped the set. I sent him a good buffer board to go with the rebuilt ysus. Went up in smoke. . Had to be something else wrong with the ysys. I does happen occasionally. I usually get lucky and it works but sometimes replacing the STK IC does not. I have one to do on a 50" Vizio(LG) this weekend. There is 2 on that one
Replace both! One bad IPM will harm the other, and when u replace the faulty one, there is like a 75% chance that the harmed one will go or worse it will destroy the replaced one, use matching pairs too. like yppd-j016a match with a yppd-j015a, or b's, c's e's
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  #29  
Old 02-17-2012, 02:08 PM
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"Book em Dano!"
 
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I plan to
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  #30  
Old 02-18-2012, 12:12 AM
mbates14 mbates14 is offline
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I got 2 scrap PDP50X3s here that both had blown IPM chips.

They were fixed and blew again, so i said screw it. One within 30 minutes. noticed the sustain getting louder, and more sparklies. POP.
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