Akai 42" Plasma, no picture
 

I just picked up an Akai Plasma PDP42Z5TA to look at, it's about five years old and the screen is dead.
It's still in the Van but I thought I'd pick your brains before I take it apart.

Owner said the sound was working (not verified yet) but nothing on screen.
I tried it at their house, clicks when plugged in, the Standby light goes from Red to Green but nothing on the screen, I heard no sound but it was not hooked up to anything either.

If it was the power supply caps I would think the standby light would stay red, no?

Probably buffer boards and/or Y-main board. Very common on Samsung built TV's. You will need to check the voltages at the y_main. Around 180V, 60V. There is a sticker on the PDP of what it's supposed to be. Check the PS carefully. Usually it it's a cap, it's one of the smaller ones buried among the others. The PS may still power up with a bad cap. There is a lot of info on testing the buffers on the internet. They are expensive used and new ones are NLA. If the buffers are shorted, more than likely the Y-main is toast. Inspect the buffers carefully for burn marks or holes. These are on the right hand side looking from the front.

Well I got the back off, no small feat with all those screws.

I found this on eBay, fits the symptoms, found a blown fuse on the YSUS board.
Do you think this is worth a try?
This isn't my set so they owner will have to risk the $ to buy the part but I do stand to make a few $ if I get it working.

http://www.ebay.com/itm/Akai-PDP42Z5...item27b5ce1a5e

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you need to check the buffer boards. if you fix or replace the Y-board and don't check the buffer, you will blow the Y-Main again.
http://www.youtube.com/watch?v=5hVi5gd0aec

looks like a LG made set. Generally they are Samsung. Dont worry about the buffers. I replaced lots of those with success. Get it from Coppell tv repair. Do NOT buy it from China! it's a pain to replace as long as you are VERY careful removing the old one

Do you think it might be wise to lust let Coppell repair the YSUS board for $65?

I don't know how much they want to risk on this set, I'd hate to do that and find out it had another problem.

I picked up a LG 42" plasma, same problem, same fix. Got the module from Coppel TV and installed it myself. It was a SOB MF to unsolder / solder, some of the pins connect to a large ground plane and really soaks up the heat! Also be careful with the ribbon connector at the lower right, easily broken.

Bottom line is it's fixed and works great!

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Well I relayed the price options to the person, Chip alone, vs rebuilding the board vs risk that something else could be wrong + labor, we'll see what she says.

If she decides not to fix it then I'll probably wind up with the set.
I'd probably be willing to risk the price of the Module alone just to see if I can make it work.
The experience might come in handy if I ever need to fix my Panasonic.

$65 is not a bad price to have it repaired by coppeltv. he guarantee's his work. The repair is is a pain to do with just a soldering iron and the board is easily damaged. Most of the speckles can be adjusted out but never completely go away. Check the fuses on the Z-board(the board on the opposite side of the set with the 2 large copper ribbons). Generally on LG made sets, the Y-main repair is usually all it needs but on occasion, the Z is bad too.

Well I heard back from the owner, they don't want to fool with it so the set is mine. I actually prefer that outcome, I'm not comfortable doing work for others when I don't know what I'm doing.

I would like to go ahead and replace the chip on the YSUS board myself just for the "fun" and experience of doing it, besides, after removing the fifty screws holding the back on the rest can't be that hard.

How do I go about ordering a chip from Coppel's? Just write them and say I need a YSUS chip for an Akai model xxxx?

By the way, I haven't said thank you yet for the help, so thank you! :yes:

Here's a pic of the back side, is this a Samsung built set?

LG built. There is a number on the label on the heatsink. That's what he will need. Similar to: 6871QYH953A but more than likely a different number

Found it, sometimes it's easier to take a picture than write it down, especially in an awkward location.

I got the Chip off eBay from Coppel's, $32 shipping included.
I'll post again after I get it installed!

That's a good price!

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.

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.

I haven't checked the numbers yet but the Buffer looks a lot like this one.

http://www.ebay.com/itm/Akai-PDP4273...item19cbb95b16

best to buy some used ones. part numbers will be on the boards. Something like this: 6870QKE010A

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.

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.

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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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.

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.

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

I plan to

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.

That's the wonderful world of Plasma!

Yea, the wonderful world of junk. I dont touch them anymore. i shoot any of them I see for the fun of it. They are not worth fixing unless its a newer one, such as the LG slimlines, or etc...

the old fat heavy junkers with bad buffers/sustain, they are garbage. By the time you pay for a new/rebuilt sustain and buffers, you could have bought 2 brand new ones for that price.

And not to mention, god only knows how many hours are on that panel.

I think the one I see the most of are the PDP42V6 variants that have the blown buffers. I have one now with bad buffers and I tried to rebuild the sustain, it blows every set of buffers you put in. So its junk as well. 3 good panels and not 1 good set.

Yes so true. I only use Sony LCD's. 52" and 47". Both were free but needed minor repairs. Have been working great for over 2 and 1/2 years. Both were tcon issues. Lcd's are sooooo much easier to work on unless there is a panel problem. Lots of Sony's and Samsungs with bad panels. I junked about 50 of them for parts. got lucky with 2 my sony's.

I have a 47" Sony bravia LCD I cant figure out whats wrong with it. it seems to have 2 large heatsinks on the t-con board.

first turn it on, picture is doubled/flashes/ghosts and appears to be missing odd scan lines.

as it warms up, the better it gets and it gets perfect. slowly though its taking longer and longer before it gets better.

Many of those bravia's have panel issues. The chip that is embedded in the ribbon cables lose their bond. When you first turn on the tv, take your hand and whack the corner of the bezel (usually the upper right side) and I bet the picture will straighten out. It's barbaric but it works.

You can also twist the set slightly and it will work also. A hand on each corner. Could be a bad tcon but you should make sure first. I twisted and banged on mine for days to make sure before I spent the money. Yeah some tcon's have fairly large heatsinks. Mine has a 2 piece tcon. Just replaced both to make sure. It's a 2007 model but is considered "old" by today's standards. LOL I thought my roundies were "old".

I've run into quite a few of those 2008-ish Sonys with bad panels. Also seen a couple Mitsubishi and some Toshiba, and of course Samsung (they made all of the panels I've seen with that bad bond on the ribbons). There are some Youtube videos showing how to "fix" that, by putting shims against the chips to restore the connections. I feel OK with it for myself because when it fails again I don't have to answer to anyone but myself. (And my wife.) I wouldn't do a fix like that for someone else. I also worry about the heat those drivers generate. They get dang hot, and with rubber shims in there the heat cant get away very well which I suspect will accelerate the demise of the chips. I have tried it a few times. Usually lasts a few months or less.
I have fixed the T-CONs on a few of those. I have seen the fuse open on them, and have usually found it opened because of a shorted MLCC somewhere on the board. New fuse, new cap or just crush the bad one, (if I can figure out which one it is) and good to go. I recently confirmed a couple of them I fixed about 2 years ago are still running.

Getting back on the main topic of this thread, I agree with everyone else...Trying to fix one of those plasma sets is risky at best. I usually tell people to take the money repair will cost and put it into a new set. Some sets I simply refuse the job. I'd rather have them pissed at me because I DIDN'T take their money than because I did and the set didn't last

I tell you one thing ive ran into alot lately is the hitachi and mitsubishi LCD projection TVs with burned polerizors in the engine.

Luckily I have been getting away with replacing the polarizors without replacing the engine.

Those are a whole different ballgame. Different issues than LCD or plasma. Yes i know DLP's have LCD's in them. Totally different problems. Sony's and hitachi's are the worst. Big yellow, green or blue blobs, blue spots etc

well yea, i know. its just a random thing that crossed my mind while we were on the subject. and DLPs dont have LCDs in them, they have DMD chips.

the Sony used a weird setup. they didnt use a passive LCD panel, they used a transflective panel that loved to FAIL with the green blob.