Watching my MPU go up in smoke - In need of a DE MPU

Literally...

So I have two broke TFTC's....The one I traded with Devil and another one I'm fixing for a friend. Both have board issues. The second one I had identified as a bad PIA on the switch matrix. Ordered a new 6821 and buffer chip and sockets. I have a friend that does solder work for a living in building power supplies for cell phone industry. I'm an ok solderer, but this PIA had been replaced once before (no socket) and had a couple of trace jumpers so he offered to come over and repair it.

Well, he wanted to show me a trick I'd never heard of...Using a heat gun to soften all the solder points on a 40 pin IC at once. He did use wick to remove most of the solder at each point. Then using the heat gun (600 deg and 1000 deg setting on mine) at 600 deg, heated the IC a few seconds and out it popped. Cool! The 20 pin buffer chip (much smaller) is right beside it so he decides to do this one too...only this time he inadvertently put it on 1000 deg! within seconds the board starts smoking and all the traces where the 40 pin PIA was go up in smoke as the board bubbles.

So, in the wink of an eye, I see my $250 board go up in smoke. He felt bad, I felt sick, but I let on no big deal....Didn't want to make him feel worse. He thinks he can take it to his 'shop' and fix all the traces, but I don't think so....

Anyone have a nice used one they want to sell? Sending the other one off to Clive...not taking anymore chances.

#2 12 years ago

RND

RawleyD

Pinside member

Roanoke, VA

14y 67,650 3,243 36

ouch. bad story bro

#3 12 years ago

JRK

jk2171

Pinside+ Frequent

14y 85,050 1,824 16

I think someone listed one on RGP today??

#4 12 years ago

robertmee

Pinside member

http://www.rottendog.us/mpu004.htm

Dang if I can find it I saw a post for DE power supplies, but not an MPU

#5 12 years ago

CMD

fatality83

Pinside member

Manchester, PA

12y 65,400 1,253 10 8

Not cheap by any means but if your friend can't fix it I would try this.

#6 12 years ago

CMD

fatality83

Pinside member

Manchester, PA

12y 65,400 1,253 10 8

I believe that one may work

#7 12 years ago

TJ141

Inactive member

Grand Island, NE

12y 21,650 351 4

Off topic, but i once was in a laundromat playing Bally's "Atlantis" when smoke started coming from what i thought was a coil under the playfield... i hit the power switch and walked away.

#8 12 years ago

AAW

Firebaall

Inactive member

I would have your friend pay for the board. You don't use a tool that's meant to strip paint off a chair on PCBs. I would be pissed.

Hot air definitely has it's place in solder reworking, but you best know how and what you're doing (and have the right equipment).

#9 12 years ago

DEVILinIRON

Inactive member

12y 28,150 445 6

Wow... That's terrible!

#10 12 years ago

robertmee

Pinside member

Quoted from Firebaall:
I would have your friend pay for the board. You don't use a tool that's meant to strip paint off a chair on PCBs. I would be pissed.
Hot air definitely has it's place in solder reworking, but you best know how and what you're doing (and have the right equipment).

My friend has no money, and he felt bad as it was. I know it was a bonehead move, but I allowed it...of course I was putting trust into someone that does board work for a living, so it backfired.

Live and learn....the search continues for a board

Rottendog at $300+ is an option but hopefully the last resort...

#11 12 years ago

???

pinmike

Inactive member

Bossier City, LA

13y 56,600 5,368

Those boards are hard to come by.Send it out for repairs

#12 12 years ago

robertmee

Pinside member

Quoted from pinmike:
Those boards are hard to come by.Send it out for repairs

Mike, you think it's salvageable? I mean all the green was blistered black and the traces were just floating in air...the substrate was gone. And this is a dense area of traces....all the ones from the 40 pin PIA to the 20 pin buffer IC.

I'd gladly send it out if I didn't think I'd get laughed at and waste the postage as Clive or Rob dropped it into the garbage

#13 12 years ago

???

pinmike

Inactive member

Bossier City, LA

13y 56,600 5,368

OP
Quoted from robertmee:
Mike, you think it's salvageable? I mean all the green was blistered black and the traces were just floating in air...the substrate was gone. And this is a dense area of traces....all the ones from the 40 pin PIA to the 20 pin buffer IC.

Ohhh! I honestly think that board is cooked and might not be repairable.But here's an idea,Take close up pics of the board and email them to Clive or Pete at K's arcade.com and see if they are willing or can fix it.Good luck.

Btw,Pinsider Stangbat Erik does great board work put up some pics and let's see what he thinks

#14 12 years ago

DAD

Pinballdad

Frozen

Unknown

12y 0k 1,137

Robert. Check your messages. I pm'd you with a guy in Michigan that stocks these and also does good work. Just an idea if you decide it's worth trying.

PBD

#15 12 years ago

robertmee

Pinside member

Thanks...I sent him an e-mail

#16 12 years ago

ESA

stangbat

KC Pins

13y 86,900 3,111 19

I repaired a DE CPU that someone had removed (actually pulled is probably the right term) the LS244 for the switch matrix and ripped most of the traces that went to the PIA and the resistor network. I had to run jumpers all over the back. It looked like a bowl of wire spaghetti once I was done, but it worked. Ugly, but not much else you can do and as has been mentioned, DE CPUs are expensive.

#17 12 years ago

AAW

Firebaall

Inactive member

I gotta ask. Pics?

#18 12 years ago

robertmee

Pinside member

Sorry didn't take any....He was going to take the board into work and let some of his colleagues take a look...They print pcbs and have all the materials to repair substrates supposedly. I figure couldn't be any worse giving them a shot at it. But it's likely going to be ugly and hacked even if it does work, so long term, I'd like to have an original unmolested board. I'm not holding my breath on it being repairable, although stangbat's post gives me hope. When I get it back, I'll post some pics.

#19 12 years ago

AAW

Firebaall

Inactive member

If it makes you feel any better, I found this mess on the back of some logic gates that were replaced. Love the 30 gauge wire wrap....

2012-01-07_20.27.40.jpg

#20 12 years ago

robertmee

Pinside member

Not terrible.....even the snot balls were a nice touch

#21 12 years ago

AAW

Firebaall

Inactive member

I laughed my ass off, when I saw it.

It reminded me of my school days, and 40 wire Xbox mods.

#22 12 years ago

???

Atomicboy

Inactive member

12y 81,150 7,318

That's not a bad jumper job actually. People sometimes get all worked up when they see what many call "hacks" but these, if done right, regardless of how ugly, were what was needed.

I redid my magnet board on my LAH. The traces and pads are so weak on this board, that the act of heating up to remove legs raised half the pads (something I had never done on any other previous board I have ever worked on). I had to jumper the hell out of it after. I looks ugly, but it's sound, and it works.

As for your problems Robert - that sucks. I had read about this method before, but I prefer to dremel the ICs legs, and dosolder each remaining pin. It takes forever, but seems more safe that applying a ton of heat to a large area of the board.

1 week later

#23 12 years ago

robertmee

Pinside member

Just a follow up....I bought a new board from chance Tess in mi (thanks pinballdad) and sent devilinirons hacked board to rework. 2 day turn around and should deliver tomorrow. Total cost for both boards less than the ones on ebay. Pending they look good when I get them tomorrow which I expect I highly recommend him for de boards. I still will post my burnt board pics when I get it back.

#24 12 years ago

AAW

Firebaall

Inactive member

Good to hear that you got some boards!

Having a dead pin around drives me nuts. Waiting for parts is the worst.

#25 12 years ago

DAD

Pinballdad

Frozen

Unknown

12y 0k 1,137

Great to hear you are moving forward Robertmee! Hope all goes well with Chance. I only used him once but it was stress and drama free so that was important to me Let us all know how it all works out in the end!

1 week later

#26 12 years ago

robertmee

Pinside member