From the looks of things... very fixable. You need to clean up all the acid with a 50/50 mix of vinegar and water to neutralize the acid.

That still could have problems with the traces underneath the chip being eaten away. I just did one of those boards about a month ago. It took several HOURS of cleaning/scrubbing just to be able to do some soldering. Then a few more hours of continuity testing finding the breaks in the circuit path from the corrosion. Turned out there were three traces underneath the chip on the top side of the board had been eaten away at the solder pads (found by also using a high powered magnifier lens). Ended up running several jumper wires on the back side of the board to restore proper operation of the switch matrix. For what I had to charge the customer to repair this board, he could have bought one of the brand new reproduction boards instead.

+1 I would add, after neutralizing the acid, scrub (gently) the whole board down with a toothbrush and rubbing alcohol.

Ken's right about that, I've seen that many times myself. Of course if your going to fix it yourself it's really just your time that you'll have invested, parts are cheap through Mouser or Digikey.

I would say buy a new board and ebay that to someone who does repairs.

It is fixable, but unless you have a lot of experience you could do more damage then good.

Even once you fix it there is still a chance that you didn't catch everything. If you don't it will eventually fail again.

You have more acid damage then just that one burnt chip. U16 and U20 both have acid damage. The resistors around them have acid damage.

Not sure what techs charge around you but around here the cheapest I know is 40 an hour. Do the math to decide at what point a newer more reliable board is worth it.

Save yourself the headache and contact Rob Anthony at www.lockwhenlit.com to have him review the pics. If he says its repairable you can send him the board to fix, fast and reasonable. He has done similar repairs for me, and worse (think of repairing a board with a hole burnt through it)

I look at this way.. It doesn't work now, so why not try to fix it? I mean unless there is just no other replacement and this board has to be refurbished or the whole game is trashed. But that's just me,I want to learn this part of pinball very badly so I believe the old saying " You have to start somewhere
"
Sounds like you can get an replacement so I think if you fail at the repair then just go get a New board.. All you can lose is some time and a few bucks from what you would have sold the acid damaged board for on E-bay.

I would suggest if you want to learn how to do board repair, buy a cheap game. I cannot see him screwing up the too much by working on the cpu board, but I have seen people fix things on one board, only to have it fry something elsewhere.

The traces on these boards are very tiny and extremely fragile. Plus they lift off easily with even the most careful desoldering (ask me how I know).

Question, when you use the vinegar and water to neutralize the acid, do you just scrub it with a toothbrush and let it dry or do you rinse the mixture off? Or is this what the alcohol scrub does?

Thanks! Bill in Indiana

You have to rinse off the vinegar mix then scrub with alcohol. After that rinse off with water and blow dry with canned air or hair dryer.

You could fix it, but it would be more trouble than it's worth. U16, U20, and quite a few resistors/capacitors need to come out. Then the alkaline damage needs to be repaired and further alkaline creep abated. The darkened traces on the back of the board leading to U20 are being slowly eaten by the alkaline. You'd need to jumper all of those traces.

At $140/board, get yourself a Rottendog replacement, transfer the ASIC, processor, and game ROM, and sell what's left to someone for 10 or 15 bucks.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

I agree your out nothing but time.

Oh and Ken is right about everything I have ever seen him post.

He does not guess and I have never seen him post unless he knows from first hand exp.

Very knowledgable man.

Best of luck with your repairs.

Congrats. Care to share who did the repair work so others with the same problem can have hope?

I'm glad you've got your board operational again.

Of course you're allowed....And encouraged. We all know Rob Anthony, Clive Jones, Chance Tess, Steve Kulpa and many others who do great board work. If you've found another we'd certainly like to know that another option exists.

Clive is my go to guy. They are all good