Cut it out and replace it.

Desoldering corroded parts of the board are tough, as you know if you've ever worked with corroded boards.

Traditional desoldering methods just don't work real well. Cutting components out, and heating 1 leg at a time from the solder side of the board and carefully pulling through the component side has the best success rate for me.

PIAs aren't tough to come by. Yeah, they aren't cheap, but there are LOTS and LOTS of pulls out there. Look up Andrew, he has plenty of good clean Motorola pulls.

https://pinside.com/pinball/forum/topic/fs-6821-pia-mc6821p-starting-at-3-each-legit-no-remarks-tested

Having said that, I've got concerns on that board being salvageable. It's got a lot of creep on it from the corrosion working around. All the spots where there are black dots in the traces (look, for example, above U51), that means the solder mask needs to be removed from the board, and sanded clean down to bare copper traces, which then need to be tinned or otherwise sealed. Otherwise, it'll continue to spread under the solder mask, and eventually, will eat through those fine traces on the component side of the board.

Any board is salvageable, but not every board is *economically* salvageable.

I would also suggest removing the lamp matrix column resistors and transistors, and convert to mosfets with jumpers in place of the resistors. The lamp matrix column section of that board is heavily baked, and heat will just continue to make it worse. The mosfets run much, much cooler than the resistors, and they won't continue to cook the board.

Once you've sanded it to bare copper, there should be nothing left to neutralize.

Yes, you'll want to seal with something, clear lacquer, conformal coating, nail polish, etc.

I've got a Sys11 test fixture, and you can do a pretty thorough job repairing boards with it.

I'm not sure about the Rottendog board in a Sys11 (no letter) - but I don't think it's compatible. If you look at the Rottendog site, the game isn't listed as compatible.

http://rottendog.us/MPU011A.html

If the person offering to repair it for $165 is reputable, I'd jump at that - I don't think that I'd tackle this repair myself.

I've heard of some technicians who will get a board with damage like this working completely, and then seal the entire board with some sort of acrylic paint coating, with the theory that if oxygen can't get to the corrosion, it can't spread... but I'm wary of this method myself.

Definitely ask lots of questions, to be sure