I think I've bitten off more than I can chew. :) So I got my first two retro machines at VCF Midwest in September, and the SE was super easy. Just needed to replace the battery holder, added a few mods - fun! But I also got a battery bombed IIgs that I'm definitely not experienced enough to figure out what's going on. I've attached a pic of the area that was bombed - it's been cleaned up a bit since then.
Obviously the traces near the former battery holder are toast, but I don't think that's what's causing my issue. The guy selling it demonstrated it could boot, which was cool, but when I got back, the ADB port won't accept any input. I have a Wombat ADB converter, and the power light comes on when it's plugged into the GS's ADB port, but keys just don't get read (and that's with an actual ADB keyboard/mouse combo, too). Based on the schematics - which I don't technically know how to read but I'm doing my best here - it looks like there's basically just one pin sending data all the way across the board to the controller chip, and the burned out traces don't seem to be related to that connection. (Although again, this is like trying to get a random poodle off the street to fix your transmission - I've come to that conclusion basically by spending a long time staring at the board really hard.)
Is this any kind of a commonly known issue? What would next steps be for isolating this and figuring out where the problem is? I've been told the IIgs is a fairly easy board to work on, so hopefully I'm capable of fixing this, I'm just stumped as to where to go next.
See the fault-finding discussion at this topic. The ROM 03 is notorious for battery damage, and that always requires extreme repair measures. I suppose it is easier to work on than a Mac IIfx or SE/30, simply by virtue of not being a multilayer board.
All of the vias and PTHs that were corroded need to be checked for continuity, because the likelihood is that most of them no longer work. Chips like the MC1377P will need to be pulled before the corrosion underneath them eats through the pins.
I would also neutralize this board with some vinegar to make sure none of the alkaline residue can cause further damage.