Hmm - Just today I cracked open a Craigslist find - an SE with an SE/30 MB installed, and exactly the same issue with battery explosion, and the "Irregular Vertical Rasters" from the website referenced upthread.

I did an alcohol scrub, and tried to clean the contacts on the ROM SIMM, which had a black coating that didn't really seem to respond to either alcohol/Q-tips or a couple passes with a pencil eraser.

I'm going to let things dry overnight, and then perhaps re-clean what I can, and then go from there.

Machine did come with an Asante MacCon Ethernet card, so it was worth it even if the rest of the machine doesn't pan out.