latest pickup: a very obscure Microsoft product -- the PCjr BOOSTER!
the battery is very nasty indeed. it needs to come out and i need to remove the corrosion on the holder.
it's a NEDA 1306A cell! 4.5V.
@tubetime weren't these used in compact Macs, too?
@tubetime @compu85 No! Compact Macs used the much more horrible 3.6V lithium thionyl chloride batteries, which are horrendously destructive when they leak. I've got a Compact Mac where the battery really went off, and there's a huge rusted spot on the steel frame above the battery holder.
@NekoEd @tubetime @compu85 The Mac 128, 512, and Plus had the 4.5 volt alkaline battery in a compartment accessible from the back. Those usually don't cause any damage. It's the SE and Classic models which switched to the 3.6 volt lithium battery on the logic board, which can often ruin the board when they leak.

@vwestlife @tubetime @compu85 Ah, they're all "Compact Macs", but I hadn't realized the first ones used a different battery. Though, the 3.6V ones aren't just in most Compact Macs; they're also in most (all?) other 68k as well as 601 to G3 PowerMacs (at least, I'm not certain when they stopped).

TL;DR: Get the batteries out!