A little update: logic board is dead. It would turn on, ring a chime, spin up the SuperDrive, and the external display would catch some kind of signal for a second, but then no dice. Caps won't turn on, tried all keyboard combinations, resetting PRAM, nothing. Now to the imposibble task of finding a working logic board...I managed to buy a DLSD 17-inch PowerBook for 45$, which apparently turns on, no chime and it has no charger, but it's in great condition. Gonna arrive in a couple of days, hopefully it works.
Everything else is in great albeit used condition, keycaps are shining, but no major scuffs around the case. On disassembly, there were a lot of missing screws, and someone put the case screws into DVI screwholes... I was kinda scared to continue, but thankfully, heh🙂, no screws were holding the board so it was a little bit easier to take apart.
Well, at least this laptop's previous life was fun.