iBook G3 - Only powers on sometimes, crashes often

I have an iBook G3 I got off eBay, so right away I knew it wasn't going to be easy. It's the larger 800 MHz model.

Bought a cheap charger and installed Mac OS 9 Lives on it. Right away I have issues where it crashes... a lot. Load up Oregon Trail and I can't even get through a single game without crashing at least 3 times. Oregon Trail 3 wouldn't even run.

I leave it be for a week and when I go back to use it, it won't power on. I take the battery out, do all the different power button combos and still, nothing. Occasionally I can get it to come on, but those times are few and far between. Battery charge doesn't appear to be the problem, as it appears fully charged. Battery is flacky, but once it's on it stays on unless the OS freezes/crashes.

I ended up getting a partial refund for most of the cost of the system.

I ended up getting a 900 MHz smaller model iBook G3 with the goal of replacing the logic board. Used the same OS 9 Lives disk to install, used the same charger, etc. Already a much more reliable system. Didn't crash at all... well except for in Frankenstein: Through the Eyes of the Monster but that seems to happen on every Mac I try sooo... if I want to see Tim Curry as a crazy drug addled Victor Frankenstein I'll have to deal with it.

I've found a lot of conflicting info. Would a bad hard drive or RAM prevent this from booting? Could the logic board be bad? I thought that only affected graphics. Thanks!