The title says it all.. i've found apple info on faulty capacitors for G5's causing problems, but no info on the G4 Mirror Door.. although i don't appear at all to be the only one, Apple's threads on the subject dont seem to have any answers re the G4, plus they're old and locked. Anyone know how i can isolate the faulty component? The lockups are, or appear to be, entirely random... I do have the same video card as the G5...

oh by the way my system specs are over a year old, but there doesn't appear to be any way to change them... this site used to have more options and less advertising ;-( Anyone know how ?

Try it with only one stick of ram in there. Assuming you have more than one. If that doesn't work try using some different ram entirely. I only suggest this because my powerbook g4 (I know, different machine but still a valid point I feel) kept randomly kernal panicking and freezing up. Turned out it didn't like the ram in the machine; which was some no-name cheap crap that came with the system. Seems like some Macs that run OS X can be very picky with the RAM< they use. One bad module or a set of cheap crappy modules can cause all sorts of problems. I bought a couple of sticks of crucial and plugged them in and the system hasn't crashed on me since.