Just to let you know... an A500 PSU will probably not do it and thus it can be power problems. When I had my A1200 hooked up to an A500 PSU with B1260, 2.5"HD and external diskdrive the PSU had to be turned on, off and on fast again just to get the {bleep} to power on, without external diskdrive this wasnt the case and if I installed the PCMCIA ethernet card it wouldn't boot at all no matter what (can't remember if I had the internal scandouble installed at that time though). The A500 PSU is more powerfull yes, but only to some extent... I ended up using a 200W AT PSU with the mashine and now it work perfectly even with SCSIkitIV, internal soundcard and iocard (no scandoubler though, it's in my A4000 now). :-D
