Hi, I recently got my NorthStar Advantage up and working, it had suffered when I first powered it on with a failed tantalum capacitor on a SIO board. I didn't originally spot the soot and debris as the machine has two SIO boards and of course the failed cap was on the hidden board :-) Followed advice on earlier thread 'Smoke on the Horizon', I replaced the 6 tantalums with new ones. I also now have a variac and the PSU was bought up gradually, no problems at all on that side. It now boots into either CP/M or NDOS 1.0.0, and on the latter it has GBASIC which is the extended Basic supporting the wonderful graphics ability of this machine. Unfortunately GBASIC often crashes with a 'RAM Parity Error' message, I guess most of the RAM is OK else it wouldn't boot. The Technical Manual refers to the dealers Diagnostic Diskette, and shows a series of tests to identify faulty RAM chip. I don't wish to try and re-seat all the chips as when I tried this on my Pet it has failed to display anything since (another pending repair project). I've just bought some hard sector floppies, so can send a blank floppy to anyone who can copy the diagnostic disk for me, I would be very grateful. Regards, John