If it's a clocking problem, you be getting Pod timeout errors rather than power fail errors, wouldn't you?
Not necessarily - for example, I've had the same problem on an L-shaped S.I. boardset which has been 'fixed' by changing the two resistors that work alongside the crystal.
It's most likely that your LM309 is sagging just a little. If you disable power error trapping, you'll probably be fine.
Tried that but no luck I'm afraid.
It's not a problem endemic to Night Driver boards, as we've done quite a few and never had the issue you are describing.
I see - well, this is a first then. :)
Have also tried varying the voltage but to no avail.
How could you do that without bypassing the LM309?
Well, because I'm only testing this (but don't have the original AC PSU) I've rigged it up on my test bench and bypassed the LM309/LM323 by wiring the relevant DC voltages directly to the correct tracks on the board. Seems to work too - at least, with a normal 6502 CPU. Phil _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist