From my own (accidental) experiments, I found that if a
C128
powersupply is used on an A500, the machine will seem to work, but
appear to have a flaky floppy and sound. Most frustrating - I though
my A500 to be junk material until I used the proper supply.
The C128 on the other hand didn't seem to mind the Amiga supply, not
surprisingly.
Joe.