I wouldn't try running that setup on an A500 PSU.
When I got my Blizzard 1230-IV I had a few crashes on the A1200 PSU,
when I got the SCSI-IV kit I blew both the A1200 and an A500 uprated
supply.
(I didn't even have a 2.5" hard disk!)
The external scandoubler might be taking a lot of juice, I'm not sure
- but 128mb of RAM will definately eat power (especially if it's 1k
refresh!).
Get a 200watt PC AT or ATX power supply and follow online conversions,
or better still look for a Wizard Powerbox or Goliath PowerSupply.
:-)
I agree though, the A1200 wedge is far nicer than the towered A1200s.
Keeps character.
I've had a few moans about there never being a small GFX card for the
Blizzard 1230/40/60!