Hi!
What you need is one of those old heavy a500 psu's that pump out 60watts! i have an a1200 with a quantum fireball 5400rpm 2gb drive running with that 60watter no problems at all
if you cant get one.. get an AT pc power supply and mod a spare amiga power lead into it! imagine 250watts of spare power
if you need any help with this then please e-mail me as i have done dozens of these psu's
J