Today i bought a complete Atari 520 with a SF314 Diskdrive for 5$
Does anyone know what voltage the disktrive / Computer need and the pinouts?
I'm trying to replace the old transformators with new and smaller ones.
The 520 needs +5v, +12v and -12v to work. The external floppy should be happy with just +5v.
amprating... well, according to my own 520, it needs 3A on +5v and only a few symbolic mA on +/-12v. (12 volt input only needed for serial communication if I remember correctly)
If serial communication isn't important, you could try without the 12v. Or you get some cheap voltage regulator that can supply the symbolic currents needed from the 5v PSU.
The floppy momentarily needs up to 1A (spinning up, moving heads), although the one I got for my external drive only outputs about 450mA.
Trial & error from here I'm afraid.
Please let us know how your project pans out.