Powering the Commodore Amiga 500 with the Rigol DP832 supply

a500_powered

So thanks to Mike/amigamech for still having brand new stock of 5-pin A500 power connectors that he could ship quickly.

I used information from http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_Power_supplies/amiga_power_supplies.html for the various pinouts.

I have ordered a picopsu really small power supply to replace the big normal clunky one. I like the idea of using new and still available components where we can.

This is a stock A500 with the only addition being my custom A501 card.

Besides just an excuse to put my DP832 into action, it also gave me the ability to confirm the power draw requirements, and make sure I don’t exceed them with the pico.

The A500, Rock Lobster rev 5, motherboard draws (as you can see in the picture) 20ma on the -12v rail, 22ma on the +12v, and 1.5A on the +5v rail when idle. 8-9 watts for a running machine sounds pretty low to me!

When the floppy runs, which is probably the only other power intensive operation, this 1.55 amps goes up to around 2 amps maximum.

I could try playing some audio(op amps) and doing some serial operations, as they should exercise that -12v rail.

Pretty cool. Also thanks to Dave McGuire for helping me understand negative voltages a little bit. I’m really not used to playing with them, and connecting the positive output of the isolated -12v channel to the ground of the +5v and +12v channels definitely gave me pause. A lack of smoke and a multimeter quickly confirmed that this was fine, if only counter-intuitive for me.

The A500 boots normally and works as it should.

 

About the author

keith

Amateur Electronics Design Engineer and Hacker