At 02:41 PM 5/22/99 -0400, you wrote:
>Bob I'm pulling up your page now but wanted to ask about the power supply.
>Are you using an inverter to a normal PC power supply or did you work
>out a direct DC-DC converter?

Hi Byron,

It's a DC-DC converter I made myself. Nominal 12 volts in. +5, +12, and -12
out, as well as PowerGood signal. It'll run the machine with as little as 8
volts in, so I have it set up to power up as soon as I hit "door unlock" on
my key fob, so it's booting as I start the car.

It's fairly low-tech by today's standards. I wound the transformer on a
molybdenum permalloy toroidal core because I didn't want to do much
trial-and-error and those cores are way more forgiving than ferrite pot
cores. Toroids also have a very contained field and I've been using these
from Arnold Engineering since the 1970's. I forget what frequency it runs
at, pretty low, probably 30KHz. It's very efficient, though. It draws
between 2 amps and 3 amps depending on cpu and disk load. 4 amps at spin-up.

Cheers,
Bob