I tried that, but sadly it still didn't boot. My symptoms:

* Power on LC on back - keyboard lights come on very dimly. No other noise, movement, video, nothing at all.

* Wait a minute. LC starts "clicking" faintly about three times a second. Keyboard lights blink in time with the clicking.

* Push keyboard power button at any time - nothing happens.

* Flick power switch - nothing happens, machine just goes back to clicking.

Anyway as to my original question, Vintage Macs mailing list archive has the answers. I am surprised I didn't find this before but here it is.

It is most likely that your LC power supply's leads are color-coded thesame as mine all are, so in order:

Black (2 of them) = GND

Orange = +5v

Yellow = +12v

Blue = -5v

In addition, on the "business end" of the power supply's output plug, the

number "1" is lightly stamped at the first Black wire's position, and the

number "7" is stamped at the Blue wire's position.

Click to expand...

ETA: As these voltages match those on a standard PC ATX power supply I suppose I could run a very quick test by hacking up a known good PC PSU to see if I can get it working.