The II, IIx, and IIfx should all be able to take the same power supply. One test to see if the power supply is working or if it is a problem with the batteries or caps or whatnot is to power on the supply "manually". It needs to be plugged into the logic board (the PSU requires load or it won't turn on), and connect between +3V and +6.5V to pin 15 of the PSU connector (this should be the pin furthest away from the PSU). If your PRAM batteries are fine, connect the + side of the battery to the pin 15 for just long enough for the PSU to power up.
I recommend using a volt meter to make sure you're only sending the single battery (+3.6V) to pin 15. I've sent the full +7.2V to the pin before with no ill effects, but it's best to be sure.
Be careful though, the pin right next to 15 is -12V. Bad things happen if that is shorted to something when the PSU turns on (or tries to).
The PSU in the mac II takes between +3V and +6.5V on pin 15 to turn on. Once it turns on, it provides +5V to its self to stay on so you don't need to continue providing power after it spins up.
If the PSU doesn't turn on, the PSU is probably bad.
If the PSU does turn on but the machine doesn't boot, caps are a likely suspect.
If the PSU does turn on and the machine boots fine, it could be batteries, caps, or something else in the switch circuit (the power switch is somewhat complicated, as you can press the power button on the ADB keyboard or the power button, then that eventually sends power from the pram batteries to pin 15 of the PSU).
I recommend using a volt meter to make sure you're only sending the single battery (+3.6V) to pin 15. I've sent the full +7.2V to the pin before with no ill effects, but it's best to be sure.
Be careful though, the pin right next to 15 is -12V. Bad things happen if that is shorted to something when the PSU turns on (or tries to).
The PSU in the mac II takes between +3V and +6.5V on pin 15 to turn on. Once it turns on, it provides +5V to its self to stay on so you don't need to continue providing power after it spins up.
If the PSU doesn't turn on, the PSU is probably bad.
If the PSU does turn on but the machine doesn't boot, caps are a likely suspect.
If the PSU does turn on and the machine boots fine, it could be batteries, caps, or something else in the switch circuit (the power switch is somewhat complicated, as you can press the power button on the ADB keyboard or the power button, then that eventually sends power from the pram batteries to pin 15 of the PSU).