Power supply does not come on, or does not come on every time. If it does come on it will stay working untill it is turned off.
In the start-up circuit there are two 200 ohm resistors in parallel, to form one higher power resistor of 100 ohm. Even that is not powerful enough and it blows often.
This is an always-on 185w power supply that supplies 12 volts only.
The output plug has two grey wires for the +12 volt and two black wires for ground.
The remaining brown wire signals to the motherboard when the output is stable so that the Mac does not come on befor the power supply stabilises. Contary to popular belief this is NOT a signal wire to turn the power suppy on and off.
ATTENTION! This power supply is not designed to be run without a load. So always load it when testing. If not you will blow it up as fast as you can repair it...
How to repair an Apple power supply 614-0363 Celetronix 185w