My iMac won't power on at all and I suspect the power supply is the issue. I've searched everywhere I can think of, but no one has a tutorial on how to check it on this particular model. I was able to disassemble it without any trouble and I removed and inspected the power supply visually, but I'm hoping someone has advice on how to test it with a multimeter. I haven't been able to find any pinout or voltage information for it. Maybe the same unit is used in other models? Any help would be greatly appreciated.