PSU Issues Testing Troubleshooting.
Good morning everyone. I bought an iMac project. I was aware that the computer had issues when I bought it, but I like a challenge. The issue is, it doesn't power on really. If you press the power button, you may be lucky and get a blurb of the Mac start up chime, but it gets cut short. There's no response from a screen and resetting PRAM/SMC hasn't done anything. So I opened up the iMac. When the power button is pressed, the fans start trying. Then they stop. Then each fan, one by one, goes then stops. I have located the diagnostic LEDs on the board, and they've helped. LED 1 is on, indicating trickle voltage is present. When the power button is pressed, LED 2 flashes while the fans do their thing, then once that cycle is complete it remains off. So! I have the PSU removed, and have searched high and low to see if there's a good way to troubleshoot it. There doesn't appear to be a good reference to what the pinouts and their voltages are. Also, do you guys thing the power supply is at fault, or the Logic Board? The Mac is obviously trying.
Thanks for your time!
Is this a good question?