Chosen Solution
i have the issue where the #1 LED works but nothing else. I hit the power button and then nothing happens, no more LEDs, no power on, no fan noise, nothing. has anybody got any clue as to why that would be? i have just installed an SSD into the machine and the problems start after that. i have tested the power supply according to several videos on youtube and it seems to be working so don’t think thats the problem.
All the #1 LED tells you is that trickle power is getting to the PSU, not that it is working. First check your connection to the logic board from the power supply. Use a multimeter to test the output. Next replace the power supply. iMac Intel 27" EMC 2309 and 2374 Power Supply Replacement
