Chosen Solution
My iMac 27” has been randomly restarting and kernel panicking for a week, as well as getting hotter. It boots on an external ssd connected to one of the thunderbolts ports since the internal drive died. Now, after a final restart, it does not boot anymore : the external drive’s led lights up, the fans rotate the cpu seems to warm up, but no chime and the display remains black. I also checked on the network and with Remote Desktop : nada. I.e. the Mac does not boot. I’m thinking power supply or graphic card… I did a hardware test last week and there was no problem ;except for the internal HD. Any insight ? Thanks Sergeï
Observe the diagnostic LEDs on the logic board. If just #1 is lit, change the power supply. If 3 LEDs are lit, go for the video board.
