Chosen Solution
Hi I have an iMac that is dead after a thunder. Now the power supply seems ok, measures 12V and 2V on it, and I ordered another one, as Led #1 do not light up at all. This situation is not described in LED diagnostic order sequence (unless it is the power supply to logic board cable, which I sincerely doubt). Power supply is singing quietly, other than that there is no reaction to power or power switch. any ideas? Is there anywhere in logic board I can follow the 12V or the 2V to understand why LED1 is not on? Kristoffer
I would proceed with getting a new PSU. Most of the times, when the voltage spikes without a surge protector between the outlet and the iMac the power supply is fried. You said it was singing quietly, which normally means that there is a voltage leakage somewhere on the board. If that is not the case, it may have been strong enough to get through to the logic board and cause damage there, but in most cases that is unlikely. Try the new PSU, and if that doesn’t work, then it is most likely a dead logic board, in which case, it may be cheaper to get a new iMac, rather than replacing most of this one, and instead selling it as parts to someone who works with these types of computers. Hopefully the new PSU will work! Hope this Helps
