2 iMac LED Diagnostic- logic board just replaced
iMac was dead- old logic board had no diagnostic LEDs. Apple store said needed new logic board a year ago (said they tried a new PS and no go).
Just put in a new logic board. LED#1 lights up, but power button does nothing. No sounds, no fans, no HDD. I did add a SSD as a secondary device.
There is another LED on right side that comes on/off when power button pressed (below DVD player).
Could it be the power supply? Anything else?
this is an iMac Intel 21.5” EMC 2428
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Thanks. I’ll try that. I’m also wondering if I burned something up. When I first powered on the new board, I got a distinct plastic- burning smell and unplugged it. I hadn’t put the LCD or RAM back on yet. Haven’t smelled it again in the 10 times I’ve plugged it back in to test though.
Well, I took everything apart again, looked at both sides of the logic board with a magnifying glass. Didn't see any 'burned' areas but I don't really know what to look for.
by Skot Smith
If it something that you did smell you most likely would see it as well :-) Could have been just the board firing up for the first time ;-)
by oldturkey03