4th LED on logicboard is not on
I am experiencing the same issue, at first the iMac froze and then i proceeded to shut it off. Then, I turned it back on and there was no chime, picture, or even a back light from the LCD but I could hear the fans and drive spin up. I took the iMac apart and checked out the LED's the first LED lit up after plugging it in, the second lit up after turning it on and then the third one turned on shortly afterwards, then they all turned off and then came back on again.... but the fourth never lit up at all during this process. I would assume the logicboard is at fault due to the nature of it not giving me any visuals and or post chime. I know that sometimes when PSU's go bad the internal fans and drives can still turn on if they are operating on a separate rail. It's either of the two I just cant figure out which one.
HELP!
Is this a good question?
2 Comments
Well it turned out that my lcd screen was fine. My last resort was the power supply which turned out to be the problem. That in turn took out the logicboard. In the end it was the power supply and logicboard that failed. I have read about this problem on other sites and seems to be one of the more common failure points.
I am not an expert enough to suggest that this is your problem, but it sounds awfully similar.
by Eric S
I am at least getting power and the first and second LED's lit... But I just cant figure it out.
by Gill