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x13gamer

macrumors regular
Original poster
Oct 27, 2006
220
34
Pure Michigan
When I press the start up button, while the Start-Up button is pressed, the internal light will remain on while the button is pressed. The fan will kick on for about 3 seconds and then the fan will shut down and the computer will still be off. Is it my power supply or logic board? I have reset the PRAM. changed the ram, switched the processor and changed the battery. Could it be anything else?
 
It is really kind of hard to diagnose such problems over the internet. You'll probably have better luck taking it to a mac specialist.
 
I know you posted this before, but we never heard back. If you did I would then suggest you replace the power supply since it's cheaper then the logic board.
 
When I press the start up button, while the Start-Up button is pressed, the internal light will remain on while the button is pressed. The fan will kick on for about 3 seconds and then the fan will shut down and the computer will still be off. Is it my power supply or logic board? I have reset the PRAM. changed the ram, switched the processor and changed the battery. Could it be anything else?

If it is the logic board, it is more likely you would get some sort of feedback, though it would vary depending on the model. On older Macs, they would make the sound of car tires screeching then crashing ("Screech of death," I think it was called). Not sure what new Macs do.

It does seem like something in the power circuitry is more likely the cause. Have you reset the Power Management Unit (again, varies by model, so can't make more specific recommendations). You could also try using a different power cord and plugging it into a different outlet. If all of those fail, then yes, I'd agree the replacing the power supply would probably be the cheapest next step. (Or take it in to someone with a power supply tester and a logic board tester :) ).
 
It MAY be the logic board, if you are very unlucky.

The same thing happened to my MacBook when it was Liquid Damaged, and it seemed to be the logic board.

Get it checked out, thats your best bet, and fingers crossed that it won't be!
 
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