[Digitalcarnage]

Ok, so a while back, I picked up an a1278 unibody pro, that was broken.(for fun I buy broken apples, fix them and resell them) I decided I was going to keep this one for myself, and set it aside and finally have had some spare time to start working on it.

Anyhow, everything appears to be in working order, but when powered up, the screen stays black, the sleep led stays brightly lit(no flashing or dimming), the disc drive spins up.

I have tried removing ram, changing slots and dimms(don't have any other compatable cards at the moment), I can successfully, or as far as I can tell, reset the pram and the smc but doesn't change anything. The battery takes and holds a full charge, and the computer will stay on until I shut it down or the battery dies. Connected an external monitor, and nothing.

Haven't tried target disc mode to see if maybe it does have access to the hd still as I don't have a FireWire 800 cable at the moment.

Not sure if there's anything else I might be overlooking, and I've tried everything I can find through searches. But before I replace the motherboard is there anything else I should look into?

Also, the nearest apple store is a few hour drive, and trying to get there has been out of the question with my schedule lately.

Thanks for any info!

[Waragainstsleep]

Well the LED being on suggests that the motherboard is not able to communicate with the display. You need to verify that the disk has an OS and will boot before writing the board off. If the disk looks ok, then its probably the board.

I would suggest pulling the drive and testing it in another Mac or pulling the drive and then trying to boot from a DVD or USB disk. Then try the external display.

[Digitalcarnage]

Ok, I have tried booting it without the hd installed, but I can't recall if I had stuck my osx DVD in yet or not. But I will try the external display this afternoon/stick the hd in my brothers MacBook.

[Digitalcarnage]

So turning it on with no hd installed made the led not come on, but the screen, nor the external, showed anything. Putting th hd in my brothers computer, it turned on, chimed, and went no further. Putting my brothers hd in mine, changed nothing except making the led come back on.

[Digitalcarnage]

Nevermind, my hd did boot up on his computer.

[Digitalcarnage]

Also, not sure if it makes a difference, but just noticed that if I slowly close the lid, the led gets dimmer, until it's shut and it gets extremely bright again.

[Waragainstsleep]

The dimming LED is a sign of a bad board if memory serves.