Replaced Logic board and fan... still same problem, won't boot

[lukenorris]

I ordered a new logic board and installed it this afternoon. I was in the middle of installing snow leopard when the computer shut down. Long story short, I found the fan was dead. I replaced with one from another computer. I now can't get 2 seconds past the apple logo. What could be the problem?

I've tried starting with the battery out and with it in. Trying different ram from other computers I know are good.

I booted in safe mode. I got all the way to the login screen. The keyboard wouldn't type, and then the computer shut down. I had to hold the shift key down all the way to the login screen.

Battery seems good. Held full charge over a week.

I tried the hardware test by hold the D button down. I am not sure if it worked or not. I never saw a report.

 

[ibuyufo]

I ordered a new logic board and installed it this afternoon. I was in the middle of installing snow leopard when the computer shut down. Long story short, I found the fan was dead. I replaced with one from another computer. I now can't get 2 seconds past the apple logo. What could be the problem?

I've tried starting with the battery out and with it in. Trying different ram from other computers I know are good.

I booted in safe mode. I got all the way to the login screen. The keyboard wouldn't type, and then the computer shut down. I had to hold the shift key down all the way to the login screen.

Battery seems good. Held full charge over a week.

I tried the hardware test by hold the D button down. I am not sure if it worked or not. I never saw a report.

When you replaced the fan or when you put everything back, did you put thermal paste on the cpu, gpu and associated heatsinks?

 

[lukenorris]

When you replaced the fan or when you put everything back, did you put thermal paste on the cpu, gpu and associated heatsinks?

I put paste on it new. I am not sure I put enough. But I got it covered with not too much. I thought out of the box apple put on too much.

I don't have the original disk, so I can't try to boot to DVD. I tried to do the hardware test, but it didn't work. The computer starting making a buzzing noise when I held the D key down too long. Then shut off.

 

[eljanitor]

If the fan wasn't working when you installed the new board, you may have fried the CPU.

 

[lukenorris]

would the computer shut down to prevent this from happening? Seems very odd to me that apple wouldn't have this in their safety set up.

If the fan wasn't working when you installed the new board, you may have fried the CPU.

 

[ibuyufo]

would the computer shut down to prevent this from happening? Seems very odd to me that apple wouldn't have this in their safety set up.

Yes, all CPUs will shut down when it reaches a certain temperature point to prevent damage.

 

[eljanitor]

would the computer shut down to prevent this from happening? Seems very odd to me that apple wouldn't have this in their safety set up.

See I thought so too, until I worked at an Apple repair shop. The lead tech there told me one day that sometimes you can fry the CPU, or the video processor even after the fact that the board powers down from over heating. He was a very reliable source of information.

The other thing here is this. I've NEVER known Apple to issue a logic board to a customer as a DIY repair. Usually you can buy a logic board off of ebay, or some 3rd party reseller for a DIY repair. However when you do that you have no guarantee if the board is actually in god working condition, and it only takes a little handling it without an antistatic strap and protection to fry a good board anyways.

Did you use ESD protection every second of the repair? ( ESD wrist strap, and mat?) Was it shipped to you in an antistatic bag?