IMac :: Computer Crashes And Loses Hard Drive When Goes Into Sleep Mode?

I just had the original 300 GB hard drive fail in my aluminum 24" inch iMac running the latest update of Leopard. I wasn't able to save it using diskwarrior (diskwarrior said it was some sort of mechanical failure) but I was able to recover most of the data from it by booting from an external hard-drive.

So I went out and purchased a brand new Western Digital Caviar Black 1TB drive. The install went fine, it found the drive partitioned it and installed Leopard successful. Then is crashed and disappeared when I left it alone to run all the software updates. I came back and the computer was stuck on "Restart Required" after downloading all the updates. I went to hit restart now, and the system just hanged, wouldn't do anything. So I hard powered down the system and restarted it. It came up with nothing, just stuck on the White Screen of Death. So I plugged the external drive back in and booted from it. Mac OSX couldn't find the drive and diskwarrior would crash if I tried to run it. I tried to boot up from the OSX start-up disk and it couldn't find the drive either.

So I took the case apart and made sure all the connections were solid and the drive was mounted correctly. Everything looked fine so I plugged it in and it started up fine. Finished the updates and the iMac ran great.

So I thought maybe it was overheating, so I've installed smcfancontrol and started to monitor the temp of the drive. I also took the mac apart again and sucked out any dust in the fans or vents. The drive never goes over a 105 F, so it doesn't seem to be overheating.

However, this is where the problem is consistent: everytime the iMac goes into sleep mode, it crashes and the iMac is unable to find the hard-drive again. Unless I unplug it completely for 5 minutes or so. Once I unplug it, it finds the drive and operates like a champ.

I think maybe there's an issue powering the drive back on? Anyone have any ideas?

And my follow up posting later that day:

Quote:

So I ran some tests just to see if was an overheat issue, hard drive malfunction, or sleep issue. I decided to start encoding a video, pulled up Word, Power Point, Excel, started downloading all 6000 mail messages off my server (I never delete my e-mail :-/), also started installing iLife 09, and pulled up a bunch of webpages in Firefox with multiple tabs.

However, I shut off all sleep mode options on the hard drive. I let it run for an hour and came back. Everything is fine, hard drive isn't locked up and smcfancontrol shows the hard drive running pretty hot (115 degrees) but not so hot I'm worried. So it's definitely something to do the hard drives going into sleep mode and not powering back on. It's also weird that I have to leave the computer completely unplugged for 10-15 minutes before the drive is recognized again.

So turning off sleep seems to be my work-around, however, this shouldn't be a long term solution. I'm worried that there is a bigger issue with the iMac, but I'm not sure what would cause this. I've been a PC guy for years, this was my first Mac, and honestly I don't know enough about the inner workings to narrow this down. I would assume this would have to do with the motherboard in some way? But I'm not sure how you would even test it.