Not seeing the internal HHD, but will see a firewire HHD

Question

I know there have been some similar topics along this line, but my situation appears a bit different.
History: I recently purchased a used 15" Powerbook Titanium (1.5GHz). It had an OS install issue when I purchased it, but for $200 I figured I'd try it. The problem is that it doesn't see the internal HHD when you try to install the OS. It boots fine (good tone when started), and reads the install DVD just fine also. During the initial portion of the OS installation attempt, I use the Disk Utility to try and reformat the installed HHD, but the HHD isn't seen by the system so I can't proceed. Additionally, just to be sure, I've swapped out the first HHD with a known GOOD one, but the results are the same. It's not seen by the system.
Anyway, after reading a number of posts with similar problems like this, in one of them it was suggested that the user try using a firewire drive. So I did the same and set up a Firewire enclosure. I used the desktop HHD out of my MDD Dual 1.25GHz, just to see if it would work. This drive is already loaded with OS 10.5.6. The Firewire drive "WAS" seen by the system. So before rebooting, I went to the "Utilities", and selected the Firewire drive to be the "BOOT" drive and BINGO, the system booted using this drive without a problem at all.
My questions on are this:
1) What is the probable cause for my system not seeing the internal drive? Damaged cable? Disk controller bad?
2) Could the Motherboard be bad? It seems to work OK, and everything is running from just fine from the firewire drive. Also, the motherboard passes the Apple start up Diagnostics test without any issues.
Any thoughts or ideas about what else to do, or additional checks to make, would be greatly appreciated.
Thanks!
Rudy

Answer 1

It's encouraging that the drive spins up. On the thread with the 12" PB with a faulty ATA bus, it didn't.
To be absolutely clear, you are booting from the installation disc, and then navigating to Disk Utility on the installation disc? And you say that the hard drive cannot be seen at all with the Disk Utility on the installation disc? And that is why you cannot proceed to reformat it?
In case it would be useful, look over Kappy's Extended hard drive preparation:
http://discussions.apple.com/thread.jspa?threadID=1885474&tstart=60
You may want to take a careful look at the cable and see if you see any breaks in it or anything like that. You also want to be sure to replace any kapton tape with a fresh piece.
I'm hoping that it is not the ATA bus, as I don't know of a way to fix that.
Good luck!