problem reading external hd

When I took my new (OS X v. 10.5.4) MacBook to the local Apple Store to fix a broken power switch (had deck replaced), two men on the genius desk told me I could make a good external drive by buying an internal drive and case, and that once they were assembled and the drive was turned on and plugged in to the USB port, Time Machine would automatically take over and start backing up my files.

On their advice I bought a case through NewEgg and a Seagate (Serial ATA) 3.5" drive, assembled them and hooked them up. The drive runs, but the computer only partially recognizes it. It shows up on the system profiler, but nowhere else, (for instance, not on the finder window under "devices"). Time Machine could care less about it. When I open Time Machine and it says choose backup disk, no disk shows up in the window.

Is there a setting I have wrong? I have no reason to believe the drive is faulty, and do not believe I need a driver with OS X v. 10.5.4 (if so, where do I go to download it? Apple? Seagate?

Time Machine can use any drive provided it's formatted as HFS+. Make sure the drive is correctly formatted and that you have assembled everything correctly. Also make sure the external case you purchased is for SATA and not for PATA. Some external cases are advertised as being compatible with both SATA and PATA but will have a different internal connection.

Regards.

Thanks, chscag. It's the right case (SATA), and all connections seem to work fine (i.e., it has power -- I hear a friendly hum when I power it up), and It turns up on Disk Utility, though the buttons (repair, verify, etc.) are all grayed out.

How do I format that drive as HFS+? All the software that came with it seems to be for Windows SE and earlier.

What happens in disk utility when you go in to the partitions screen, does it give you any options there?

I get Five Options:
MAC OS Extended (journaled)
MAC OS Extended
MAC OS Extended (Case Sensitive, journaled)
Free Space

I just clicked on the first option in the partitition screen (one partition, MAC OS Extended, journaled), and Bingo! Time Machine kicked in. But (you can tell how ignorant I am of the terminology), was this the right option? I have no idea how it relates to HFS or any other format, or what the various options get me.

Anyway, thanks for steering me to the partition window. I look forward to learning what I got.

You got it spot on, that's the best format for Time Machine

Many thanks.

Incidentally, that was good (and economical) advice I got from those disloyal Apple employees who steered me away from their company's products. The Seagate drives come with a 5 year warranty; I got a 160 Gb drive which is ample for my needs (mostly writing, a few photos, no videos or music) for $35, and a case (Galaxy) for $20. Very quiet, doesn't seem to get hot. Only drawback is a very short USB cable.