Thanks for the responses. Although I can't explicitly check the SCSI cable, the timing of the failure given that the hard drive had previously been working is suspicious, so I'm thinking the hard drive is the likely culprit in this case.

As far as a replacement drive is concerned, as long as it is 50-pin SCSI it doesn't matter from the machine's perspective what hard drive I get, right? I'd be inclined to get a more up-to-date hard drive, but are there any considerations to take into account with that (e.g., issues with sizes larger than 4 GB)? Any recommended brands or specific drives?