Scsi to Usb


I have a scsi adapter -- microtech -- that I use to use with great success to connect my old Ibook (OS 9.1) to an external glyph hard drive. I use the hard drive to store sound tracks generated through a much older but still functional Mac quad 800. But now I am using a new powerbook (OS 10.4) and I am having difficulty getting the powerbook to recognize the external hard drive. Any suggestions?