I seem to recall that the Mac Plus does not supply Termination Power in its 25-pin SCSI connector, and thus relies on the attached hard drive(s) to supply that signal to the SCSI cable daisy-chain. Later Macs had that Termination Power activated in their SCSI connectors.
Without Termination Power, any SCSI terminators on the daisy-chain are useless, and drives "disappear". :-) ----- Original Message ----- From: "anthonyschr" <anthonys...@gmail.com> To: "Vintage Macs" <vintage-macs@googlegroups.com> Sent: Saturday, November 19, 2011 9:15 PM Subject: Re: My Mac Plus hates SCSI Drives… > Hey, thank you for asking! I've had problems with SCSI on a Macintosh > Plus, and I'd like to know what's wrong. I have access to a > PocketHammer525FMF (a little over half a gigabyte) and a PowerUser > drive that reads ~270 Mb hard disk cartridges. I've been able fairly > often to mount and use the PowerUser drive on the Plus, though rarely > managed to boot from it. The PocketHammer has never mounted, though it > works alright on a PowerBook 170. -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to vintage-macs@googlegroups.com To leave this group, send email to vintage-macs+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/