At 7:44 -0800 11/11/13, Jeff Walther wrote: >On Friday, November 8, 2013 3:19:37 PM UTC-6, Scott Lawrence wrote: > >SCSI Drive does not function either on the internal or external chain >connectors with appropriate terminaton >(doesn't work without termination either... i had to try it. ;) > >SCSI probe complains that the chain is not terminated. > >I'm at a loss at this point. About the only thing I can think of is that the >53c80 SCSI chip is faulty... that seems to be the only place left for a >fault... > >Thoughts?
There is a fuse on the SE/30. F2 or F3. I'm pretty sure one of them is a typical series fuse on the 5 volt terminator power pin in the center of the 50 pin flat cable socket. An ohmmeter with the SCSI disconnected is a quick check. Some disks can also supply 5 volt power. There is often a jumper for that. Two devices supplying terminator power was once a no-no but a series diode easily prevents one device's power from trying to run another set of logic chips. D3 might be such a diode on an SE/30 circuit board. Many little ohmmeters have a diode check option that should read about 0.6 volts across the diode in the forward direction.. -- --> From the U S of A, the only socialist country that refuses to admit it. <-- -- -- ----- 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/ --- You received this message because you are subscribed to the Google Groups "Vintage Macs" group. To unsubscribe from this group and stop receiving emails from it, send an email to vintage-macs+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
