Fuses check out okay. I get 4.x volts on the termination power line out to the drive (tested with and without a drive on there.)
I didn't do a full cleaning of the board. I will look into that when my tantalums arrive (I put in new electrolytics, but decided that was a bad idea.) I did clean a few areas near one of the data lines, since it showed no connection, but I will do a more thorough cleaning. I'll also re-check continuity to those pins. I have checked all 44pins to (at least one of) their destinations on the board, but i'll re-check this. I will also try out disk utility without a drive in there... (SCSI probe didn't see the drive, but saw the mac on the device list) (I will also track down and try other scsi tools mentioned.) -s (I guess i should post less information next time, as people overlooked details in my post. heh) On Monday, November 11, 2013 3:55:02 PM UTC-5, Doug McNutt wrote: > > 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.
