My SE/30 SCSi problem has been fixed!! The via connecting pin 25 of the SCSI chip to pin 9 of the SWIM chip was corroded by leaked capacitor fluids and was no longer conducting. I formed a solder bridge over the top of it after exposing the surfaces of the connecting traces and Voila! the system booted off the hard drive like a champ. This repair also fixed the sound problem I was having (low volume and truncated startup sound). Thanks for all the advice and help provided by group members.
In diagnosing this problem, I creatged an expanded version of a previously submitted schematic of the SCSI pin connections. This expanded scshematic depicts each of the chips that connects to the SCSI chip (with their respective pinouts) in the same orientation as they are mounted on the MOBO. This allowed me to rapidly check continuity paths for each of the SCSI pins to identify the path that was broken (open circuit). If anyone would like a copy let me know and I'll forward a JPEG image.
In diagnosing this problem, I creatged an expanded version of a previously submitted schematic of the SCSI pin connections. This expanded scshematic depicts each of the chips that connects to the SCSI chip (with their respective pinouts) in the same orientation as they are mounted on the MOBO. This allowed me to rapidly check continuity paths for each of the SCSI pins to identify the path that was broken (open circuit). If anyone would like a copy let me know and I'll forward a JPEG image.