40 PIN SCSI To 50 PIN SCSI adapter cable for PB 540 & SCSI2SD

[rickrob]

Is there any reason why a 40 PIN to 50 PIN SCSI adapter cable would not work with a SCSI2SD and a Powerbook 540?

AFAIK, Both are SE SCSI.  I looked at the pinouts of the 40 pin connector on the IBM drive and a 50 pin SCSI interface and made this table. I'm thinking of putting something together and giving it a try. I would match up these pins plus make sure all the grounds are there on the 50 PIN side. There are 4 pins on the 40 pin side with +5V, so I could power the SCSI2SD with those.

I'm not sure what I should do with TERMPWR on the 40 Pin side.

I'm think of using the 90 degree PC mount connectors with 2 rows of pins on a perf board and then just wire this up. That will connect to the ribbon cable in the PB and I can use a 50 pin ribbon cable to connect the SCSI2SD.

 

[NJRoadfan]

Pin 26 on the 50-pin port should be TERM POWER. The Powerbook's TERM POWER line might not supply any power to the internal drive, so verify that first. If that is the case, wire term power (pin 26 on the SCSI2SD side) to +5v (on the powerbook cable) to power the SCSI2SD. You might need a diode on the connection.