Check how much RAM the Apple IIGS has: to support the High Speed SCSI card,
an Apple IIGS must have a minimum of 768K.
Also, check DIP switch 8 on the CMS drive. It controls the reset line,
which is pin 40. All Apple SCSI cards use the reset line for handshaking.
If this pin is disconnected or turned off, the Apple IIGS won't recognize
the hard drive. Be sure that switch 8 on the CMS hard drive is in the
closed position.
If switch 8 is in the closed position and you still do not get recognition
of the hard drive, check the SCSI switch to make sure it is not set to 7.