The terminator that Apokalipse is refering to is an active terminator - looks like a black plastic rectangle normally that is either hardwired to the cable or plugs in to the end of the cable.
But this is normally only necessary for use with 68pin scsi. Older 50 pin doesn't really require it BUT both types of drive must have their termination jumper (on rear or underside of drive) enabled if they are the last device, or only device, on the chain.
If you have got a 68pin drive, then the scsi card itself should have a bios chip (ie be bootable). So in fact are some 50 pin cards also. If so, it should display the cards make/model on screen just after the normal post test. It should also give you the option to enter the scsi bios settings.
If it does, then do this & see if the drive is being detected in the scsi bios