Good info, thanks!Your photo shows a late model Texas Peripherals drive. There are no drive select jumpers like on the Tandon drives. Drive select is done with pins removed from the flat ribbon cable.
You mentioned the drive cable has good continuity in your original post. If you have a straight through cable using all wires, that's your problem.
Also, a terminating resistor pack is not used on internal drives. It is only used on the last EXTERNAL drive on the system.
it's not straight through, the manual says for Drive 0 pins 12, 14 and 32 should be missing- they are. For drive 1 pins 10, 14 and 32 should be missing- they are. Not that I assumed a problem with the cable as it looks original to the machine, but for the sake of covering all my bases I checked and it looks good to me.