MKII SCSI Mod.

[Zac67]

Looks very much like active termination - passive ones do not work by setting a jumper, instead you'd remove the resistor arrays.

[Zac67]

Hate to be {bleep}in', but
- trying to deactivate a passive terminator pack just by disconnecting GND is no good idea - and probably not very stable either. You'd have to disconnect 5V, too, and still have the data lines loaded with floating resistors
- the BBoAH Pic clearly shows two UC5603DP active termination chips

[Zac67]

The floating resistors would more or less just put a load on the bus - with only a few devices that might be forgivable but I wouldn't really try. But I've never seen passive terminators that could be disabled with a jumper.

Your termination schemes are correct, without the backplane board you'd still have to terminate both ends of the SCSI chain - if only one host adapter connector is used, the other needs some kind of terminator.

I usually disable all passive terminators I find and replace them with active ones, that can be switched much easier.