I dug up the wiring diagrams for the 28ASR with sync pulse magnet.

It turns out to be easy to get it to do what we want...

You can ALWAYS ENABLE the sync pulse magnet to run off the internal 120vdc supply.

Then the K-KT-T switch will disable the magnet in T mode so that the perf/reperf can be driven off the keyboard without the keyboard transmitting.

Ref: Note 15 on the actual WD and note 8 on the schematic WD

Check that the following jumpers are in place

C125-C142-C22 (-120v)

C124-C131-C21 (+120v)

Connect a 2000 ohm 10w resistor between C126 and C125 (this limits the magnet current to 50ma)

Move the magnet hold-down lever out of the way.

It works!

Have Fun!