It all depends on your LESU and ASR model.
The cable from the TD base to the rear terminal strips (C) has 20-point connector U
The "bare minimum" is to activate the TD clutch magnets...
(C137-U3-clutch_magnets-U5-C136)
They may be operated off 115vac or (with a series resistor) 120vdc
The magnets are connected in series with the manual TD_stop_run switch (C134-U8-switch-U6-C135) and the TD_tape_out switch (C139-U9-switch-U11-C140) - and also probably the SEND-REC switch on the keyboard and the K-KT-T switch (C133-F10-switch-switch-F15-C132)
One schematic showing the clutch magnets using AC is here
One schematic showing the clutch magnets using DC is here
Following all the jumpers on the C terminal strip you will see that the clutch magnets and switches are powered from C132 and C140 - these will be hooked to the AC source or via resistor to the DC source.
Have Fun!