You may want to see my MultiMode wiring summary.
The manual stepper switch is a double pole double throw (DPDT) switch. I've labeled the contacts below
In my MultiMode, the switch contacts are wired as follows:
- Contacts 1, 4, and 6 are shorted together, and fed by a white-brown striped wire,
- Contact 2 is a purple wire,
- Contact 3 is a black wire, and
- Contact 5 is a grey wire.
Using a multimeter to measure the average voltages I got:
| Wire | Up | Down | Off | Role | Main | DB-25 |
|---|---|---|---|---|---|---|
| Black | 0.2V | 0.2V | 0.0V | Ground | UL+4 | none |
| Purple | 5.0V | 0.2V | 0.0V | Direction | UL+5 | none |
| Grey | 5.0V | 5.0V | 0.0V | Enable | LL+6 | none |
| White | 5.0V | 5.0V | 5.0V | Power | UL+6 | 3 |
So the white and black wires carry power and ground to the switch, and the purple and grey wires carry the switch information back to the electronics. The 'Main' column records the line's lead on the main circuit board in the MultiMode, and the 'DB-25' column records the line's lead on the DB-25 cable to the NanoScope controller.
From the main-connector, the grey and purple lines start spreading out, ending up at (partial list):
- H7555IBA, a CMOS clock.
- NCAFMJM, a top-secret something-or-other.
My guess is that the grey enable-wire from the switch turns on the H7555 timer, and the NCAFMJM is a stepper driver chip, which receives a direction input (the purple wire) and a pulse-to-step input (the H7555 output). The output of the NCAFMJM heads over to a DS3658N current driver which drives the motor.