If your previously working setup stops working when you set
Dip Switch 1 to the Open position, then the PMDX-126 is not
seeing the Charge Pump Signal.
There are two ways to confirm the presence of the Charge
Pump signal. First, there is an LED on the PMDX-126 labeled
Outputs Enabled. It you set DIP Switch 1 to On for operation
without a Charge Pump, you should see the LED glow as
long as you do not have an E-Stop condition. If you set
DIP Switch 1 to Off to enable the Charge Pump function, then
this LED will turn off when the board does not see a Charge
Pump signal on Pin 17. You can also look at the Pin 17 LED
beside connector J6 to look at the Charge Pump signal directly.
Your description of the wiring between the VFD and the
PMDX-107 is correct.
If you cannot get the Charge Pump signal to work, you will
need to set DIP Switch 4 of the PMDX-107 to the On position
to tell it to ignore the Charge Pump signal.
You can tell if the PMDX-107 is responding to signals from
the SmoothStepper by looking at the LEDs on the PMDX-107.
If these LEDs are responding and your VFD does not, you
should also try the TEST button on the PMDX-107.
If the VFD still does not respond, it is likely that your
VFD parameters are not set correctly. The most important
ones are A001 (frequency source) and A002 (Run command
source). Both of these must be set to 01 to allow activation
from the control terminals where the PMDX-107 is connected.