Hi TroyO

after looking at the boards circuit diagram and the IC data sheet

with no step/clock (pin21) pulses being received by the stepper IC ,
the IC pin 25 should be switched to ground
this connects R13 a 2K2 resistor in parallel with VR1 the 5K potentiometer and R 12 ( 470 ohms )

the extra current that now flows through R4 (2K7) the maximum V ref will be 1.84 V

as soon as the IC receives step pulses pin 25 should go open circuit
and the maximum V ref will increase to 3.35 V

John