Help please. Dip switches and mach 3 settings

[john swift]

great to see you have it working even if your not 100% sure which connection you re-made during your investigation

your connection to the VFD looks correct

in practice using the 12V supply probably will work

while the LM317's data sheet gives the minimum supply voltage as V out +3V this will be the worse case accounting for the production spread in the IC's parameters

even if the supply is too low for the regulator to regulate the output as intended

the fact you have a regulated 12V supply
the voltage is likely to be near to 10V and not change too much and
cause the calibration of analogue control voltage to the VFD to vary

John