Allen Bradley VFD display problems

[Jim Moser]

This unit runs a Strands 440 v. Gear head drill press 1.5 HP off a step up transformer, I have no reading on the display but unit still works as I have a foot operated start run switch and the ramp up and down I programmed in seem the same. I tried another programming module and I just bought another one off ebay and it also works the same. No display on all three but seems like the same ramp up, don't need to change any programs, just curious why all 3 diplays are dead and worry about future failure as this not a common vfd running off single phase.
Any ideas Y
Jim

 

[JST]

Interconnect cable, or the outlet the cable plugs into, possibly.

Might not be getting the signals the display needs due to bad wire or bad connection at main unit connector..