Troubleshooting the PCNC 440 PCNC440 estop and communication issues starts with observing the PathPilot Status indicators.
Shown below are 4 typical conditions, plus normal operation. I provide conditions that can cause the indicators status, and things to check.
All of these requires removal of the electrical cabinet cover. The operator will need access to the rear of the mill.
The MX3660 controller typically has three green LEDs continuously lit when the 48 VDC supply is energized. The three red LEDs will flash if the C1 contactor is not energized, or wires 303 and 304 are not connected through one of the contact sets of C1.
See my video on the power up sequence of the PCNC 440.Tormach PCNC 440 Electrical Operation and Troubleshooting. You should be able to isolate the issue quite quickly.
https://www.youtube.com/watch?v=yiRP1juM5ZY