CNC Bridgeport Mach 3 Issue

We are running a Retrofit CNC Bridgeport that’s a bit of a Frankenstein.

We have a Windows XP PC Running Mach 3.

The Steppers are controlled with an old Flashcut “BlackBox” made by Anaheim Automation that’s just the Stepper Controller. It’s a serial port connection.

Also, the Serial Cable has been modified to allow Mach 3 to control the black box instead of the FlashCut CNC Controller it probably originally came with.

Today we disconnected all the wires, the PC, Steppers, everything, to clean behind the machine and do some wire management.

When we reconnected everything, Mach 3 no longer moves the steppers. The DRO in Mach 3 moves but the steppers don’t.

The stepper controller has 3 green lights on for each axis (no red fault lights) so I think the black box is fine.

Nothing in the Mach 3 settings were changed so I don’t think it’s Mach 3.

Which only leaves (in my mind) the PC Serial Port, and the modified Serial Cable as potential culprits. When I go into the Device Manager in Windows the LP1 port (I think) is functioning correctly according to windows. We did a continuity test for the pins in the serial cable and no breaks were detected.

Which only leaves (in my mind) ???

If anyone has any ideas, please post them. Tough part of the season to lose the CNC mill. Thanks in advance.


I know you did a continuity test to make sure there were no breaks from one side of the cable to the other, but any chance you tried a continuity test between pins to make sure nothings shorted that way?

I would suspect COM port settings not being correct in Windows. Was the PC on when you made the disconnection, or was it all powered down? Any chance you have the previous COM port settings documented somewhere? Or a HDD backup?

LP are generally parallel ports. They use the same 25 pin connector as a serial port. Are you sure it is plugged into the correct port?

Thanks everyone for your responses so far.

I’ll check for shorts between the pins Rich.

I’m used to the COM port sometimes being an issue with the USB driven CNC machines we have, but I think the Parallel Port settings are default in Mach3 and Windows.

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