Denford Software & Machines

The custom card is used to create the analogue voltage for the spindle speeds & as a power supply.

Yes you can gain access to the X axis drive belt & pulleys relativly easily.

Remove cover plate. (next to the machine bed & fastened on with 4 countersunk allen screws. You may need to remove the rubber matting to gain access to the screws).
Then remove the 4 screws holding the motor plate & gently lift the motor up & off.

You should be able to move the X axis drive pulley by hand easily.

It certainly sounds like stalling, and you may be in a situation with the secret jog mode, where you are stuck at one end, and can only jog the wrong way (ie, further into the end stop)...wherever the axes are on power up, is in effect home or machine Zero. So the secret jog mode will not let you jog both ways because of the software limits

Have now removed the x axis motor.
The x-axis moves freely by rotating the larger pulley.
Tried the x-axis motor on the bench not connected to the pulley and ball screw. The motor behaves the same as before, hunting around not knowing which direction to turn to - and then occasionally will burst into life and turn in the correct direction. This happens in both +ve and -ve directions.
I have swapped the x and y axis cards in the rack with the same result.
Would this be a faulty stepper motor?

Motor, wiring or connections could be faulty.
However, you should be careful diagnosing a stepper motor that has no load on it - they can behave erratically anyway when they don't have any inertia on the shaft - Put some gloves on and hold the motor pulley while jogging it - don't blame me if you hurt yourself though
You should be able to move the axis pulleys by hand as well... ?

It may be something as simple as a pin in the Harting plug on the back of the machine. I would disconnect the connector & check all the pins visually. The male pins often bend but normally can be bent back quite easily.

Exactly!!!!

Not one but 3 pins were bent
They may have been bent when I got the machine or I probably bent them! One of the bent pins went to the x-axis motor - so no wonder the motor did not know where to turn.
Looking at the plug wasn't something I could easily do as the mill was wedged against the workshop wall! Which meant I could not see the pins of the Harting plug.
Bending the pins back means that the mill now homes correctly and all axes are operational.

You guys are stars - your help in calmly solving my various problems (software, Mint and stepper motor) has been invaluable.

Did you notice the donation button we've added (by customer demand) to the main forum screen ?

Well done. I should have thought of the pins earlier but at least we got there.

This is what bent pins on the Harting connector look like.
This caused the errors above and I hope has not caused any other damage! With care the pins bent back to their near original position, though I was somewhat apprehensive at bending them - a broken pin on that connector would not have been welcome!
The mill now works splendidly thanks to the Denford Team ....