Y-Axis Sticking

[cvk31]

Hello All,

I purchased a Taig Mill about a year ago from a great guy back east that had it set up and running parts.
When I received it it came with all kinds of useful info as well as his Mach3 setup.xml so I plugged her in and was starting to make some parts when my computer took the worst kind of a ********* on me.  It took me a little while to get it rebuilt which included a new motherboard.  Work has been so busy the whole setup has sat in the shop for about the last eight months.
Needless to say getting it fired up again after all this time is like doing it for the first time.  I have Mach3 with the custom setup file and everything seems to be back to square one except a for a weird issue with my Y stepper.  Again,  I had the whole setup working before the PC rebuild so I'm a little stumped.
When I jog the Y axis the stepper makes noise like it is trying to go but it doesn't move.  If I tap the jog over and over it will take off at the correct speed and seems to operate normally, sometimes it'll even let me reverse direction.  I switched the leads from the controller to the steppers and the problem is repeated in the x axis and y works fine so I am pretty sure by process of elimination that this isn't a problem with the stepper.  I am using Keling KL23H276-30-BB steppers.
I do not know how to test this but the sound the stepper makes when it is " jammed up "  sounds like it isn't getting enough power.
If I hold down the arrow key to jog it and give the wheel on the stepper a little twist it will usually take off too.
Any help would be greatly appreciated...

[Tweakie.CNC]

I would be inclined to remove the stepper from its mountings and see if this problem persists under 'no load' conditions.

Tweakie.

[angel tech]

I had a similar problem to this, and it was the parallel lead from the comp to the machine that was at fault.

[cvk31]

I thought it might be the screw binding too so I remove the stepper from the mount and it behaved the same way.  This was before I switched the leads and saw the same problem with the x stepper on the y lead.
I am a mechanical designer and don't know much about testing electronics.  I own a decent multi tester but am unsure how to test the voltage of the wires to the stepper.
Can someone give me some bone head instructions?
Thanks for the help Tweakie and angel tech.

[angel tech]

check the gnd connections on the drives.

[Tweakie.CNC]

Is the stepper making a screeching sound when it is not working ?

Tweakie.

[cvk31]

It's not screaching per say but it is definitely making noise. The sound is probably 50% as loud as if it were working properly.
How do I check the ground?

[Tweakie.CNC]

Just a thought.

Go to config, ports and pins and put a check in the sherline 1/2 pulse mode box. Then try.

Tweakie.

[cvk31]

Tried that, no change.
Now that you mention it I thought that it was strange that the steppers are set at something like 32,800 steps?

[Tweakie.CNC]

Is that steps per inch ?
If it's steps per mm then I think you need to retune your motors from scratch.

Tweakie.