Rehabilitating original x-carve

I have a 2015 x-carve that I used with moderate success throughout 2015/early 2016 before I shifted most of my creative focus to 3D printing and general work/life distractions.
Cut forward to 2019 with a new workshop and some more time to dedicate to hobbies, I fired up the old girl and am currently working through trouble shooting things to get her functioning again.

The first startup caused the motor driver to pop and release its smoke. I assumed dust or corrosion was to blame and purchased a new one.

Having replaced the motor driver, I found that jogging the machine through Easel was giving very limited, and inconsistent success. The Z axis worked reliably, but X and Y would run, appear to get stuck or skip steps (then stop responding to Easel commands).

I figured there was too much resistance in the bearings, and removed the X and Y motors from the frame and found they were still skipping steps and responding intermittently. The gantries move find when pushed by hand, but cleaned and oiled everything anyway and mechanically things are running smoothly.

So I’ve purchased new X and Y motors, and unfortunately I’m still getting very intermittent response from them when I’m trying to jog them from within Easel. I do have the pots cranked up to full power on the motor driver port.

Does anyone have any suggestions on what I should try next? I’m wondering if replacing the wiring would make any difference, or trying a new arduino? I do live in a fairly corrosive environment (coastal Australia).

Thank you anyone who can offer any tips.

Cheers,
Sam

As an update, I’ve tested the stepper motors directly with another arduino and different motor driver and they are working properly (the original ones, and the new ones).

Sounds like it could be a wiring problem. Broken/damaged wires will cause that.

I did try connecting one of the steppers directly to the g-shield with new wires, and interestingly the motor seemed to run smoothly for 5 or 10 seconds, and then bog down, start sticking and skipping steps, and ultimately becoming unresponsive.

Temperature overheat by the sounds of it.
I would suggest you get bigger drivers like TB6600´s which are very cheap and have capacity exceeding your requirements. Get 4, one for each stepper as on a 3 driver setup Y driver feed 2 steppers => serious power lacking.