So I bought I second hand machine just set it up and when I use the machine controls and press down on the z button the machine moves up and down and the same when I press the up button, there is no specific pattern, it is random. Has anybody experiened this problem
There is a loose wire on the motor.
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This. Or a bad/broken wire.
Thanks guys just sorted it out
When it was acting up the z axis was making a weird noise, now that it’s fixed it sounds normal, could I have damaged the motor when playing around with the up down controls when wires where loose?
No, steppers are hard to break. You don’t want to connect or disconnect then with the power on, though. That could fry the motor driver.
Just a little more info:
Our steppers have four wires, grouped in two pairs. (one pair for each motor coil)
These are used to pulse steps and direction. (and provide power obviously 
)
With one wire not making contact, the motor will spin/sound as normal but it will loose directional information and simply spin in random direction.