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the LED’s are at the same intensity. If not, disconnect the motor. The LEDs should now be bright. If
the LEDs are not bright, try replacing the motor. If this does not fix the problem, replace the main
PCB. When doing the LED test if either LED never lights, or only one color lights (red or green
only), unplug the motor from the harness and see if the LEDs change. If they do not, you can as-
sume the main PCB is defective and needs replacing.
8. In addition to watching the LEDs as you step the motor through a cycle, observe its mechanical
performance. Look for some kind of mechanical bind or other defect that interferes with the per-
formance and then fix any that you find.
9.
If the machine cycles through all eight phase states, both the software and the firmware (main
PCB) are in good condition. Look for mechanical issues if the stepper motor is still not working
correctly. Software bugs are possible, but at this point, the issue will probably be a mechanical
bind, or a failure in the stepper motor itself.
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