a4988 move the stepper motor while brushed motor turn on


I have two a4988 motor controller and one a4983 voltage regulator motor controller. When i turned on the power supply of the board. three of the stepper motor is on hold and i am able to control it using PC through parallel port.

But when i turned on the router which is brushed motor. Both stepper motor attached to the a4988 motor controller start to move itself while stepper motor connected to a4983 motor controller remain still. Both a4988 motor controller were connected to a LM7805 voltage regulator which intake of 30V voltage supply while a4983 uses it’s internal voltage regulator.

I have applied 2 capacitor (0.1uf and 470uf in parallel) filtering on all the VCC input of both a4988 and the result is still the same.

Anyone encounter this issue before?


Can you provide a schematic of your wiring and a picture of your setup? We might be able to notice something.

- Ryan