Check that all four wires on the stepper motor are properly connected and that the current limiting potentiometers on the A4988 drivers are set correctly.
The Spindle connector is typically labeled as SPINDLE . Ensure you maintain correct polarity to avoid reversing motor direction. 3. Laser/TTL Module annoy tools cnc board manual pdf
Download and install the CH340 driver . Try a different USB port and use a short, shielded USB data cable. Issue 2: Stepper motors make a grinding noise or skip steps Check that all four wires on the stepper