Is there any additional load added to the machine, circuit, firmware, BLtouch installed, etc.? If so, please restore it to the factory state. 2. Please try to update the motherboard firmware in the link below: Update method: Put the firmware into the formatted memory card, plug it into the machine and turn it on, the machine will update automatically. 3. Please measure whether the motherboard driver is normal. Set the multimeter to DC gear. Place the positive pole on the pin pointed by the red arrow and the negative pole on the pin pointed by the black arrow, and test whether the voltage of each pin is about 24v. Test video available. 4. Measure whether the resistance of the motor is normal. Test the resistance values of the two pairs of pins pointed to by the red arrow and the green arrow in the figure below. The resistance value will be accurate after the multimeter reading stabilizes. Please wait for the multimeter reading to stabilize.