1. Replug the 4-pin signal cable plug connected to the printer port.
2.Re-plug the ACE Pro 6Pin signal cable.
3.Check if the power cord is plugged in tightly and try restarting ACE Pro.
Check whether the multi-color box is working properly. Re-insert the filament into the feeding hole and observe whether the filament is normally fed into the Teflon tube behind the multi-color box. If the filament is seen to be fed into the Teflon tube and the white light is on, the multi-color box is functioning properly.