After the speed slows down or rises, it crashes and cannot rise or fall
(1) The oil cylinder sealing ring is aging: replace the sealing ring
(2) The solenoid valve core is severely worn: replace the solenoid valve
(3) The viscosity of the pressure oil decreases: replace the pressure oil
(4) Poor board contact: check the circuit
(5) The main circuit cannot be switched: check the circuit
(6) Solenoid valve stuck: clean the valve body