There are two main reasons for this problem. The first reason is that the pressure relay of the hydraulic system is improperly adjusted, and it has been activated when the foot is tested; the second reason is that a relay in the electrical box The K5 contact is caused by a bad contact. The K5 relay controls a solenoid valve coil, and this solenoid valve controls the high-pressure hydraulic oil to enter the oil cylinder of the press, thereby causing the press to operate. By replacing K5 and adjusting the pressure relay to the secondary pressure of the paper presser, it will act. That is, when the foot pressure is tested, the pressure relay will not be activated. After the adjustment is completed, the top wire will be locked and then try again You will find that the fault still disappears.