Ryobi 920 delivery table wont go down whilst in production

Hi, My ryobi 920 offset printing machine delivery table wont go down whilst in production. I checked all circut boards and scencors at delivery, all working fine.
Any advice please

 

Have you power at the motor when the sensor is activated?

 

Test the sensors or limit switchs for ;1) Lack of voltage 2) loose or break wires 3) dirty 4) Faulty sensor.