Is the hydraulic pump running? Power down and then power on again. Push POWER ON again and test. See hydraulic troubleshooting and repair for more information.
Is there no hydraulic pressure on the adjustment valve? Check the dial again, set the pressure higher.
Is the foot switch working? Check the input signal of the foot switch on the diagnostic screen (X-input). If the input is not OK, check the footswitch contacts and cable connections. The wire could be broke, the wire terminal could be corroded. Check the foot pedal, can you press it all the way down? - or there is a chip under it?
If the input is OK, check the PLC output to the solenoid in the ladder. If the PLC output is not made after the foot switch operation, follow the ladder to determine what logic is needed to turn on the output coil.
Is the chuck working by the MDI M-code command? If the chuck is working with M-code, but not with the foot switch, check the foot switch.
Is the output of the solenoid OK? If yes, it could be a broken wire at the connector of the solenoid, the connector could be loose, or the wire of the coil could be broken. Swap the electrical connector for the coil to the other side or coil to see if coil energizes.
Is the draw tube, which connects the hydraulic cylinder and the chuck, not working? The tube could be unscrewed from the cylinder or the chuck. Also check the chuck body, especially the internal wedge, which should be greased up on a regular schedule. If the chuck is dirty or not greased inside, then the draw tube can't operate the chuck in a full extend.