JPS SCK screw compressor not loading.

I have a compressor that has recently stopped working. I have checked the following; inlet valve and piston, unloader control - solenoid action and piston condition as well as relief valve condition. I have changed the unloader control piston and suction valve piston in an attempt to narrow down the fault. I have found that i have no pilot air to my suction valve. I have managed to get the compressor loading up by blanking off the relief line and removing unloading piston but keeping the solenoid and control in place. Any help is appreciated.