Recently my 2 year old compressor stopped working.It builds pressure in the tank but when I try and turn the black knob on the right hand side to get pressure to the outlet hose, the valve doesn't seem to want to open. I also notice that when attempting to turn the knob that it just doesn't seem to catch, its real easy to turn, then it almost wants to catch and it gives me about 5 psi, then the knob seems to loose grip and spins real easy again and I loose that pressure. All in all though, I get zero pressure to the out let hose that runs to the main regulator. Any ideas out there???