Thread: air compressor fix

I have a husky(or something like that) 30gallon stand up air compressor--had it plugged in and filling up yesterday and the control knob (the one you set your PSI output with) popped. It has a separate relief valve so this wasn't suppose to happen and seems like the threads on the knob stripped? i can push it in and turn and it acts like it wants to catch a thread but it won't. How do you fix this? Do you change the entire regulating assy or can you take it apart and just replace the knob?