This is a 5hp unit that I bought new, but is now a few years old. Just stopped working altogether with no warning. Checked continuity on the fuse (20A 320V), it's good. Pump piston moves freely, belt is good. Motor turns smoothly, removed brushes and they look good. Contacts on contactor not burned. It appears that the "contactor" or pressure-sensitive switch is not working. Seems like a somewhat sophisticated device, with a diaphragm and spring-loaded piston which apparently switches the motor on/off depending on the pressure in the tank. There's also a tube from the tank with a tiny pin that pops in/out depending on the pressure. Is this component replaceable? Or can I adjust it? It has a security-type bolt (torx with an "o" in the middle) that seems like it would affect the position of the spring-loaded piston. It's a shame - everything else is in good condition.

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