Carette Problem?

At about 65hrs my Carette started making a kind of “chirping” sound when under load. It still build pressure fine and fill times are unchanged but this new sound becoming louder and more frequent. I’ve heard that Joe isn’t much help with diagnosis or repair. I’ve also heard that Bosun (?) has helped some Carette owners but I don’t have any contact info on him. Anyone have any ideas? Uj
 
Thanks all! I tightened the drive belt a bit and the chirp stopped. I also took the alpha filter apart to check the cartridge and saw some rust around the male intake foster. The female end was very rusty. They both appeared to be stainless but rusted none the less? Replaced both. I’ve always used soap water to check for air leaks but it looks like I’ll have to use something else. Uj