My compressor is making noise. Any help?

Hey,

I got a 2 year old Paasche D200 compressor.  I use it on average 2 hours in the course of a week.  Recently, the compressor has been making an grinding type of noise intermittently during use.  Sometimes I hear it, sometimes I don't.  The only recommendation the manual makes is to return it to Paasche.  The compressor is no longer covered under warranty.  I don't it's worth paying for shipping and repair on a $100 compressor.

Does anyone have an idea of what's going on with the compressor and maybe how to fix it myself?

Thanks,

Jesse