I live in San Diego, and I have a C28 with a problem in the low-level inputs. One channel is out completely, and the other has a lot of static. I have taken it back to one repair organization three times. It works for a couple of days, and then starts to resume its bad behavior. Any advice on what is wrong? Is there a service center in San Diego where the technician will talk with client? The place I have used will not divulge any information. Thank you.