I have an old RCA D77 that I use for voice overs, female vocalists (especially of the jazz kind), male vocalists when I'm looking for a classic vibe, brass and also clean guitar cabinets (although I started getting paranoid about a blast of air from the amp blowing out the ribbon and I quit that).

Lately the mic has developed a buzz (hum?) and although Im pretty sure its the cable am thinking this old guy (we call him Otis)
its about due for a trip for service, after all he is already like 60 yrs old. 8)

My question is, for you knowlegeable acoustic recording musicians, what is a good place to take Otis to and do him justice? I'm in the LA area and would rather take him in person and talk to the tech myself. We are talking about a really especial old guy here. :D

thanks