The Sound Well in Berkeley no longer does repairs much, they recommend:
Gene's Sound Service 415-377-1258
House Calls only, based in San Francisco but works most of the Bay Area. He does charge for travel time but in our opinion is very reasonable. He will fix a lot of things most of us won't touch and we are amazed at what he can fix on your kitchen table. Gene knows his stuff and is trustworthy to let into your home!
L&M Electronics 415-586-1840
2401 Geneva Avenue in Daly City (near the Cow Palace)
They've been around even longer than we have and seem competent/professional.
Full scale/Full service shop.
I've also heard good things about the repair shop at:
Stereo Advisor - Sacramento
http://www.stereoadvisor.com/
Classical Audio Service
Arden Allen
http://www.classical-audio.com/
audioservice@pacbell.net
vintage repair and restoration
World of Sound in Mill Valley, Marin
35 Reed Boulevard
(Behind Strawberry Shopping Center - right off Rt. 101 on the northbound side)
Mill Valley, CA 94941
repair facility that fixes anything - tube, SS, vintage
http://www.worldofsoundmarin.com/
415-383-4343
David Tonelli (Oakland)
510-444-1200
http://www.yelp.com/biz/david-tonelli-oakland
from yelp: David, a radio engineer and record producer, doesn't advertise or market himself. If you have old stereo equipment that needs new life like my McIntosh tube tuner, trust him to do the repairs fairly and reasonably. He is thorough and detailed.