Just got back from Riteway. Alternator was shot. Teach me to buy a cheap one off eBay last year. Cost for a recon is $195 incl. tax ($75 more if you don't have the core to exchange). Its the same price for an exchange as for a rebuild of your core, except if they rebuild there is no tax. Here's the address,
261 6th Street, San Francisco
415 882 4444
http://www.rite-wayelectric.com/index.html