Audio Doctor in College Area runs a pro-audio repair bench at 6555 El Cajon Blvd, San Diego 92115, between Rolando Blvd and Aragon Dr on the eastern reach of the El Cajon Blvd commercial corridor. Founded in 2018 by Mike Rubenhold, a recording engineer and electronic technician who began repairing audio equipment in 2000 and trained under Mike Krewitzky at a predecessor pro-audio shop on El Cajon Blvd, the bench services amplifiers, mixers, powered speakers, synthesizers, and keyboard workstations. Rubenhold holds Yamaha-certified keyboard repair credentials, one of three technicians carrying that authorization in San Diego — a specialization that draws Roland Jupiter-X and Yamaha Montage owners from across the county to the same El Cajon Blvd strip where JC Power Audio Shop handles car-audio installations. The repair queue covers vintage and modern gear equally, accepting boomboxes from the 1980s alongside current-production studio monitors and PA heads. Rubenhold's three decades behind a drum kit and in recording studios shaped the diagnostic approach: every amplifier and speaker cabinet gets a bench test under signal before leaving the shop. The 92115 location sits roughly two miles east of SDSU, drawing a client base of campus music-production students, touring musicians passing through San Diego, and home-studio owners upgrading rack-mount gear. Modification and restoration services extend the bench beyond standard repair into circuit upgrades, capacitor replacements, and re-tubing for tube amplifiers — the same analog signal-chain work that complements the vintage audio and video hardware sold at Kim Hong Video Audio nearby on El Cajon Blvd. Walk-in intake runs Tuesday through Saturday starting at 2 PM, with a current backlog averaging 12 weeks for non-emergency jobs.