these days it is next to impossible to find RC-550 for under $500. I got mine off eBay, it was in such poor condition that no self-respecting collector wanted to bid against me. Here is the happy ending for El Diablo: Good efforts prevailed over Evil elements of Time and Indifference
I tried everything I had at my disposal as plastic jets modeller: Windex, alcohol, acetone, lacquer thinners, Naphta, Goof-Off, turpentine, but the only thing which saved me from scraping this licorice goo was lowly generic Paint Thinner. Paint Thinner removed this licorice without any pre-soaking or scrubbing: pure Magic!
Original belts, stretched and hardened. New belts from Turntable Needles are SBR7.2 and FBS10.5
Motor had a dead spot, plus neither motor nor control board give any provision for adjusting play speed. New motor from Pacific Stereo was bought, with CW rotation and 2.5mm shaft mod. Motor is advertised at tapeheads.net: Universal, extremely high-quality replacement cassette capstan motor available NOW!plastic shim was used to reset the pulley at the same height
Getting new JVC antenna was pure luck: one eBay seller responded to my request by selling me like-new RC-550 antenna!
The second part of restoration was more fun because everything already worked.
Red cones are not quite in your face, but the color of blood is there!
Cassette mechanism buttons are color-coded: Rec as Red (as it should be) and Stop/Eject as Light Blue (strange choice for a Stop button!). When fixing the screw post, I colorized some of the epoxy and now all the buttons are happily coloured:
Yet another Mod: when looking at RC-550 Service Manual I noticed that mid-range (SPKR 2) is wired out of phase with woofer and tweeter:
I listened to restored El Diablo “as-is”, the sound was dark and bottom-heavy with some sizzle on top, the way my younger self loved it! Then I disconnected the mid-speaker (working against the huge woofer for mid-range) and El Diablo became a seriously loud boomer! Then I reconnected mid driver in the “standard” configuration. Mid-range came forward, now I can actually hear the lyrics, and tone controls started to control something, not just booming and hiss… In short, when SPKR2 wired “correctly” it is a bbox for the middle-aged guys like me, in its factory configuration it is for the younger folks. To flip two wires, this is the easiest “mod” ever!
Fixing the motor. Original motor had dead spot, but instead of throwing it into the spares bin I took it apart first:
after cleaning and DeoxIT-ing, leaking 10uF cap exchanged. Looks like the rotor has two weights which disconnect power to the motor when pushed away by centrifugal force. Is this some kind of speed regulator?