JVC Victor QL-Y7 turntable

I recently took a chance on this Victor QL-Y7. When it arrived the platter would start to spin but then stop again. The series of switches along the front panel seemed erratic so I squirted them with contact cleaner, whereupon the whole thing stoped working completely. I managed to get one of the switches apart, and the little metal contacts at the bottom were corroded, so I cleaned them up but it made no difference. Sticking a meter across them (removed from the PCB) reveals the resistance when energised ranges from 200 to 400Ω. I figured they were shot, pulled them out and replaced them with new parts, albeit of an entirely different design.

I've replaced most of the electrolytics in the deck now (just waiting for a couple I didn't have). Some of the larger main supply ones were toast.

The platter now turns again as soon as the turntable is powered up, but none of the switches do anything. The two on the motor unit itself, which select 33 or 45rpm, are touch switches which apparently rely on capacitance to work (except they too are unresponsive). I'm assuming the ones on the front panel aren't, as they're plastic, but the fact that the little nipple inside them that bridges the gap between the two metal contacts is made of a rubbery material is making me wonder whether there's something odd about these switches. Does anyone know what the score is with them? I might reinstate them, having now cleaned them all (they're a fiddle to get apart).


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Maybe those switches are conductive rather than capacitive? My Seiko C153 digital calculator watch (from the same era) uses a flexible rubber membrane with a conductive coating to bridge the interlaced contacts. When the coating wears off, the switches stop working. Video here

Good luck! I have a Victor/JVC TT-81 in need of electronic rehabilitation. I may take the easy way out and use a control board from a JL-B37R...
Cheers, Mike