Drawing a complete blank on this one from all the usual manual sites and search engines. Anyone got the schematics for a Roland JC-50? Numbers on the PCB are "AP110" and "141-110"
It dates, I believe, from around 1978, and is not the same as others in the JC (Jazz Chorus) series such as the JC60 or JC120. I particularly need the bit that shows the wiring of the "Vib-Off-Chorus switch. Someone has replaced it, and it doesn't work. I am pretty sure that it has been wired wrongly, but with eight tags and five wires, there's a lot of potential combinations ... The vibrato oscillator is running as you can see it on a 'scope, and the speed and depth controls work. It's just not modulating the signal. As to whether the chorus circuitry is working, is anyone's guess.
TIA
Arfa