Roland Jazz Chorus JC 50

[es345]

Hi,

I am searching for the JC 50 schematic later than 1980 ('79 I have). Thanks for help in advance.

Hans- Georg

[Steve L]

1983 Manual

Here is the 1983 (2nd edition) service manual.

Roland JC-50 Jazz Chorus (Ed.2) Service Manual.pdf

Please post your 1979 schematic. I don't think I have that one.

Steve

[es345]

Steve,

thanks for the manual. This is great, it has both schematic and pcb version inside. I have attached the schematic I have, it seems to be a copy of the '79 inside the manual. In the moment I have created a combined picture of the assembly and soldering side, not very professional up to now (see attachment). The background for all that stuff: The volume pot is very scratchy. One possible reason is a capacitor leakage at the previous stage which would result in a DC current through the volume pot. That definitely can create that noise. And for this work it is much faster using an existing document than doing reengineering.

BR Hans- Georg

Edit.

I have rewritten part of the mail. In the beginning I have overlooked that 2 schematics are inside the manual...

[Steve L]

Hans,

Thank you very much for the schematic.

For what it is worth, I have found that most Roland JC amps that have come into my shop have needed to have the potentiometers cleaned in a big way.
You probably have already done it, however if you have not, use a good cleaner/lubricant on all of the pots before looking at the surrounding circuitry or the pot itself.

Steve