Vortexion CBL 6

[Diabolical Artificer]

Welcome to the forum. Follow the signal path - have you a sig gen and oscilloscope? If you do insert a low voltage signal in the IP and follow it through, that and check resistors,old carbon types can go high, check any dual gang pots to make sure both pots are the same resistance and also check any connecting wires, a scope is a big help here.

Couldn't find a schematic apart from the one Bill posted (missing circuitry around V1)so can't really point to any possible specific areas.

Andy.