The treble switch is failed, y move it and the bass is muted, i have to change all the electronics? cleaning? please help.
A switch is one of the easiest and least-expensive fixes you can have with your bass. It may be as simple as a bad contact, which requires nothing more than bending the offending piece of metal back into place. Even if you have to replace the switch, it probably won't cost more than US$30.00.