hi everybody, I got the following problem, see if anyone can help... I have a Fender twin-amp, the '94 edition. The reverb does not work anymore, though if I "shake" the amp you can hear the reverb's coil noise coming out the speaker. So it seems the sound goes from the reverb unit to the amp but not from the amp to the reverb unit... any idea about what the problem could be? thank you!