bandmaster reverb won't adjust

[jc_giggs]

I have a 74 bandmaster reverb. The reverb is not adjustable. When the verb' unit is plugged in and the pedal is in the on position, the reverb is at about 30-50% but I can't turn it up or down. Any suggestions on where to look? I used checked continuity on the reverb pot but Im not sure what kind of figures it was supposed to give. Thanks

[jrfrond]

It could be as simple as a bad ground on the pot. The low side of the pot is soldered to the back of the pot and the ground is established mechanically through the chassis connection. These grounds can and do go bad on occasion. Remove the knob, remove the lock nut and remove the pot. Use a small wire brush to clean the mating surfaces and then replace it and test. If it works, great, otherwise it's a bad pot, which is a 100K linear taper.