Puzzled..?? I've a strange pot.

[retslock]

This is a new one on me. I built a bass that has been working very well until now. This morning I plugged in and as I wound up the volume pot a hum began at bout a 1/4 turn that stayed there until around 3/4 turn then disappeared. Below and above this point all is ok - no hum and clean sound. When I back off a little on the pot it starts up again. There's no loss of volume but touching the plug/bridge/strings cuts out the hum. I haven't opened it up yet to see what's going on because it's only within the above mentioned zone of rotation the pot. I've never come across an earth/ground issue quite like this.
Any suggestions as to why it's only within that dialing zone?

 

[kgbeast]

This looks like a misseired pot.
Usually you connect the output to the wiper of the pot (typically middle terminal). Then the pickup feed and the ground are connected to the side terminals. If you swap the pickup feed and output places, you can get the described condition. So I would check on that.

 

[Jerry Catanescu]

Did you change anything at all in your setup since the last time when you did not have this issue? Cable, amp, any fx?