Hum at J Pickup Squier Jaguar Vintage Modified Active

Hi I have a Squier Vintange Modified Jaguar Active Bass and I have a terrible hum at the J pickup. When I turn off the J pickup (single coil) the hum stops. I checked the grounding and everthing seems to be connected, the onky thing I discovered was a poor conductive paint job by the makers and the ground cable from the bridge it is connected with the grounds from pickups to the trebble boost and the cavity ground cables are connected to the p pickup pot. I repainted and waiting for the paint to dry to see if the problem was corrected. Anyway, I would like suggestions in case this doesn't work. I was thinking re do the shielding with cooper tape or replace the J bass pickup. Thanks in advance.

 

Also hum low intensity when treeble boost is off