ground problem with neck pickup cover ground. Big hum if I touch neck cover when it's in: 1. 1st position -bridge pup on only 2. 4 th position - bridge and neck on (big humbucker type sound) switch engaged with postion 2 & 3 is fine , no hum. Positions 1 thru 4 are all in phase & sound good except for above explanation. The bridge plate is grounded to the back of the volume pot but didn't hum before I connected it, didn't seem to need it but did it anyway. If i try to ground the neck cover to the back of the volume pot or bridge the hum stops but the neck pickup becomes engaged and postions 1 & 4 are the same (bridge and neck on). Pickups are 51 Nocaster bridge and neck.