Ive been experimenting changing magnets in my 57/57+ Classic Pu's and suddenly my bridge PU lost volume. When the selector switch is in middle position there is only volume from the neck BUT I can notice a tonal change when turning the bridge tone from 10-1 in this position. There is no volume in the lead or bridge position. Now, after checking all solder joints I sprayed contact cleaner still no bridge volume. Here is the thing, I took the PU cover off and the bridge works fine. When I put the cover back on there was no volume. Any ideas to enlighten me.