G&L Legacy not hum-cancelling in position 4

[yunger]

i just bought a used legacy with 3 identical, unmarked, alnico single coil pickups. the guitar is a 1996 model so i am assuming these are house wound pickups.
i am getting hum cancelling when between bridge/middle but not between middle/neck.
common sense tells me to swap the bridge and middle pickup locations. not sure why they would be misplaced to begin with.
is this the thing to do or is there more to it than that?
thanks

[52 Bill]

The first thing to check is the wiring of the neck pickup. Try reversing the leads to reverse the phase and see if it humbucks with the middle pickup.

To test the theory that the other two pickups were switched, take a compass and see what the magnetic polarity of the pole pieces are.

[Mark Hammer]

Good advice to verify the polepiece polarity of the pickups. Since you get hum-cancelling when using M+B, but NOT N+M, however, it is possible that the neck and middle pickups share a polepiece orientation in common with each other, but not in common with the bridge. One possibility is that the middle and bridge pickups were flipped (i.e., middle pickup is sitting in the bridge position). It is also possible that a new pickup was installed, but appears to be original because the cover and other hardware were retained (I know little about G&L pickups so I may be out to lunch and they may easily discernible from other brands).

The possibility that one of the pickups is wired wrong is also legitimate. You wouldn't notice any tonal impact of that when using one pickup at a time. But if you select N+M and the resulting tone is more hollow and nasal sounding than clucky, it is likely they were wired up (or rewired up) improperly.

[big_teee]

All wise info!
On most Strat pickup formats, Usually the bridge and neck are South up wound Clockwise.
Middle is usually wound CCW, North up.
Good Luck,
T

[yunger]

The first thing to check is the wiring of the neck pickup. Try reversing the leads to reverse the phase and see if it humbucks with the middle pickup.

To test the theory that the other two pickups were switched, take a compass and see what the magnetic polarity of the pole pieces are.

the compass says:
neck-south up
middle-south up
bridge-north up

i think i'll swapp the m/b pickups and see if i get lucky before i reverse any leads. they are grounded to the back of the volume pot..blah.

thanks for all the info.

[yunger]

it worked!

i noticed something weird though.
in the bridge and neck pickups (the ones that are now "south up" polarity) the high and low E strings are significantly quieter than the other strings.
this doesn't happen while using the middle pickup.

i wonder if this somehow has anything to do with this polarity configuration?

[yunger]

i did a little more investigative work by touching each pickup pole with a screwdriver. i found that the outer two poles of the neck and bridge pickups appear to have little to no magnetic strength.
can this be fixed?

[Mark Hammer]

So my hunch was right. Vindication!!

Yes, you can recharge polepieces with a string-enough neodymium magnet (a 3/4" diameter one ought to be strong enough. You can also reverse their polarity to, so you probably want to a) keep track of which side of the neodymium is north and south, and b) do your neck and middle pickups in a way that assures the magnet is affecting one but NOT the other.