out of phase

Can someone explain "out of phase" to me. I have a 69 tele with original bridge pickup. The neck was not original and weak so I had a tech put in a pickup I had laying around. It sounds weak in the middle position. He said it's out of phase
Thanks

A pickup is basically a coil of wire around a magnet. The coil of wire is one single piece of wire and so it has to ends each end is assigned either negative or positive. When the pickups are said to be In Phase this means both of their negative wires are connected and each of their positive wires are connected. Out of Phase is just the opposite, one of the pickups is reversed and it's negative wire is connected with the positive wire of the other pickup and it's positive with the other's negative. What happens I think to the sound of two out of phase pickups is that any indentical signals that each pickup shares will be cancelled out so that only the difference between the two pickups will be heard. This results in very bright honky type of hollow sound. If you don't like the sound of it (understandable) you can pretty easily fix it by rewiring the out-of-phase pickup, with tele's I think most people reverse the neck pickups wire's (make sure you the neck pickup's shield is connected to it's ground wire.). If you need anymore help just let me know.