The neck pickup on my new SX Jazz fretless was way unbalanced and the bridge pickup was very soft and rolled off. So I removed them to see what was going on: The pickup magnets are two flat bar magnets under the poles. One of the magnets in the neck pickup had unglued, popped off the bottom cover and climbed over the other side causing the imbalance. It looks like non standard construction as it seems in standard jazz bass pickups, the poles are the magnets. The bridge pickup looks intact so I have no idea why it's so much softer than the neck. Suffice to say, the bass is getting a Duncan SJB1 upgrade.