I recently picked up a cheap PJ bass and I'm having some trouble understanding how its wired. When I first bought it I was a bit confused about how the knobs worked -- it seemed like the top (of three) knob was a master volume, and the bottom a master tone, while the middle knob seemed to have no effect. The tech at the shop looked at it for some time in back before telling me that the middle knob was a 'blender knob,' and showed that it was working after all.

I was satisfied with this explanation and other factors (quality of build, low price, having both pickups) and bought it, but I've realized that it doesn't actually have a "blender" knob, but instead has some strange series wiring with two volume knobs where the bridge/jazz pickup seems to be 'slaved' to the neck/precision pickup. Specifically, if I have the neck volume turned all the way up, the bridge volume has no effect on the sound, and if I turn the neck volume all the way down the guitar goes silent completely. I only get full control over the bridge pickup when I have the neck pickup just slightly turned on.

When I looked at the wiring, it seemed to be wired in series, with the ground wire connecting all three pots together, however, in contrast to every diagram I've found online the neck volume pot is wired in reverse (hot pickup wire leads to the 'output' lug rather than the center 'sweeper' lug).

Can anyone explain this? Is it intentional or an incorrect wiring scheme? If I switch it back to how most pickup diagrams show, will the guitar explode in a fiery ball of death? Or should I just scrap the scheme entirely and wire it in parallel?

Thanks in advance for any help!