Hi Chris,
I think something about circuit wiring.
1: Locking SW is power SW.
1/4 phone jack is simple, not a switch jack.
It's wiring to LED with registor. The LED will work as power indicator.
2: 1/4 phone jack wiring
The jack is mono type, because the wiring is working as mono.
The wiring to signal point of the jack with one registor.
I think, the miss wiring is here.
Each PU signals need each registors for mono wiring.
I recommend to rewiring with 1/4 SW jack.
I am very interested modified Jazz-B.
If the tailpiece of Chris's bass was modified as this Jazz, it was needed the woodblock to current state.
Eiji
(Message edited by room037 on January 11, 2012)