This is actually not the x-over... It's the high voltage-board (bias) that
transforms the 120V (or 240V) ac-voltage to the thousands of voltage
needed for the stators to work.
These jumpers are most likely to configure the primary side of
the transformer, depending on your location (9-12V, 120V or 240V).
* Are you QuestZ 120V or 240V ?
* What's the label on the transformer ? (Modelno. or serialno.)
I'm VERY interested if you have more of these photos. I alse have ML QuestZ,
but with the 9-12V hv-boards and I'm VERY curious about the differences.
Please email me photos if you have
cheers
// Lars Frisk, Sweden.