The galvanometer receives the positive charge from the battery through a jumper to the chassis (+). The voltage regulator can be placed between the galvanometer and the chassis by removing the jumper.
The ground connection for the voltage regulator can go to the on-off switch where the red wired connect.
Brown wire: from voltage regulator
ground to on-off switch, (-) from battery.
Light Blue wire: from the voltage regulator
output to the galvanometer.
Red wire: from the voltage regulator
input to the chassis (+).
There is just enough room under the hot shoe connector, right over the viewfinder, for the voltage regulator device.