Hi - I have a circa 2005 Schecter Exotic with Duncan designed pickups. The preamp is an 18V system. Bought used and worked fine for awhile. Now it is shorting out and losing signal. Wondering if anyone knows what the wires are for. Each pickup is hooked up to a green and black, but there are two other wires a white and red that are not hooked up, does anyone know what the red and white are for? Thanks!