Hi Hans and Default,
After seeing the pickup wiring on the Mars Music X170T I realized my guitar's alternate switching was not working as it was designed. The coil tap switch on my guitar only influenced the bridge pickup. After seeing the wiring I realized that was incorrect. The 2-way switch on the Mars Music model is not a simple switch as shown by Default. Instead it is a Switchcraft (name is on the switch) "stacked switch". On the Switchcraft website under "Stacked Switches" is a generic diagram that is similar to mine.
I decided the easies way to trouble shoot the switch was to route the switch and cables under the HB pickup ring, raise the bridge and then evaluate the settings with the switch exposed. What I discovered is that the switch got out of allignment and various contacts were not making a firm connection. This explained the lack of functionality and the arcing across the switch. I carefully adjusted the multi conductors on the stacked switch back into allignment. The guitar was reassembled and everything seems to be functioning properly.
I am very happy with the results. I'll explain my results. The Mars Music X170T uses a pair of Fender "Guild" humbuckers. These pickups look like standard Guild from the front. On the back they have the Guild name stamped into the bottom housing. The unusual feature of the Fender/Guild HB is that that have terminals for each of the two bobbins on the humbucker. Thus it is easy to access the bobbins to do a coil tap. An additional feature of the Fender/Guild HB is that both ears of the HB have a 3-hole mounting. Thus these pups can be mounted on a standard Guild 2+1 mounting ring or a standard 1+1 ring. The pickup sound similar to Guild HB but I detect a little change in tone that is a little less bright and they seem to distort/growl a little bit more that a true Guild. (These tone differences are subtle and others may have a different audible experiance.) Overall i like the Fender/Guild HB.
Now in the standard wiring the guitar is a N, N+B, B HB arrangement. Switching in the coil tap you now get N, N+B and B SC arrangement. This configuration is very bright with presence. The Bridge PUP is a little weak but nice and sharp. It blends perfectly in the N+B combination. However the Neck SC tone is outstanding. Has a bit of a Franz tone to it. I like it very much. Full and sharp.
Now I just got to hope the switch doesn't fail.
M