Wiring Help

[BigPigPeaches]

Hey folks. I'm working on an old Airline guitar and the wiring has me flummoxed.

 

It's a 2-pickup configuration with separate volume/tone controls for each pickup; output from these then goes to a 3-way 9-pole switch; then to a master volume; then to output. Each pickup has only a hot and lead output, but has three leads going to the switch from the control harness.

 

The 3-way switch is producing neck only (in position 1), bridge only (in position 2), and in position 3 produces the bridge pickup with a thin, nasally sound that sounds curiously like out of phase, but it is only the bridge pickup that's producing sound.

 

My question: What is position 3, if not phase reversed? Just the additional cap?

 

I've attached a wiring diagram. I've eliminated some of the ground traces in order to clean up the diagram. All of the components are correctly grounded in the actual guitar.

 

The notes at top right show which contacts of the switch are active in each position.

 

Thanks as always.

[Mr.Grumpy]

The wiring diagram isn't showing.

[Mr.Grumpy]

As best as I can tell, your assumption is correct. It looks like the 3rd position puts a small capacitor in series with the bridge pickup, and the effect would be as you describe, a "thin" sound with plenty of treble but no bass. Who knows why they did that? Maybe the twangy, plinky sound was "in" for a while. A cheap way to give more tone variations, I suppose.

 

[WRGKMC]

Rickenbackers did the same thing. It was pretty common to do that to get that sharp fender tone. It likely matches the amps sold with the guitar and with different amps it sounded way to trebly. You can just jumper the cap out. I'd leave it there in case someone wants to restore it to stock. You can also use a higher value cap, or just put another cap in parallel and you'll get more bass response.