OK, another older L2500 question

[eastcoasteddie]

I wanted to reverse-wire my series wiring to cancel hum (both pups on). My pickups have 3 wires each: black, yellow, white. The black and yellow are wired to the center of the series/parallel switch, each wire has its own connection. Black, yellow, Black, yellow from top to bottom. Black/yellow from the neck pup is on top, black/yellow from the bridge pup is on bottom.
On the right side of the switch are the green caps. One cap for top black/ yellow, one cap for bottom black/yellow). So, I'm guessing this is the Series wiring side of the switch.
On the left side of the switch is the White wiring from the pickups, I'm guessing the Parallel side.

So I figure that to reverse-wire one pickup, I'd swap 2 wires out. Went for the bridge pup. So now I changed the wiring to Black/Yellow (neck), Yellow/Black (bridge).

Turns out this doesn't work. My bridge pup didn't reproduce sound. What's the deal? Which wires should I swap out?

Wired it back the way it was, and it works fine.

[Ken Baker]

If you'd check this diagram of the "old" circuit you'll find that the pickups should have four wires; black, white, yellow, green. Green should be grounded, and this is usually done in the main cavity. In fact, in my admittedly limited experience, I have only ever seen them grounded in the main cavity.

If the green wires aren't brought out to the main cavity, then it may be that the bass has already seen some mods. The green wire is the opposite end of the coil that the yellow wire connects to, so having that green wire available for switching would be important to custom wiring.

Beyond this, I got nothing.

Hopefully, Daveplaysbass will see your post and respond. He is, of course, the person who wrote the definitive single coil mod doc.

Ken...

[eastcoasteddie]

well, the green wire I didn't even mention because yes, it is ground. It doesn't go anywhere near the switch, so relaying information about it is neither here nor there.

Thank's for the diagram!!
Looking at it more closely, I can see that indeed switching the black and yellow wires should work...

[DavePlaysBass]

If you want to switch the order of the coils in series, you should do this on the bridge pickup only:

1) Switch the Yellow pup wire and the White pup wire
2) Switch the Black pup wire and the Green pup wire (that is grounded)

I would only do this in a non shielded bass. If the bass has the conductive paint in it and the pups themselves are grounded in the pup cavity (my Tribby is like this), then DO NOT do what is listed above. Instead just rearrange the capacitor on the bridge side of the series connection as discussed in the other post. In fact the capacitor mod is a lot easier anyway so I would just do that regardless.