Tone Pot Lowers Neck Pickup Volume Issue

[cashmoneywill]

Hey all! Running into some new problems with a Fender Highway One Bass I just picked up. The wiring seems to have been replaced at some point (Unless there is actually a grease bucket tone circuit here, but looks like the average wiring job).

The problem I keep running into is that the tone knob functions as it should for the bridge pickup, but it lowers the neck pickup volume for some reason. Tone at 0 essentially mutes the neck pickup, with just maybe 1db of the neck signal coming through.

Any ideas on what is causing this? My thought is that either the cap is bad (which seems odd as the bridge pickup is fine), or that there is some grounding out.

 

[LoveThatBass]

Hard to tell but the tone pot wirelug that the cap connects to is very close to the center wiper (output). Is it shorting?

 

[cashmoneywill]

Hmm. Thought I fixed it, saw some issues with the wiring but still no go. Even changed out the capacitor to an orange drop. Still same issue with only the neck pickup volume dropping when I roll off the tone. Checked the lugs for a short too @LoveThatBass

 

[LoveThatBass]

Try swapping Bridge and Neck signal wires and see if problem moves or stays (as a test )

 

[C Stone]

Probably just the angle but is this a bit of solder or wire bridging the pots lugs?
Really just throwin it out there…

 

[cashmoneywill]

Probably just the angle but is this a bit of solder or wire bridging the pots lugs?
Really just throwin it out there…
View attachment 5204389

Crappy photo! My bad.

There’s some messy soldering, but since then I’ve reconnected the leads on the capacitor and completely replaced it just to test.

 

[LoveThatBass]

Yes that is a messy solder and if bridging the culprit

 

[cashmoneywill]

Yes that is a messy solder and if bridging the culprit

So, to confirm, the solder joint on the capacitor? Or just the wiring in general haha

 

[Wasnex]

Is this the intended circuit?

Not sure, but it looks like the ground from the jack is connected to the terminal of the tone pot rather than the case. Also, I don't see a ground from the tone pot case to the volume control case.

 

[JKos]

it looks like the ground from the jack is connected to the terminal of the tone pot

To me that’s looks like the tip connection. There is no ground wire connected to the jack. The grounding is through the shielding.

 

[cashmoneywill]

Is this the intended circuit?

Not sure, but it looks like the ground from the jack is connected to the terminal of the tone pot rather than the case. Also, I don't see a ground from the tone pot case to the volume control case.
View attachment 5204397

The grounds from case to case were definitely missing, but replaced those and still have the same problem. Super strange

 

[Wasnex]

To me that’s looks like the tip connection. There is no ground wire connected to the jack. The grounding is through the shielding.

Didn't notice the shielding . This would resolve the connection between the pot cases. Also unless the jack is insulated, the ground should travel from the input jack to the shield...no wire is required. Yet there appears to be two wires coming from the jack. Looks like one goes to the wiper and one goes to the leg of the pot the cap is connected to.

AFAIK, The tip should go to the wiper. (IMHO) The extra wire should be removed (edit-->) or connected to the pot case.

 

[SharpCat]

Any shorting from the pot terminals to the plate?

 

[cashmoneywill]

Didn't notice the shielding . This would resolve the connection between the pot cases. Also unless the jack is insulated, the ground should travel from the input jack to the shield...no wire is required. Yet there appears to be two wires coming from the jack. Looks like one goes to the wiper and one goes to the leg of the pot the cap is connected to.

AFAIK, The tip should go to the wiper. (IMHO) The extra wire should be removed (edit-->) or connected to the pot case.

Its so hard to get a good photo (tons of wire crammed into the cavity), but what looks like 2 wires coming off the jack is just a reflection on the metal.

 

[cashmoneywill]

Any shorting from the pot terminals to the plate?

Nothing that I could see, signal doesn’t ground out or anything. The connections are all solid, which is why I am just super lost on how the tone pot is affecting the neck signal volume at all.

 

[JKos]

Disconnect the cap on either end. Does it still do it?

 

[cashmoneywill]

Disconnect the cap on either end. Does it still do it?

Yup. In-between switching out the cap I tried that just in case. So odd.

Bad tone pot maybe? Just confused why it would only influence the neck.

 

[Wasnex]

Nothing that I could see, signal doesn’t ground out or anything. The connections are all solid, which is why I am just super lost on how the tone pot is affecting the neck signal volume at all.

Thanks for the explanation...seems I am not helping ...good luck.

 

[SharpCat]

Totally guessing here...The neck pot is a lot newer than the others (22XX date code)--guessing it was replaced. (You mention it was rewired.) Is it the wrong value? Maybe it's a 100K or 25K or something, so it's more affected by the tone pot drain. Did you try swapping the pickup connections like @LoveThatBass suggested?

 

[Matthijs]

Totally guessing here...The neck pot is a lot newer than the others (22XX date code)--guessing it was replaced. (You mention it was rewired.) Is it the wrong value? Maybe it's a 100K or 25K or something, so it's more affected by the tone pot drain. Did you try swapping the pickup connections like @LoveThatBass suggested?

If that’s the case it would only show when that pot is not on 100%. With the pot on 100% the effect would be equal for both pickups.

this problem has me stumped. As far as I can tell from the pictures and the op’s answers there is a continuous connection between the hot leads from the volume pots to the tone pot and the jack and there is a continuous connection to ground for all pots. If that’s the case I can not think of a way how the tone pot has a different effect on each pickup.