Bass wiring, tone acting like master volume

[Vid]

Hello all! New guy on the forum here...

I just completely replaced all the wiring on a buddy's japanese Fender P bass that has a passive split P pickup in the neck and a passive J at the bridge. It has one vol for each pup and a single tone control. I duplicated the wiring that was there (I think... LOL) and now the tone pot acts more like a master vol for the two pickups. Both vol pots work fine and independantly, but the tone pot seems to want to control both pups like a master vol, and it has no effect on tone.

I have searched this forum, and others online looking for a schematic but no luck.

Thanks much for any direction with this matter.

Vid Sutton, Riverside, CA

[Jazz P Bass]

Fender Jazz Bass Special

Is the bass like the one in my icon?
1982, Japanese made.
J pickup
Single Bridge pickup.
3 way toggle. Neck, Both, Bridge.
Independant volume controls & one tone control.
The tone pot is a dual pot with center detent.
Wiring.
Each pickup goes to the 3 way switch .From there each pickup goes to the upper leg of the respective volume pot. The end leg is at ground.
The middle leg (the wiper) goes to the tone control.
The tone pot, being dual, is wired so one end of the pot goes down to the lower pot, but on the other end.
Tone capacitor comes off the middle leg to ground.

My bass is at my sons school.
I will gwt it tomorrow & open the cover to verify.

[FunkyKikuchiyo]

Hard to say without seeing it, but if it is wired correctly it is usually a sign that the capacitor is bad. If the cap isn't providing any capacitance and just going straight to ground (that is, as though you just put a wire in place of the cap), then the whole tone control circuit is effectively a volume control circuit.

If it isn't wired correctly, look at your wiring to make sure that any flow of electrons must go through the capacitor before going to ground. Sometimes leaving the legs on the cap too long can result in a short against the back of a pot or maybe you've just been putting some wires in the wrong places.

Less often, it is a sign that the pickups are open. Sometimes a bad pickup will give sound, though not a great sound. The volume will go away when you roll down tone. If it is happening on both pickups and you otherwise know the pickups to work okay, then I doubt this is the case.

[Vid]

JPB, it has a radiused body similar to an Aerodyne, but it is not an Aerodyne. The finish is a vintage tinted clear (light amber) over a very thin flamed maple laminated top.

Funky, I installed larger sized pots which called for a slight enlargement of the cavity around the tone pot. It is a tight fit and could be something is shorting out the cap, or that the cap is no good.

I'll investigate the bass this week and keep you updated. Meanwhile thanks to both of you for the help!

[FunkyKikuchiyo]

Keep in mind that lugs/wires touching any shielding (including the black paint often used in cavities these days) will send the signal to ground. That is often an issue if you're using larger pots. Checking this is easy - see if it works properly when the control plate isn't screwed in versus having it screwed in.

[axpro]

Bad cap or wiring problem. happens pretty often.

also make sure your pots aren't grounding against the control cavity (if you shielded it)