70's telecaster custom, tone knobs not working

[conorsearl]

I've never seen wires come off the volume pots, go to the center lug on a tone pot and then cross over to the "usually" empty lug before. Would this cause the tone knobs to not work? (which is what's going on right now)

.

 

[beaubrummels]

Yeah, that's bypassing the tone.

 

[freefrog]

I've never seen wires come off the volume pots, go to the center lug on a tone pot and then cross over to the "usually" empty lug before. Would this cause the tone knobs to not work? (which is what's going on right now)

.

Hello,

To me, it makes practically no difference compared to a regular tone pot. A 5Spice sim should show that both work in the same way.

What happens in this case, IMHO/ AFAIK, is this: the grounding is normally materialized by the foil under the pickguard. As the guitar is old, the pots are slightly unscrewed and/or oxidized, or a nut has eroded/ mangled the foil around the axis of the pot. So, the continuity between pot casing and ground is no more there and the tone cap is not connected to ground.

To check it, put a wire between the housing of your faultly tone pot and one obviously grounded part (volume pot housing, braided shielded cable or something like that). If the problem is what I explain, the pot should work again.

This problem often happens on some old Strats or Strat clones, FWIW.

Oh, and I'd inject some Deoxit in these old pots, too, if ever the problem is simply a pot oxidized internally.

 

[Benjy_26]

Hello,

To me, it makes practically no difference compared to a regular tone pot. A 5Spice sim should show that both work in the same way.

What happens in this case, IMHO/ AFAIK, is this: the grounding is normally materialized by the foil under the pickguard. As the guitar is old, the pots are slightly unscrewed and/or oxidized, or a nut has eroded/ mangled the foil around the axis of the pot. So, the continuity between pot casing and ground is no more there and the tone cap is not connected to ground.

To check it, put a wire between the housing of your faultly tone pot and one obviously grounded part (volume pot housing, braided shielded cable or something like that). If the problem is what I explain, the pot should work again.

This problem often happens on some old Strats or Strat clones, FWIW.

Oh, and I'd inject some Deoxit in these old pots, too, if ever the problem is simply a pot oxidized internally.

You ground your pots to the pickguard?

 

[ThreeChordWonder]

The pickguard, if shielded, will (and should) act as a ground, connected to the pot casings through the shaft bushing and shake proof washer.

If is shielded and NOT grounded,, the shielding won't do anything.

 

[Chistopher]

Generally you should not run a wire to your pickguard, as 3CW pointed out it's probably already grounded by the pots. Soldering the pickguard shield is just asking to burn the plastic

 

[ThreeChordWonder]

Generally you should not run a wire to your pickguard, as 3CW pointed out it's probably already grounded by the pots. Soldering the pickguard shield is just asking to burn the plastic

Duh!

 

[conorsearl]

Hello,

To me, it makes practically no difference compared to a regular tone pot. A 5Spice sim should show that both work in the same way.

What happens in this case, IMHO/ AFAIK, is this: the grounding is normally materialized by the foil under the pickguard. As the guitar is old, the pots are slightly unscrewed and/or oxidized, or a nut has eroded/ mangled the foil around the axis of the pot. So, the continuity between pot casing and ground is no more there and the tone cap is not connected to ground.

To check it, put a wire between the housing of your faultly tone pot and one obviously grounded part (volume pot housing, braided shielded cable or something like that). If the problem is what I explain, the pot should work again.

This problem often happens on some old Strats or Strat clones, FWIW.

Oh, and I'd inject some Deoxit in these old pots, too, if ever the problem is simply a pot oxidized internally.

Wow, I'd never experienced that before. I loosened the tone pots, the star washers were lodged in the shielding tape and plastic pretty firmly. Pried those out and re-installed and everything works properly.

 

[freefrog]

Wow, I'd never experienced that before. I loosened the tone pots, the star washers were lodged in the shielding tape and plastic pretty firmly. Pried those out and re-installed and everything works properly.

Glad it works for you now. Enjoy!

 

[freefrog]

You ground your pots to the pickguard?

Me? No.

But it's pretty current to find a shielding foil whose conductive surface connects the pots to ground, no?

My first reply was an hasty attempt to be helpful and not to be exact. Sorry if I've not used the proper words: English is still not my daily language, so I struggle sometimes to be clear...

 

[Benjy_26]

Me? No.

But it's pretty current to find a shielding foil whose conductive surface connects the pots to ground, no?

My first reply was an hasty attempt to be helpful and not to be exact. Sorry if I've not used the proper words: English is still not my daily language, so I struggle sometimes to be clear...

I've never seen foil on a pickguard being used to connect pots to ground, tbh.

 

[conorsearl]

I've seen (and done it too) the cavities with shielding, and little ears that poke over the edge to make contact with shielding tape on the section of pickguard that covers that cavity. Then run a ground wire to the shielding tape in the cavity. I've never had a problem.

 

[beaubrummels]

I've seen (and done it too) the cavities with shielding, and little ears that poke over the edge to make contact with shielding tape on the section of pickguard that covers that cavity. Then run a ground wire to the shielding tape in the cavity. I've never had a problem.

Faraday cage. Very helpful on Fender guitars.

 

[freefrog]

I've never seen foil on a pickguard being used to connect pots to ground, tbh.

As this kind of connections has been abundantly used by Fender, I've seen it many times these last 40 years. YMMV.

Below is the original wiring of two 1954 Strats : there's no ground bus between pots (the wire between the left tone pot and the center tone pot being simply a leg of the common tone cap in each case; tone controls are ground-connected to the grounded volume pot through the shielding foil in both guitars) .

http://www.pinrepair.com/vgi/fender/...at-july_10.jpg

http://www.pinrepair.com/vgi/fender/54_strat-oct_7.jpg