Tone pots issue

[Paul Buckland]

I recently installed an SD fully loaded pick guard on my Fender Strat. The two tone pots are acting as volume controls such that when either is set at the zero position no amplification of the volume occurs. A solution to this problem would be much appreciated.

 

[Artie]

That usually means they aren't grounded properly. Look carefully over all the ground points.

Or, the caps are shorted or are the wrong value. Such as .47 instead of .047. Check grounds, check that a bare ground wire, (like the one that goes to the trem), isn't touching something when the pickguard is lowered into the cavity.

Also, is the control cavity shielded? Look for indentations to see if the 5-way is pushing down into the shield.

With the pickguard leaning out, tap on the pups and operate the tone controls. If they affect the "tap", then something is touching when you lower it into the control cavity.

 

[Paul Buckland]

Many thanks for your reply Artie 2. I’ll use this info if I have trouble with the next installation.

 

[beaubrummels]

Welcome to the forum!

If tone at zero is quieter volume, the pots aren't grounded.
If tone at zero is no volume, the first cap leg is shorting to ground before passing signal through the other side of the cap.

 

[Paul Buckland]

Thank you BeauBrummels. Both tone pots (caps?) are at zero volume when the tone controls are set to zero. My wiring looked fine (no bare wires to touch anything else) so I’m at a loss to know how both tone pots could be shorting out. A new unit is on the way ….

 

[Bill Dennis]

Thank you BeauBrummels. Both tone pots (caps?) are at zero volume when the tone controls are set to zero. My wiring looked fine (no bare wires to touch anything else) so I’m at a loss to know how both tone pots could be shorting out. A new unit is on the way ….

You are misunderstanding. They are not shorting out. The opposite in fact. They need to be grounded. Can you post a photo?

 

[freefrog]

A tone pot has exactly zero influence on the sound if it's not grounded. So the only possible explanations in this case are wrong cap value (albeit a 470nF cap instead of a regular 47nF would still let a Strat PU resonate at 200hz and shouldn't cut totally the sound) OR, as said by Artie and Beau': shorted tone controls conducting the signal directly to ground instead of routing it through the cap(s)... which would actually change them in secondary volume controls.

PICS of the actual wiring as it is Would help to help...

 

[beaubrummels]

Thank you BeauBrummels. Both tone pots (caps?) are at zero volume when the tone controls are set to zero. My wiring looked fine (no bare wires to touch anything else) so I’m at a loss to know how both tone pots could be shorting out. A new unit is on the way ….

It's not the pots, is the cap, as I stated. In a Strat wiring, both tone pots use the same cap. If the jumper between the tone pots or the first leg of the cap touches ground, it will behave like a volume control because it bypasses the cap and shunts the signal to ground through the pot.