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Guitar Discussions -> LP volume pot problem?
There are 8 messages in this thread.
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LP volume pot problem? - Lee Roberts - 13:25 13-11-08
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Hello all,
The guitar player in my band (I'm the bass player and de facto guitar
tech) is having trouble with his early-90s Les Paul Standard. This
problem started a few months ago, went away on its own for a while,
and now it's back. Here's the deal:
- Neck pickup soloed: no output
- Bridge pickup soloed: works fine
- middle switch position: no output at all with both volume pots wide
open. Here's the weird part -- when I back off on the neck pickup
volume a little (down to 8 or so), voila I've got sound. It then cuts
out again when I roll the volume all the way down to 0, but it's my
understanding that Gibsons are supposed to do that.
Does this sound like a wiring/ground problem, a bad pot, or both? My
only (very limited) guitar electronics experience has been with Strats
and I've never seen anything like this. Thanks for any advice!
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Re: LP volume pot problem? - Meat Plow - 13:43 13-11-08
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On Thu, 13 Nov 2008 11:25:14 -0700, Lee Roberts
<lroberts89@netscape.net>wrote:
>Hello all,
>
>The guitar player in my band (I'm the bass player and de facto guitar
>tech) is having trouble with his early-90s Les Paul Standard. This
>problem started a few months ago, went away on its own for a while,
>and now it's back. Here's the deal:
>
>- Neck pickup soloed: no output
>- Bridge pickup soloed: works fine
>- middle switch position: no output at all with both volume pots wide
>open. Here's the weird part -- when I back off on the neck pickup
>volume a little (down to 8 or so), voila I've got sound. It then cuts
>out again when I roll the volume all the way down to 0, but it's my
>understanding that Gibsons are supposed to do that.
>
>Does this sound like a wiring/ground problem, a bad pot, or both? My
>only (very limited) guitar electronics experience has been with Strats
>and I've never seen anything like this. Thanks for any advice!
Get an ohm meter.
http://www.guitarnuts.com/wiring/stockgibson.php
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Re: LP volume pot problem? - Jim - 13:46 13-11-08
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Lee Roberts wrote:
> Hello all,
>
> The guitar player in my band (I'm the bass player and de facto guitar
> tech) is having trouble with his early-90s Les Paul Standard. This
> problem started a few months ago, went away on its own for a while,
> and now it's back. Here's the deal:
>
> - Neck pickup soloed: no output
> - Bridge pickup soloed: works fine
> - middle switch position: no output at all with both volume pots wide
> open. Here's the weird part -- when I back off on the neck pickup
> volume a little (down to 8 or so), voila I've got sound. It then cuts
> out again when I roll the volume all the way down to 0, but it's my
> understanding that Gibsons are supposed to do that.
>
> Does this sound like a wiring/ground problem, a bad pot, or both? My
> only (very limited) guitar electronics experience has been with Strats
> and I've never seen anything like this. Thanks for any advice!
It sounds to me like the neck volume pot has a short when it's supposed
to be at max volume.
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Re: LP volume pot problem? - Jim - 13:48 13-11-08
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Lee Roberts wrote:
> Hello all,
>
> The guitar player in my band (I'm the bass player and de facto guitar
> tech) is having trouble with his early-90s Les Paul Standard. This
> problem started a few months ago, went away on its own for a while,
> and now it's back. Here's the deal:
>
> - Neck pickup soloed: no output
> - Bridge pickup soloed: works fine
> - middle switch position: no output at all with both volume pots wide
> open. Here's the weird part -- when I back off on the neck pickup
> volume a little (down to 8 or so), voila I've got sound. It then cuts
> out again when I roll the volume all the way down to 0, but it's my
> understanding that Gibsons are supposed to do that.
>
> Does this sound like a wiring/ground problem, a bad pot, or both? My
> only (very limited) guitar electronics experience has been with Strats
> and I've never seen anything like this. Thanks for any advice!
BTW, if he wants the setup that allows separate volume control when the
middle switch position is selected, when you replace that volume pot:
Reverse the two wires on both volume pots that do NOT go to ground.
Leave the ground connection alone, reverse the other two.
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Re: LP volume pot problem? - Bob - 14:28 13-11-08
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Jim,
Will this wiring work on an Epiphone Les Paul as well?
Thanks
"Jim" <jim@askmebeforeyousend.com> wrote in message
news:hpOdncnBt8UR64HUnZ2dnUVZ_jydnZ2d@posted.isomediainc...
> Lee Roberts wrote:
>> Hello all,
>>
>> The guitar player in my band (I'm the bass player and de facto guitar
>> tech) is having trouble with his early-90s Les Paul Standard. This
>> problem started a few months ago, went away on its own for a while,
>> and now it's back. Here's the deal:
>>
>> - Neck pickup soloed: no output
>> - Bridge pickup soloed: works fine
>> - middle switch position: no output at all with both volume pots wide
>> open. Here's the weird part -- when I back off on the neck pickup
>> volume a little (down to 8 or so), voila I've got sound. It then cuts
>> out again when I roll the volume all the way down to 0, but it's my
>> understanding that Gibsons are supposed to do that.
>>
>> Does this sound like a wiring/ground problem, a bad pot, or both? My
>> only (very limited) guitar electronics experience has been with Strats
>> and I've never seen anything like this. Thanks for any advice!
>
> BTW, if he wants the setup that allows separate volume control when the
> middle switch position is selected, when you replace that volume pot:
> Reverse the two wires on both volume pots that do NOT go to ground. Leave
> the ground connection alone, reverse the other two.
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Re: LP volume pot problem? - Lee Roberts - 15:24 13-11-08
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Jim <jim@askmebeforeyousend.com> wrote:
>Lee Roberts wrote:
>> Hello all,
>>
>> The guitar player in my band (I'm the bass player and de facto guitar
>> tech) is having trouble with his early-90s Les Paul Standard. This
>> problem started a few months ago, went away on its own for a while,
>> and now it's back. Here's the deal:
>>
>> - Neck pickup soloed: no output
>> - Bridge pickup soloed: works fine
>> - middle switch position: no output at all with both volume pots wide
>> open. Here's the weird part -- when I back off on the neck pickup
>> volume a little (down to 8 or so), voila I've got sound. It then cuts
>> out again when I roll the volume all the way down to 0, but it's my
>> understanding that Gibsons are supposed to do that.
>>
>> Does this sound like a wiring/ground problem, a bad pot, or both? My
>> only (very limited) guitar electronics experience has been with Strats
>> and I've never seen anything like this. Thanks for any advice!
>
>It sounds to me like the neck volume pot has a short when it's supposed
>to be at max volume.
Thanks for the response! But I feel like I'm missing something. Why
would the neck pickup by itself not work at all at any volume?
Once I discovered that the middle position started working when I
backed off the neck PU volume, I switched to the neck pickup soloed
and -- nada. The only way I can get any output is the bridge pickup
soloed, or the middle position with the neck volume pot somewhere
between 2-8. The neck pickup by itself has no output at all through
the entire range of the pot.
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Re: LP volume pot problem? - Jim - 15:39 13-11-08
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Bob wrote:
> Jim,
>
> Will this wiring work on an Epiphone Les Paul as well?
Yes, I've done it on mine. While you are at it: If you are the type
that likes to use the volume control to clean up the crunch or
distortion, and you find that it tends to get muddy as you dial it down:
Wire a .001 microfarad capacitor between the wiper and the signal (the
two connections that do NOT go to ground).
And...
If you like to use your tone control, but find that it gets WAY too
muddy as you dial it down: Replace the tone cap with a .01 microfarad.
In both cases, it pays to upgrade from ceramic disc. Lower voltage caps
are fine. I've been using "orange dip" 630V from this supplier. Good
source, fair price, fast shipping: http://www.justradios.com/orderform.html
And, finally... While you are in there, take some compressed air and
blow out the cavities (do NOT direct it towards the pickup windings, and
if using the canned type, keep upright and away from the finish and
front of the pickguard -- bad for plastic!). I once had an Epiphone
that I thought that the pickup switch went bad on. NOT. It was because
there was fine sawdust left from drilling the cavity.
>
> Thanks
>
>
> "Jim" <jim@askmebeforeyousend.com> wrote in message
> news:hpOdncnBt8UR64HUnZ2dnUVZ_jydnZ2d@posted.isomediainc...
>> Lee Roberts wrote:
>>> Hello all,
>>>
>>> The guitar player in my band (I'm the bass player and de facto guitar
>>> tech) is having trouble with his early-90s Les Paul Standard. This
>>> problem started a few months ago, went away on its own for a while,
>>> and now it's back. Here's the deal:
>>>
>>> - Neck pickup soloed: no output
>>> - Bridge pickup soloed: works fine
>>> - middle switch position: no output at all with both volume pots wide
>>> open. Here's the weird part -- when I back off on the neck pickup
>>> volume a little (down to 8 or so), voila I've got sound. It then cuts
>>> out again when I roll the volume all the way down to 0, but it's my
>>> understanding that Gibsons are supposed to do that.
>>>
>>> Does this sound like a wiring/ground problem, a bad pot, or both? My
>>> only (very limited) guitar electronics experience has been with Strats
>>> and I've never seen anything like this. Thanks for any advice!
>> BTW, if he wants the setup that allows separate volume control when the
>> middle switch position is selected, when you replace that volume pot:
>> Reverse the two wires on both volume pots that do NOT go to ground. Leave
>> the ground connection alone, reverse the other two.
>
>
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Re: LP volume pot problem? - Jim - 13:01 14-11-08
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Lee Roberts wrote:
> Jim <jim@askmebeforeyousend.com> wrote:
>
>> Lee Roberts wrote:
>>> Hello all,
>>>
>>> The guitar player in my band (I'm the bass player and de facto guitar
>>> tech) is having trouble with his early-90s Les Paul Standard. This
>>> problem started a few months ago, went away on its own for a while,
>>> and now it's back. Here's the deal:
>>>
>>> - Neck pickup soloed: no output
>>> - Bridge pickup soloed: works fine
>>> - middle switch position: no output at all with both volume pots wide
>>> open. Here's the weird part -- when I back off on the neck pickup
>>> volume a little (down to 8 or so), voila I've got sound. It then cuts
>>> out again when I roll the volume all the way down to 0, but it's my
>>> understanding that Gibsons are supposed to do that.
>>>
>>> Does this sound like a wiring/ground problem, a bad pot, or both? My
>>> only (very limited) guitar electronics experience has been with Strats
>>> and I've never seen anything like this. Thanks for any advice!
>> It sounds to me like the neck volume pot has a short when it's supposed
>> to be at max volume.
>
> Thanks for the response! But I feel like I'm missing something. Why
> would the neck pickup by itself not work at all at any volume?
You said that when you back off of the neck volume, it works normally.
Or not?
>
> Once I discovered that the middle position started working when I
> backed off the neck PU volume, I switched to the neck pickup soloed
> and -- nada. The only way I can get any output is the bridge pickup
> soloed, or the middle position with the neck volume pot somewhere
> between 2-8. The neck pickup by itself has no output at all through
> the entire range of the pot.
Was this guitar previously set up so that when in center switch
position, reducing either pickup to zero also turned down the other pickup?
That's this diagram:
http://static.zoovy.com/img/guitarelectronics/-/wdu_hh3t22_01
There are more than one thing that can go wrong, and lots of things to
check. If any pot was loose in the guitar, the wires could've twisted
around until something touched, or a wire broke. Check the switch for
shorts or breaks.
What happens when you plug in a cable and measure ohms at the end of the
guitar cable in bridge position?
Open it up. Measure all grounds.
Check the pickup. Take it out of the circuit, measure with an ohm
meter. You should get a few thousand ohms.
Next, check all wiring, looking for things touching that should not be
(shorts to ground).
Look for broken wires.
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