New guitar has intermittent wide open volume pot

That is a bit bizarre of a symptom. It could be the ground is a bad connection. That wouldn't make it go full volume, but it would noticeably increase the volume and keep it from being able to turn all the way off. There also could be a stray piece of wire (like the lead going to the tone pot stripped back too far, or something else conductive) jumping across the two hot lugs on the pot. On its own I'm not sure that would do anything, but along with a goofy ground it might make that jump up to full volume more noticeable. If a person knows what to look for in terms of bad connections/cold solder joints/etc a visual inspection might show the culprit.

Replacing the pot very well may not be necessary, but replacing it would let you redo all the connections and it would likely all come out in the wash. I'm having trouble imagining a way that a pot malfunction on its own would cause this problem, except maybe if the lugs were actually losing connection to the internal components, but that is incredibly rare on new pots.

If your buddy likes the guitar, just replace the pot.


If it gets sent back under warranty, they'll most likely just ship out a different guitar.

About the only way a pot (set at any place in the rotation) could go full volume is if it has a treble bypass installed across tabs 2 and 3, and the resistor/cap has failed and goes intermittent dead short.

If that were my guitar and I loved everything else about it (tone, playability, weight, feng shui, etc.), and it had a treble bypass on it, I'd snip it to see if that solved the problem. If it does, replace the TB network components.

If there's no TB, replace the volume pot. It won't be a faulty switch or tone pot.

I got the guitar from him this past Wed, but have been out of town. Hope to look it over tomorrow.

Yay.

He got to play it in church tonight so he was a happy guy.

Understood, that’s how the symptom seemed- the guitar sounded wide open and not controlled by turning it down. It played OK yesterday with no issues but I will keep an ear out see if the problem returns.

I’m pretty sure that your experiment will prove your above statement incorrect
eg with a 250k vol pot and 1M amp input, if the pot loses its common to 0V common, even at min - CCW setting, it can only cut 2dB off the signal level. Which is barely perceptible (it’ll probably seem more like a tone than vol control, as it will cause treble roll off as it’s turned down).
Even going to a 500k vol pot and a 470k amp (or pedal) input impedance, a missing 0V common and min - CCW setting will still only cut about 6dB off the signal. Which is a fair bit, but is still only equivalent to setting most audio taper pots to about 70% (or a linear track pot to 50%).