Volume pot tests fine, won't roll sound off to zero.

[lordquilton]

Quite suddenly the volume pot (alpha mini) on my Telecaster (Japanese '52 reissue) stopped rolling all the sound off.
The sound at zero is a little less bright, but it's about as loud as when it's on 8.
I replaced both volume and tone pots with brand new VIP pots. I metered and tested both before installing.
Same problem after installation, volume knob doesn't roll the sound completely off at zero.
Actually, that's not the whole story, the pot seemed to be working perfectly in the guitar after I initially put it in there, I went away and had lunch and it was no longer behaving the correct way when I returned.

I removed that VIP volume pot, tested again. Metering "hot" and middle lug showed the pot working fine.
Metering both outer lugs, I got nothing. Perhaps it got cooked?
So I tested and tried another CTS 250k pot for the volume control, same thing.
On the bench, the pot was fine, in the circuit it behaves in the same faulty fashion as the previous 2 pots.
Where it gets really vexing, I took that CTS 250k pot back out, and metered it again.
The functionality between all the lugs is perfect.

I also replaced the output jack (just because) before taking the CTS pot back out. No change.

In the process of all this work inside the guitar, somehow the VLX 54 pickup switch has become mechanically intermittent; an American style pickup selector is enroute.
I have no idea why replacing the switch would make a difference, but I can't think of anything else to do.
The only other thing I can think of is I broke the neck pickup taking the cover off, and a local tech repaired it by reconnecting the broken wind.
The guitar worked fine for several months after that, though.
I joined a band a couple of months ago, and this Tele has been getting a lot more use, so again I'm looking suspiciously at this VLX 54 switch, but I don't know why.

Any thoughts while I wait for this new pickup selector to arrive?

[mikecg]

Hello lordquilton,

Maybe the ground lug connection on your volume pot is open somewhere - dry joint perhaps? If the pot return path to ground is broken, it will then be in series with the input impedance of your amp, and typically, will be unable to reduce the volume to zero.

[ssstonelover]

I had a full volume issue once. It turned out the ground wire on the volume pot to the back of that pot had a 'cold solder' and had broken off (electrically speaking).
Try reflowing the volume pot connections (concentrating on the grounds).

[JohnH]

Definitely sounds like a ground disconnection to explain those symptoms.

[lordquilton]

Thanks everyone.
I dug out another old pot and I cleaned up all the grounds etc,
and ran a dedicated ground from the back of the tone pot too.

The guitar is sounding cleaner and quieter, and there's some actual taper to the pot.
I use the pot to go from clean to dirty, and that's working well enough,
but the sound still doesn't go completely away at zero.

Perhaps I am just not having good luck with the pots.
As mentioned above, I have new hardware coming anyway.

Pickups from David Plummer (Zhangbucker), and a very tidy looking pre-wired harness and control plate from ebay Australia.
I may do a little exorcism after I remove the factory electronics, just in case.

[lordquilton]

The pre-made control plate has been installed, and the issue of the volume pot not fading to zero has vanished.
I'm looking at the old  VLX 54 pickup switch as the culprit, though why it seemed to be the source of the ground issue is of course beyond me.
Everything "upstream" of the switch (the pickups) is unchanged, and every component "downstream" of that switch was changed out multiple times with the same issue persisting throughout, until the new 
control assembly was installed.

(On a side note, the pre loaded Tele control assembly I purchased from Ebay "does the job", but the 4-way switch is not an Oak Grigsby as promised by the listing, and appears to be a Kaish or similar.
The signal audibly drops out between switch positions. Anyone know where I can find good quality, reliable Tele pickup switches?}

[stevewf]

Oct 18, 2024 19:59:16 GMT -5 lordquilton said:

(On a side note, the pre loaded Tele control assembly I purchased from Ebay "does the job", but the 4-way switch is not an Oak Grigsby as promised by the listing, and appears to be a Kaish or similar.
The signal audibly drops out between switch positions. Anyone know where I can find good quality, reliable Tele pickup switches?}

The 4-way switches that I've seen are all make-before-break (and so are the 3-ways and 5-ways).

So if you've got serial/parallel switching, you'll get a sound cut when switching between serial and parallel. Why? Both poles will briefly, at the in-between position, be connecting three things together. For one of the poles the three things will be: PickupA's cold, PickupB's cold and PickupA's hot, so PickupA will be shorted. For the other pole, the three things are: PickupA's hot, PickupB's cold and PickupB's hot, so PickupB will also be shorted.

I Haven't looked at phase swapping (no time!) but I suspect a similar thing will happen, ie sound cuts due to full ground-out.