Volume pot is stuck at 100% permanently

[spleenharvester]

Hi all,

Odd problem with my blacktop stratocaster - initially the volume knob would turn the volume down but never all the way to zero. Now the volume knob does nothing at all. Wiring diagram is below.

With a complete circuit, I measure about 8kOhms between each of the three volume pot lugs, in any combination. If I lift the leftmost wire from the volume pot, the resistance goes back to normal (500K across the outer lugs, 0 ~ 500K ohms between centre and outer lugs depending on where the volume is turned to). If I measure that lifted leftmost wire to ground, I get that 8kOhm reading again, which doesn't really make any sense to me at all.

The problem happens regardless of where the pickup selector is, or where the tone pots are set to. Any idea what is wrong? I'm struggling to deduce where the problem could be if soldering that wire brings all the lugs down to 8K.

[beaubrummels]

Without seeing it, my guess is the volume pot had an intermittent ground that has now broken completely. Is this stock wiring going bad? Or did you do modifications and this started happening?

[eclecticsynergy]

Likely a bad pot, either faulty to begin with or damaged since.

[GuitarDoc]

If I measure that lifted leftmost wire to ground, I get that 8kOhm reading again, which doesn't really make any sense to me at all.

8k in all switch positions? That reading should change as you change the position of your switch.

Sound like your pots are fine. The problem is with your switch (the switch per se is probably fine, but the wiring is faulty). Check VERY CAREFULLY that you have it wired as in the diagram with no shorts at any contact or to ground. Even one stray wire from a stranded wire could cause a problem.

Several clear pics of your actual wiring showing every connection would be helpful.

[spleenharvester]

After some more testing it weirdly started behaving itself, but I am getting some inconsistent readings off the volume pot so I'm going to replace it. I've had a really good look at the switch wiring and can't seem to find anything wrong. Will update as to whether it fixes the problem/stays fixed.

[spleenharvester]

Replaced today with a genuine Fender/CTS pot, working beautifully now and less noisy (granted fresh soldering might be the reason for this, the original pot was getting a bit silly). Took a look inside the old pot and it's in visibly poor condition, so hopefully the root cause is fixed.

[GuitarDoc]

I still suspect it was the wiring/soldering rather than the actual components.