JazzMaster Single Coil Neck Pickup Weirdness -SOLVED!

[Barry]

This one has me stumped.

I was playing my Squier Affinity Jazzmaster SS tonight, which I bought new in 2022, and everything was normal.
Until it wasn't.

I flipped the selector to the neck pup and...nothing. Nada. Rien. Bugger all.

I immediately thought that the switch might have shorted out since the past couple of weeks have been very humid here by the Lake.

So I yanked it like a monkey in a Mango tree!
Positions 1 and 2 worked as expected but still nothing from the neck! darn!

I then tapped the poles with a small screwdriver and surprise! The pops came through the amp loud and clear. Huh?!

But when I hit the strings...zilch.
Well, almost. I turned the guitar volume up full and strummed again.

Aha! A signal, but extremely weak. Switching to the bridge gave the loud output as expected.

These strings are fairly new and haven't been played more than a month total so I'm not keen on cutting them to get at the pickup, although it looks like it might be necessary.

I haven't spent a lot of time on this yet, it just happened while i was having a little play before supper, but I am speculating as to what is going on.

It could be a bad solder joint but then how am i getting any signal at all? But then I also suspect it may have something to do with the fact that the poles are magnets not slugs, so they would be capable of generating a signal pop...but that means the wiring is OK? Bad capacitor maybe?

Does anyone have experience with this condition?
Not your typical pup problem and bloody annoying for a new guitar. Very strange.

Click on thumbnail for full view:

[Crusty]

Sound in bridge and bridge+neck means the issue is as you deduced the neck pickup. I doubt a bad capacitor as if I'm not mistaken the only cap on that guitar would be on the tone pot.

Have you checked the resistance on the neck pickup in comparison to the bridge? They should be pretty close, somewhere in the 6K to 9K range (for most P90s anyway). If you get a much higher resistance it could be something as simple as only one strand of braided wire is making a connection. A direct short in the windings could do this also.

Compared to the strings tapping the poles with a screwdriver creates a much more transient spike in signal than strings do.

[Barry]

Thanks for the reply Neal but the problem turns out to be a simple one.
It was in fact the selector switch all along!

I picked up the guitar tonight and...the pup played just fine! But as I worked all the controls the switch would cut out on the neck pup again. Then it would come back again as if nothing happened!

No static, no crackle, just silence, even if wiggled. After a few on and off cycles I finally shot some contact cleaner into it (from the toggle side) and so far it seems to have settled down. I will eventually get at it on the next string change when I can remove the pick guard.

It's amazing how simple stuff can screw you up, even when you should know better!

[Crusty]

3-way switches. One tiny speck of dust.

It sounded like there was way too much resistance somewhere in the circuit. At least it's not a shorted winding or other "knot in the gut" issue.

[Kmaxpe1500]

This happens to my Strat. The pickup switch is below the bridge which gets a lot of dust from my hand while playing. I spray compressed air into it to fix it.

[Barry]

3-way switches. One tiny speck of dust.
It sounded like there was way too much resistance somewhere in the circuit. At least it's not a shorted winding or other "knot in the gut" issue.

Yeah, something weird like that, but I won't know until I can physically get a look at it. It could be something mechanical. Like I said, there was nothing like the usual crackling fuzzy response that you get from corrosion which is why I went down that rabbit hole.

I was immediately concerned that there was an issue with the pickup. But then the darn thing would work again! What sidetracked me was that I got a loud response from tapping the poles yet nothing from the strings. Regardless, you don't expect problems from a barely 2 year old lightly played guitar.

Otherwise, it's really a nice guitar and well made.

[Barry]

...Have you checked the resistance on the neck pickup in comparison to the bridge? They should be pretty close, somewhere in the 6K to 9K range (for most P90s anyway)...

These are not P90's They're Duncan Designed JazzMaster pickups, completely different construction, and this design is a bit hotter than the original JM pups.
The resistance readings are: Neck = 6.63 KΩ, Bridge = 11.18 KΩ, Both = 4.23 KΩ

[Crusty]

Ah! I've used a set of Duncan P90s myself. Pure beast.