Tone pot acting like volume on bridge JB in Modern Player Tele HSS

[alex_rockthenight]

Hey everyone

I'm having an issue with the tone control and possibly the wiring with my Modern Player Telecaster Plus with the bridge humbucker (Seymour Duncan JB). I had the JB installed with the coil split by a guitar tech a while ago. From my understanding (which is very limited on guitar wiring), the wiring for the bridge humbucker seems to be correct. I followed the instructions from the link below for a full series humbucker/north coil tap with a DPDT switch. I included some pictures/videos as well as an explanation below. For context, I have a Hot for Tele STR-2 in the neck, the stock middle pickup and a JB in the bridge.

https://guitarelectronics.com/humbucker-north-coil-tap/

DPDT Switch
Red & White wires are soldered together and to the middle right pole.
Green & Bare wires are soldered together to the bottom right pole + 'a red wire from the same bottom right pole to the back of the tone pot (ground).

Black wire is wired directly to the 5 way switch (it was soldered to a grey wire and taped together to extend it to the switch).

When I turn the tone knob all the way off on the humbucker, it works almost like a volume knob on the clean channel. With some gain, turning the tone knob to zero completely removes any low frequencies. The tone knob works just fine in all of the 4 other positions (Bridge/Middle, Middle, Middle/Neck, Neck).

From the research I've done on this forum, it seems like it could be a ground issue, right? I nor any of the guitar techs (at least that I know of) have touched any other wiring of my guitar except replacing the neck pickup, the 5 way switch and changing the tone cap (I believe it was changed to a .047 if that makes sense?).

What should I look for to correct this issue? I don't think it's the tone pot or capacitor as the tone pot works perfectly in all other positions. I sprayed Deoxit contact cleaner on the switch hoping it would make a difference, but it didn't. I had the Green and Bare wires from the JB wired directly to the back of the tone knob before soldering it with the red wire on the switch, which also made no difference.

https://www.youtube.com/watch?v=3dzfTPnEpFQ&feature=youtu.be

Let me know if any other photos could help. Thanks!

[Bill Dennis]

Oh boy..... That is a hot mess.... Tone pot is a volume pot is usually grounding issue or a bad pot...

The split switch should work as described but is not how I would do it.
The ground "blob" in the middle of the volume pot looks sketchy.

I would consider a clean up and rewire.That's what I would do.

[GuitarDoc]

Almost always when a tone pot acts like a volume pot it is a ground issue. Looks like at least one cold solder joint. I would do what Bill suggested and redo the wiring from scratch

[freefrog]

Hey everyone

I'm having an issue with the tone control and possibly the wiring with my Modern Player Telecaster Plus with the bridge humbucker (Seymour Duncan JB). I had the JB installed with the coil split by a guitar tech a while ago. From my understanding (which is very limited on guitar wiring), the wiring for the bridge humbucker seems to be correct. I followed the instructions from the link below for a full series humbucker/north coil tap with a DPDT switch. I included some pictures/videos as well as an explanation below. For context, I have a Hot for Tele STR-2 in the neck, the stock middle pickup and a JB in the bridge.

https://guitarelectronics.com/humbucker-north-coil-tap/

DPDT Switch
Red & White wires are soldered together and to the middle right pole.
Green & Bare wires are soldered together to the bottom right pole + 'a red wire from the same bottom right pole to the back of the tone pot (ground).

Black wire is wired directly to the 5 way switch (it was soldered to a grey wire and taped together to extend it to the switch).

When I turn the tone knob all the way off on the humbucker, it works almost like a volume knob on the clean channel. With some gain, turning the tone knob to zero completely removes any low frequencies. The tone knob works just fine in all of the 4 other positions (Bridge/Middle, Middle, Middle/Neck, Neck).

From the research I've done on this forum, it seems like it could be a ground issue, right? I nor any of the guitar techs (at least that I know of) have touched any other wiring of my guitar except replacing the neck pickup, the 5 way switch and changing the tone cap (I believe it was changed to a .047 if that makes sense?).

What should I look for to correct this issue? I don't think it's the tone pot or capacitor as the tone pot works perfectly in all other positions. I sprayed Deoxit contact cleaner on the switch hoping it would make a difference, but it didn't. I had the Green and Bare wires from the JB wired directly to the back of the tone knob before soldering it with the red wire on the switch, which also made no difference.

https://www.youtube.com/watch?v=3dzfTPnEpFQ&feature=youtu.be

Let me know if any other photos could help. Thanks!

Simple question: do you get a normal DCR reading when the bridge pickup is selected alone?

[alex_rockthenight]

Thanks Bill and GuitarDoc for replying. I guess I didn't realize how messy that blob of solder looked like on the volume pot. I did try to unsolder and resolder (after stripping new wire) all of the grounds on the volume pot. I thought for sure it would do something, but it made no difference. I may end up taking this to a guitar tech because I think cleaning up/rewiring from scratch is out of my skill level. I'm only going to make it worse.

Freefrog, I'm guess DCR reading has to do with the resistance, right? I don't have a multimeter, but I'm going to get one and get back to you. Do you think it could be a faulty bridge pickup?

[beaubrummels]

This might be a long shot, but, even though you have insulation correctly on the legs of the tone cap, it looks like the leg right by the cap itself might be contacting the back of the pot and shorting out the cap - which would effectively make the tone a volume. Try bending the cap away from the back of the pot and see if anything changes.

[freefrog]

Freefrog, I'm guess DCR reading has to do with the resistance, right? I don't have a multimeter, but I'm going to get one and get back to you. Do you think it could be a faulty bridge pickup?

If your tone pot was acting like a volume in all positions, I'd say what our fellow members said.

As your tone pot behaves like that with the bridge PU only and as I've heard your YT sample, I effectively think that your bridge PU has to be tested.

So, find a cheap multimeter, set it to read kiloOhms and put its probes on the ground and hot of your bridge pickup: it should read around 16.5k (16 500 Ohm) or a bit less if the pots are in the circuit (+/- 15.5k if the pots are 500k, 14.5k if they're 250k and so on).

Compare to the other pickups tested in the same way.

If the bridge PU gives a normal DCR reading, test again its DCR from the output jack of the guitar.

I'll share further explanations if any (or both) of these measurements show(s) a problem.

EDIT - Yep, DCR stands for "direct current resistance", BTW. :-)

[ArtieToo]

A tone pot acting like a vol pot is often due to wrong cap value too. Like accidentally using 0.47 uf rather than 0.047 uf. It depends on if it was working properly, then stopped. Or has been that way from the beginning.

[hamerfan]

I guess Beau or Artie is right.

[GuitarDoc]

This might be a long shot, but, even though you have insulation correctly on the legs of the tone cap, it looks like the leg right by the cap itself might be contacting the back of the pot and shorting out the cap - which would effectively make the tone a volume. Try bending the cap away from the back of the pot and see if anything changes.

I noticed that cap wire too. When the control plate is put back onto the guitar body, it would be reasonable to assume that the cap would get pushed down and that wire make contact with the back of the pot. That would definitely cause it to act like a vol pot.

Put some electrical tape on the back of the pot so that cap wire can't make contact and I bet it'll be good to go.

[alex_rockthenight]

I got a multimeter and I tested the bridge JB with the guitar cable method and I didn't get a reading at all. At first I thought I was doing something wrong, but when I switched to the other pickup positions, I got a reading in all of them. I have a SD Hot Tele in the neck and it read around 9.88K which is pretty much the DCR it should be. It seems that the problem really is the pickup. It's a shame cause I quite enjoyed the JB when it worked properly. I really appreciate all the help from everyone and honestly didn't expect so many replies. Thanks everyone. I've learned to make sure to have the right tools and knowledge before messing around with stuff in the future! Now it's time to replace that pickup!

[freefrog]

Sorry for you. :-/

I expected your answer after having heard your YT sample.

What you've got is most likely a "capacitive pickup": the wire is broken in one of its coils BUT this wire stays aligned with itself and forms an accidental capacitor. Hence the impossibility to read any resistance.

It happens and it's not that rare. Outside of the cases that I've repaired myself, such pickups have apparently been found in famous guitars:

https://www.tdpri.com/threads/don-ma...up-mod.289815/

http://forum.metropoulos.net/viewtopic.php?t=39638 ).

In such cases, a tone control behaves as if it was wired just after a series capacitor.

For anyone who would appreciate the related sound, with tighter bass: just wire a normal JB in series with a 4,7nF cap... but put this cap "after" the tone pot and this pot will react normally.

Before to change the JB (or after having changed it, if you want to resell it), you might try to inspect its coils with a jewel magnifier: in many cases, the wire is broken on an external layer and in some situations, it can be repaired with a bit of care.

As a footnote, I post a pic showing how a tone pot reshapes the response of a pickup normally (in blue), and how it alters the volume when there's a capacitor in series with the pickup (which is the same thing than when the pickup has a broken capacitive wire; see the orange line).

These precisions being shared for anyone who would have the same issue and would want to check / understand what happens...

[freefrog]

Side note: I've tried to edit my former answer for questions of typo and got multiple error messages, FYI. Apparently, the added pic causes a bug although I use an updated Windows 10.

[alex_rockthenight]

Thanks for the help and explanation freefrog! I think I'll just put the JB away for now as it had a good run. I never would have expected the pickup to be the problem as for a while I thought that sound was just the EQ of a JB. I can see how it has its place but I'm no EVH

[Mincer]

Side note: I've tried to edit my former answer for questions of typo and got multiple error messages, FYI. Apparently, the added pic causes a bug although I use an updated Windows 10.

Can anyone edit their posts and get the same error? I am not getting it on mine. I am using the default VB5 style. What are you using?