Volume pot does not change volume (Tele)

Hi all!

I've just completed my second Pitbull Tele kit, and on this one I wanted to wire up my own control plate. Both pickups work and sound good, but the volume pot isn't changing the volume until about 80% of the way through the turn, when it drops off quickly to zero. I'm looking for any hints on what I can do to troubleshoot this.

Here are a few more details, with a picture below.

- 500K CTS Audio taper pots (pickups are a humbucker and a P90)
- Orange Drop 0.047ΜF cap
- I have a treble bleed cap and resistor installed (which I purchased from Pitbull - .001uF and 150k-ohm in parallel)
- Standard tele 3-way switch and wiring - no coil splitting on the humbucker
- Behaviour is the same with either pickup
- Behaviour is the same regardless of amp settings, and the volume on my other tele works perfectly with amp
- I've double and triple checked the wiring, as well as test all the ground paths I can think of. Also checked the continuity of all my solder joints
- I haven't added the a tone to volume pot ground wire but they are connected via the plate (tested)

Things I can think might be wrong:

- Pot is bad
- Treble bleed causing an issue - happy to snip it out if anyone thinks it will make a difference
- ???

The tone pot seems to behave in a similar way, but this is also the case on my other tele and I wanted to focus on volume first.

Any advice or suggestions appreciated. In the absence of anything specific my next steps would be (a) snip out the treble bleed, then (b) replace the pot.

Cheers,

David

Attachment 39748

It looks like your .047 capacitor is going through the volume pot lug then grounding on the casing.

Signal from switch should come into volume pot on outer lug. Capacitor should be on same outer lug and go to tone pot. Opposite outer lug on volume pot gets tied to case/ground. Signal leaves volume pot on middle lug and goes to jack.
Here's a diagram with your setup, less the treble bleed:
https://www.prsguitars.com/documents...body2_2017.pdf

I hope this helps.

Also, typically the capacitor goes between volume outer/signal input lug, and the middle lug on the tone pot. Then the outer 'output' of the tone pot goes to ground on the tone pot casing. Then there would be a ground wire from tone pot casing to volume pot casing.

From what I can see, it looks correct (for 50's style wiring) but a birds-eye view would be better to see where everything is going.

FWIW I would re-flow the solder for the cap on the back of the volume pot. It looks like it could be a cold joint.

On another note, what brand is you HB? The wire colour code for the coils and grond has me confused. This would have no effect on the volume control issue, but it caught my eye.

Thanks Joe for the prompt reply. I can't remember exactly where I got it from, but the diagram I used is below (it's upside down so that it aligns with the photo I took). This is also what I've seen on a few YT videos. Clearly it doesn't work though!

Attachment 39749

After reading your post I went to wiring diagrams on my pup website and they are pretty much what you've described:

Standard tele:
http://www.irongear.co.uk/2xtele_sc_..._blade_v08.gif

My pup combo but with a different swtich:
http://www.irongear.co.uk/1_x_humbuc...e_v01_igwm.gif

I'll make the updates, but are you able explain the differences?

Also I assume the treble bleed goes in the same place, i.e on the volume pot between the switch input and jack output?

Quote:

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Originally Posted by McCreed

From what I can see, it looks correct (for 50's style wiring) but a birds-eye view would be better to see where everything is going.

FWIW I would re-flow the solder for the cap on the back of the volume pot. It looks like it could be a cold joint.

On another note, what brand is you HB? The wire colour code for the coils and grond has me confused. This would have no effect on the volume control issue, but it caught my eye.

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Yes, that joint looks dodgy to me too, but I've tested it and it seems OK. Will fix anyway.

The pickup combo is form IronGear - a Rolling Mill and an Alchemist P90 ...
http://www.irongear.co.uk/irongear_pickups_036.htm

Quote:

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The pickup combo is form IronGear

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Ahh, ok. That explains the colour code difference from Seymour Duncans as well as others.

Edit: sorry, I missed your original comment about the tone pot grounding.

Yes, a bird's eye view would help.

The one difference I see between your schematic and the PRS one is that the tone pot 'input' and 'output' are reversed. It seems like that shouldn't matter, but maybe try playing with the tone knob while you change the volume? Just a thought...

Quote:

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Originally Posted by davidxw

I'll make the updates, but are you able explain the differences?

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On closer inspection of the two different tele wiring diagrams there is no difference - it doesn't matter weather the signal goes to the input or wiper terminal as long as the tone cap goes to the other, and is grounded.

I'll take another photo tonight, as well as check/improve the dodgy looking cap ground connection ...

Here is a birds eye view of my control plate, with a (slightly) better job on the cap ground:

Attachment 39750

That's a head-scratcher... It all looks correct to me. The cap/ground joint looks much better too.

My only suggesions are diagnostic not really a fix.

1) I would remove the treble bleed and see if the pot behaviour changes. (maybe the wrong value resistor got put in there and is affecting the taper)

2) completely desolder the volume pot and check the taper with a multimeter. Maybe it is just a junk pot. It does happen, and I've had it happen once (in about 17 years of doing this stuff).
I think CTS Logarithmic pots are around 90/10% split, meaning at the halfway point in rotation, you should read approximately 90% of the total resistance.

Edit: I think I was mistaken again - sorry, trying to learn and help at the same time. It's confusing because there are so many variations of essentially the same thing. I just can't wrap my head around pulling the signal to tone from the volume INPUT rather than the OUTPUT. It seems like the signal can bypass the volume pot.

Here's a schematic from Fralin Pickups. I flipped it upside down to help align with your setup. It's basically what you have but tone pulls from the volume OUTPUT.

Using the same set of pickups for my LP kit atm. Sorry to hear about the issues, i know it wont effect a tele build but the pickups use diff capacitors on mine. .47 for the p90 and .22 for the rolling mill.
Im a wiring novice so prob talking rubbish. Hope you get sorted.


Sent from my iPhone using Tapatalk

Thanks again all for the help - this afternoon after discovering that there was very little change in resistance between the volume input and output terminals as the pot was turned I snipped out the treble bleed bits (as they were the only other things in that part of the circuit) and that's fixed the problem. I probably should try to figure out exactly what's going on with the treble bleed circut but I'll leave that for another time.

Quote:

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Originally Posted by McCreed

1) I would remove the treble bleed and see if the pot behaviour changes. (maybe the wrong value resistor got put in there and is affecting the taper.

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Yes, this did the trick! Also as you suggested my next step was going to desolder everything from the pot and test.

Quote:

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Originally Posted by Joe Garfield

Edit: I think I was mistaken again - sorry, trying to learn and help at the same time. It's confusing because there are so many variations of essentially the same thing. I just can't wrap my head around pulling the signal to tone from the volume INPUT rather than the OUTPUT. It seems like the signal can bypass the volume pot.

Here's a schematic from Fralin Pickups. I flipped it upside down to help align with your setup. It's basically what you have but tone pulls from the volume OUTPUT.

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Yes, I'm a bit confused by this too, however I did find this article which explains some of the differences between 50s, 60s and modern wiring which helped. Also as you've said there are many ways of wiring components into what effectively are the same circuit which doesn't help when you are learning and troubleshooting!

(thanks also for flipping your picture ;)

Quote:

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Originally Posted by chunkosauras

Using the same set of pickups for my LP kit atm. Sorry to hear about the issues, i know it wont effect a tele build but the pickups use diff capacitors on mine. .47 for the p90 and .22 for the rolling mill.
Im a wiring novice so prob talking rubbish. Hope you get sorted.

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Funnny you should mention this - after putting the control plate back in I was cleaning up all the packaging that had accumulated in my parts box and only just noticed that a different tone cap was suggested for each of these pickups. I only have one tone pot so maybe that's something else I can play with another time.

Well that's a good result.
If you haven't chucked the resistor in the bin already, have a look at the bands and see what the value is.

I can never remember just by looking at them, I have to reference a chart nearly every time. Might even be worth clipping it out and measuring it with your multimeter. The whole thiong would make me very curious with a need to know!

FWIW, if you still are going to put in a treble bleed, I find just a single .001uf cap works well (102 code).

Quote:

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Originally Posted by McCreed

Well that's a good result.
If you haven't chucked the resistor in the bin already, have a look at the bands and see what the value is.

I can never remember just by looking at them, I have to reference a chart nearly every time. Might even be worth clipping it out and measuring it with your multimeter. The whole thiong would make me very curious with a need to know!

FWIW, if you still are going to put in a treble bleed, I find just a single .001uf cap works well (102 code).

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Yep, I'll definitely have a closer look, and thanks for the suggestion. Will report back if I find anything interesting!

I've checked the resistor on the treble bleed circuit (measured and colour code), and it's 150 ohms rather than 150K ohms as advertised in the "kit". I'm no expert but I'm pretty sure that was the cause of the problem ...

OK, I'm starting to doubt myself now. Pitbull advertised their "capacitor and resistor fidelity upgrade" as having a 150k ohm resistor, but I'm pretty sure I got a 150 ohm resistor. This is their picture, which I also think is 150 ohms - am I completely misreading the bands/code (I know the colours aren't great but I would have thought the multiplier would have been much higher for 150k (yellow))?

Attachment 39805

What are the band colours from left to right with the gold band on the right?

Using the 4 band system (as shown) 150k ohm should be Brown, Green, Yellow, Gold*. (*depending on tolerance)

4 band 150 ohm = Brown, Green, Brown, Gold. (which is what the picture kind of looks like, but hard to pick if the second band is green)



edit to add:

5 band would be: 150k ohm = Brown, Green, Black, Orange, [Tolerance value varies]

150 ohm = Brown, Green, Black, Black, [Tolerance value varies]

Quote:

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Originally Posted by McCreed

What are the band colours from left to right with the gold band on the right?
4 band 150 ohm = Brown, Green, Brown, Gold. (which is what the picture kind of looks like, but hard to pick if the second band is green)

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Yes, that's what I thought and even though it's hard to pick the second band the third band is definitely not yellow!

If the provided resistor is definitely 150 ohm instead of 150k ohm, I think it's worth raising with Adam at PBG.

Maybe not so much for the $3.95 it cost, but who knows how many others have been sold that may be the incorrect value.

Yes, I did that this afternoon, with a link to this thread ....

Adam has confirmed that the last batch of these kits were indeed made with the wrong resistors, and he'll send me out a replacement when ready.

Quote:

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Originally Posted by davidxw

Adam has confirmed that the last batch of these kits were indeed made with the wrong resistors, and he'll send me out a replacement when ready.

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That's a good result. It's too bad it happened, but at least it's getting rectified.

One has to wonder how many got shipped out before the discovery.