Push-pull pot wiring

Johnny333

ICBM said:

Before we go any further... I am going to stop helping if you refer to pickups as "pups" again. I'm sorry, it just infuriates me for no known reason, but so much that I can barely read a post with it in.

(Deep breath... )

The volume pot reads 6K from terminal 1 to 3 because the switch was in either position 4 or 5 when you measured it - you're seeing the pickup resistance, which is in parallel with it.

To check it's working properly, measure from ground to the middle terminal while slowly turning it from 0 up to 10. Keep the pull-switch down (off) and the pickup selector in the bridge position (humbucker) so the 470K resistor is disconnected.

What you should find is that the resistance starts at 0, reaches a peak of about 125K when the knob is at 7 or 8, then falls back to 16K(ish) at 10.

Hahah I've never used that term before and don't know what came over me as I actually have the same gripe!
Will edit immediately and pretend it never happened.

Re the pot checks, on the volume I'm getting no reading from the middle terminal to ground, same with the tone pot 1 (no matter how I rotate the knobs). On tone pot 2, I'm getting 16.2K (unaffected by rotating the knob).

ICBM

This sounds like a bad ground connection.

The 16K from the humbucker tone pot to ground is correct, that’s the pickup resistance again. You should be reading roughly 6K in positions 3 and 5 (or 3K in position 4) on the single coil tone control, and the volume control/ground resistance should go to zero when the knob is.

Johnny333

Thanks @ICBM How would I check for a bad ground connection and fix it? Once again, apologies for being such a newbie to all this, hugely appreciate your help!

ICBM

Use the multimeter to check for continuity between the jack ground and all other grounded points. It’s slightly confusing that you’ve got the colour coding the wrong way round on the jack wires, but as far as I can see they do actually go to the right places .

Where do the middle and neck pickup ground wires go to?

Johnny333

ICBM said:

Use the multimeter to check for continuity between the jack ground and all other grounded points. It’s slightly confusing that you’ve got the colour coding the wrong way round on the jack wires, but as far as I can see they do actually go to the right places .

Where do the middle and neck pickup ground wires go to?

Just checked the following grounds to the jack ground: volume, tone 1, tone 2, 5-way switch, pickguard shielding, and all are showing continuity. 

The neck pickup ground goes to tone pot 1 and the middle pickup ground goes to the volume pot. Is that ok?

Funkfingers

.

ICBM

Johnny333 said:

Just checked the following grounds to the jack ground: volume, tone 1, tone 2, 5-way switch, pickguard shielding, and all are showing continuity. 

The neck pickup ground goes to tone pot 1 and the middle pickup ground goes to the volume pot. Is that ok?

It's much better to ground all the pickups to the volume pot. That doesn't sound like the problem if you're getting continuity though.

This is becoming troublesome...

What I would do given this problem is to temporarily disconnect everything except the jack, volume pot, and the pickup side of the switch. You don't need to actually remove everything else, just undo the link from the volume to the tone side of the switch. (Personally, I would turn the switch round while you’re doing this as well - it’s not ‘wrong’ as it is but it isn’t ‘right’ either.)

If you've got all the pickups and the jack grounded to the volume pot, nothing else is in the circuit, and the single coils are still too quiet compared to the humbucker, then the problem is either a faulty switch (unlikely if it affects two positions, but possible) or the single coil pickups (also rare, especially for two at the same time), but it is possible.

Johnny333

Thanks @ICBM So just to clarify, am I disconnecting the wire crossed in blue and reconnecting the neck pickup ground from the tone 1 pot to the volume pot? Then tap testing the pickups?

ICBM

Disconnect that wire at the volume control, and the one from 4 to 5 on the switch at the 5 end - and to be on the safe side, the one from 5 on the 5-way to 10 on the pull-switch as well. Connect 5 on the 5-way to 1 on the volume (you could use the pull-switch one to temporarily do that without unsoldering it at the 5-way end).

That will give you purely a 3-pickup guitar with no complications. If the singles are grounded to the volume pot and still quiet, it's either the switch or the pickups.

In cases of baffling problems, reduce the circuit to the minimum level of complexity and start from there, it saves a lot of guesswork and trial and error.

Johnny333

Thanks again @ICBM I've just tried this and am getting the same results: quiet humbucker and even quieter single coils. So I guess that narrows it down?!

Could it also be an issue with the volume pot? And is there a way I can test this without replacing it?

ICBM

Johnny333 said:

Could it also be an issue with the volume pot? And is there a way I can test this without replacing it?

Simply connect the jack directly to the switch terminal 5 with the pot out of the circuit. If you get a lot more volume - a little is expected, but if it’s dramatically different - then the pot is faulty. This wouldn’t explain the singles being so much quieter than the humbucker though.

Johnny333

ICBM said:

Johnny333 said:

Could it also be an issue with the volume pot? And is there a way I can test this without replacing it?

Simply connect the jack directly to the switch terminal 5 with the pot out of the circuit. If you get a lot more volume - a little is expected, but if it’s dramatically different - then the pot is faulty. This wouldn’t explain the singles being so much quieter than the humbucker though.

We have sound! Seems to be working now so I guess it must be the volume pot? Will wait for your reply but assuming I should replace that and wire up as before?

ICBM

Johnny333 said:

We have sound! Seems to be working now so I guess it must be the volume pot? Will wait for your reply but assuming I should replace that and wire up as before?

Yes - it sounds like the volume pot may be partially shorted, which is loading the pickups much too heavily, but the higher-output humbucker is coping better.

I would take it in stages if you can be bothered - pickups, switch, volume pot first, then test. If that works OK then connect the tone controls and test. If that all works, then connect the pull-switch/resistor wiring.

Johnny333

@ICBM  I still don't know your name, but thank you so much for your amazing patience and help with this. I'm delighted to announce that we finally did it! 

Turns out it was the volume pot so I swapped it out with a new one and all is working now!

(Minus some grounding issues but I can probably figure that out!) Thanks so much and to everyone else who got involve in this mess! I finally got the chance to hear the first guitar I've ever built so it was a real treat

ICBM

Johnny333 said:

@ICBM  I still don't know your name, but thank you so much for your amazing patience and help with this. I'm delighted to announce that we finally did it!

John .

I used to do this sort of thing for a living - it’s a bit easier with experience. This one was a bit of an odd one since a few of the symptoms didn’t seem to quite add up, but it’s still just a matter of logic and eliminating possibilities until you get there!

That confirms what I suspected at the last stage - a partial short in the volume pot, not complete enough to silence the whole thing, but loading the pickups far too heavily… that’s quite unusual.

There’s always a real feeling of achievement when you finally solve a tricky problem like this, I can only imagine it must be more so when it’s the first guitar you’ve had to do it on .

Johnny333

ICBM said:

Johnny333 said:

@ICBM  I still don't know your name, but thank you so much for your amazing patience and help with this. I'm delighted to announce that we finally did it!

John .

I used to do this sort of thing for a living - it’s a bit easier with experience. This one was a bit of an odd one since a few of the symptoms didn’t seem to quite add up, but it’s still just a matter of logic and eliminating possibilities until you get there!

That confirms what I suspected at the last stage - a partial short in the volume pot, not complete enough to silence the whole thing, but loading the pickups far too heavily… that’s quite unusual.

There’s always a real feeling of achievement when you finally solve a tricky problem like this, I can only imagine it must be more so when it’s the first guitar you’ve had to do it on .

Thanks again John, it was extremely satisfying to finally figure it out! Hope to chat again soon.