L5ces Volume Knob Won't Turn Completely Down

[lawson-stone]

My L5ces neck pickup volume knob will not turn the volume all the way down. When the knob is fully rotated, it's still easily the equivalent of setting it on 3 or 4. The pot is not scratchy, I have no hum or other noises.

I snapped this picture of the pot which though somewhat unfocused might offer a clue.

Any advice is appreciated.

[Tal_175]

A diagnostic question: when in neck position do bridge controls still work? Does the volume go completely down if bridge volume is down?

[lawson-stone]

A diagnostic question: when in neck position do bridge controls still work? Does the volume completely down if bridge volume is down?

Bridge pickup works exactly like it is supposed to. When the neck is on, bridge controls have no effect on the sound. When "both" are on, each one reduces the volume. Bridge all the way down, neck only part way. There's no cross-over between the neck and bridge controls.

[wintermoon]

The guitar is unrepairable, just send it to me.

But check the grounding wire on the pot to make sure it's well soldered.

[sgosnell]

It's a wiring issue, I'd bet on it. But I can't say precisely what the issue is without inspecting it.

[rpjazzguitar]

Put an alligator clip on the bent lug and connect the other end to ground. If that solves the problem, heat the solder on the bent lug.

[Dave70]

Try turning all the knobs to off, including tone and see if the volume goes off... On one of my guitars I took apart and put back, I must have pressed one of the wires so it touched another point in the circuit and my TONE was acting like a volume! lol

[KirkP]

As suggested earlier, this does seem like a disconnected ground on the volume pot. Here’s where that would be on the schematic.

It looks like this connection was made by bending the pot terminal and soldering to the case. So it might be a poor solder joint.

It can be resoldered, but there is some technique involved in getting it hot enough to overcome the heat sink of the case without getting it so hot that you damage something.

It’s conceivable that instead of a bad solder joint that the ground terminal of the pot has lost its internal connection. In that case the pot would probably need to be replaced. It seems unlikely though.

[KirkP]

I thought of another diagnostic. Connect an ohmmeter between the center terminal of the volume pot and each of the ground points I’ve circled in red (one at a time). Rotate the pot over the full range. It should measure near zero when the pot is set to minimum. Measuring at all three locations may give you a clue where the bad ground connection is.

[deacon Mark]

I thought of another diagnostic. Connect an ohmmeter between the center terminal of the volume pot and each of the ground points I’ve circled in red (one at a time). Rotate the pot over the full range. It should measure near zero when the pot is set to minimum. Measuring at all three locations may give you a clue where the bad ground connection is.

Plus 1 on this do this first. Good thinking.

[lawson-stone]

Thanks for these suggestions. I"ve been working at it, but unfortunately it's very hard to get a clear shot at a connection to the terminals of the pot. I even tried to pull the pot out through the bridge pickup opening but the lead connecting the volume to the tone pot would not allow it. At any rate, I got the right readings on those points noted above. The one I am in doubt about is the center-to-braided cable. I could not be absolutely sure I had the right cable and that it was not crossed over another.

Now I'm wondering though, maybe the ground problem is through the switch?

What I'm thinking also is that this is the only disappointment I have in this L5, and it's quite bearable. I'm just OCD about things working exactly as they are supposed to, so this bugs me. Otherwise, though, it might not be worth the attempt to fix it.

[wintermoon]

If you have to fish the entire harness out set aside a bit of time. It's a major pain in the keister.

[Longways to Go]

considering how "unfun" it is to fish electronics in & out of f-holes, why not just send it to a shop?

[Tal_175]

Archtops with electronics should have bolt-on tops, not glued

[lawson-stone]

considering how "unfun" it is to fish electronics in & out of f-holes, why not just send it to a shop?

I don't know what shop near me I'd use, I don't want to ship the guitar unnecessarily, and I don't want to be away from the guitar any length of time unless it's a much more serious problem.

I'd hoped maybe the solution would be something I could do myself without a lot of drama. I'm wondering if it's maybe related to the switch? But since the guitar otherwise is wonderful, I don't think I want to send it out.

[KirkP]

Now I'm wondering though, maybe the ground problem is through the switch?

I don’t think so, since according to the schematic the switch isn’t connected to ground. Its metal shell might be grounded, but that’s not part of the circuit so would only be grounded in the general practice of grounding everything metal.

Don’t give up on it yet. Here’s another easy experiment. Put an instrument cable in the guitar and an ohmmeter between the tip and sleeve. Switch to the neck pickup and write down the readings with the pot at max and min. You’ll need to switch your ohmmeter ranges to get the high and low numbers accurately. Now switch to the bridge and do the same. At maximum volume the impedances should both read pretty high (something like 50K ohms?). At minimum volume both should be very low (more like 30 ohms?). Those four resistance readings might give us a clue.

[lawson-stone]

I don’t think so, since according to the schematic the switch isn’t connected to ground. Its metal shell might be grounded, but that’s not part of the circuit so would only be grounded in the general practice of grounding everything metal.

Don’t give up on it yet. Here’s another easy experiment. Put an instrument cable in the guitar and an ohmmeter between the tip and sleeve. Switch to the neck pickup and write down the readings with the pot at max and min. Now switch to the bridge and do the same. At maximum volume the impedances should both read pretty high. At minimum volume both should be very low. Those four resistance readings might give us a clue.

This was odd. At "10" the neck reading, with the meter set to read the 200k range, it starts at 8.0. As I turn down to about 9 or 8 it reads 105 then 157 and goes down to stop at 77.4 or so at 1. I have no idea whats up with that reading. If I set the range to 20k it starts at 7.9 and almost immediately, as I turn to 8 or 9, it reads 1.

Bridge starts at 8.4 and drops to near zero. Maybe tomorrow I do a video showing what they do. I don't get how the ranging on this meter is to be read.

[Jimmy Mack]

I once bought a Gibson '57 RI Les Paul Custom. Fancy right? The friggin volume pots on that guitar were sh*t. They didn't work right, and then just totally stopped working. Nice! Pulled them out and they were 300K and 250K ohms, but totally unusable. So, you are stuck on a goose-chase. Replacing my pots helped the tone of the guitar as well (500K).

Good luck and enjoy the guitar!

[KirkP]

This was odd. At "10" the neck reading, with the meter set to read the 200k range, it starts at 8.0. As I turn down to about 9 or 8 it reads 105 then 157 and goes down to stop at 77.4 or so at 1. I have no idea whats up with that reading. If I set the range to 20k it starts at 7.9 and almost immediately, as I turn to 8 or 9, it reads 1.

Bridge starts at 8.4 and drops to near zero. Maybe tomorrow I do a video showing what they do. I don't get how the ranging on this meter is to be read.

I just ran the same experiment on a Telecaster. I was surprised by the in between behavior at first, but looking at the schematic again it makes sense. The resistance of the pot is much higher than the pickup, so at the maximum position your reading is mostly from the pickup. At minimum position you are reading the minimum resistance of your pot. If you calculated resistances at between positions (which I didn’t) the resistance measured at the jack actually should go higher, as we both observed.

The “1” reading on a digital ohmmeter just means you were out of range. It’s telling you to switch the ohmmeter to another range for an accurate measurement. Try measuring the minimum pot positions for both pickups again with the ohmmeter set to the minimum range. If it reads “1” on the the neck pickup, keep increasing the range until you get a good number. It’s the minimum pot positions we are really concerned about here.

Based on your report so far, it looks like your neck pot measured 77.4K ohms at the minimum position. If so, that’s way too high, and would explain your symptoms.

Hey, I wonder if it’s possible that something is mechanically preventing your neck pot from turning all the way down? It seems unlikely, but it’s conceivable that a foreign object in the pot it jamming up the works. Do the two volume pots feel the same as you rotate end to end, and rotate the same number of degrees?

[sgosnell]

You need to set the range above 200k, because the pot has a higher resistance than that. It's probably a 500k pot, certainly at least 300k, so you need to set the range above that to get an accurate reading. I don't know what ranges you have on your meter, but it should have something higher. If not, you're wasting your time.

[KirkP]

You need to set the range above 200k, because the pot has a higher resistance than that. It's probably a 500k pot, certainly at least 300k, so you need to set the range above that to get an accurate reading. I don't know what ranges you have on your meter, but it should have something higher. If not, you're wasting your time.

For these measurements, we’re mostly interested in hat happens when the pot approaches the minimum. For that, the ohmmeter would be set to a low range.

I also suggested measuring with the pots set for maximum. Since the pot is in parallel with the pickup, the measured resistance will be close to the pickup’s, which should be much less than 20K ohms.

Only for intermediate positions of the pot does the resistance at the jack exceed 20K ohms. Knowing those values won’t help diagnose this problem so I didn’t ask for them.

[lawson-stone]

I just ran the same experiment on a Telecaster. I was surprised by the in between behavior at first, but looking at the schematic again it makes sense. The resistance of the pot is much higher than the pickup, so at the maximum position your reading is mostly from the pickup. At minimum position you are reading the minimum resistance of your pot. If you calculated resistances at between positions (which I didn’t) the resistance measured at the jack actually should go higher, as we both observed.

The “1” reading on a digital ohmmeter just means you were out of range. It’s telling you to switch the ohmmeter to another range for an accurate measurement. Try measuring the minimum pot positions for both pickups again with the ohmmeter set to the minimum range. If it reads “1” on the the neck pickup, keep increasing the range until you get a good number. It’s the minimum pot positions we are really concerned about here.

Based on your report so far, it looks like your neck pot measured 77.4K ohms at the minimum position. If so, that’s way too high, and would explain your symptoms.

Hey, I wonder if it’s possible that something is mechanically preventing your neck pot from turning all the way down? It seems unlikely, but it’s conceivable that a foreign object in the pot it jamming up the works. Do the two volume pots feel the same as you rotate end to end, and rotate the same number of degrees?

Thanks. I get the ranging issue and why the reading is doing what it's doing so that's cool.

There's no problem with the movement of the knob. It has the same range as the bridge pickup.

The one thing I have not had a chance to eyeball directly is that bent back tab on the pot. I think I got a reading yesterday but the angle was not one that gave me certainty about that. I"m nervous about contorting the pot so much that I mess up the tone pot connections as well.

[lawson-stone]

You need to set the range above 200k, because the pot has a higher resistance than that. It's probably a 500k pot, certainly at least 300k, so you need to set the range above that to get an accurate reading. I don't know what ranges you have on your meter, but it should have something higher. If not, you're wasting your time.

The stock volume pot on this is, I think, a 300K.

[KirkP]

This was odd. At "10" the neck reading, with the meter set to read the 200k range, it starts at 8.0. As I turn down to about 9 or 8 it reads 105 then 157 and goes down to stop at 77.4 or so at 1.

Since the resistance goes down as the pot nears minimum rotation, we at least know that the pot is making a connection to ground, but a poor connection. Some potential causes:
1. Poor solder joint between the ground terminal and case;
2. A poor connection between the ground terminal and the resistor internal to the pot.

3. Something mechanically interfering with full minimum rotation of the pot.
Can anyone think of other possible causes consistent with the schematic?

[John A.]

The stock volume pot on this is, I think, a 300K.

Perhaps a stupid question, but have your tried cleaning the pot? The problem could be something with the mechanics of the pot. If you can access the back of the pot, try spraying DeOxit D5 in the little hole there. Otherwise, try dripping some down the pot shaft.


John