Jazzmaster Lead Circuit No Output

[camilonava27]

I have this MIJ CAR JM66 that for some reason does not have any output when in the lead circuit. The rhythm circuit works perfectly fine, but as soon as I switch down to lead, theres no sound. Could it be a faulty pickup or connection?

https://imgur.com/gallery/scSDwDa

[HarktheUmpire]

I find it’s impossible to tell from the photos. It’s definitely been completely redone at some point; looks like all the wiring was replaced. Pots too. And probably the pickups. Not necessarily a bad thing. When there’s no sound in some position, I normally assume there’s a full circuit somewhere, or whatever that’s called; lead making contact with ground and cancelling out the signal. But I can’t tell from these pictures.

Can you take a close-up picture of the wiring at the lead/rhythm switch? And take one of the pickup switch too please; I think the source of the problem is most likely there. Maybe disentangle things a bit if possible before taking pics.

Some questions: Where is the lead wire of the bridge pickup going? Do you know if there’s shielding paint in the cavities? Was this a sudden occurrence, does it happen intermittently, or is it a new/recent thing?

[camilonava27]

I find it’s impossible to tell from the photos. It’s definitely been completely redone at some point; looks like all the wiring was replaced. Pots too. And probably the pickups. Not necessarily a bad thing. When there’s no sound in some position, I normally assume there’s a full circuit somewhere, or whatever that’s called; lead making contact with ground and cancelling out the signal. But I can’t tell from these pictures.

Can you take a close-up picture of the wiring at the lead/rhythm switch? And take one of the pickup switch too please; I think the source of the problem is most likely there. Maybe disentangle things a bit if possible before taking pics.

Some questions: Where is the lead wire of the bridge pickup going? Do you know if there’s shielding paint in the cavities? Was this a sudden occurrence, does it happen intermittently, or is it a new/recent thing?

Lead wire of the bridge pickup is going to the toggle and there's no shielding in the cavities. I've been having these issues since I got the guitar a year or two ago. At first it didn't bother me because I almost alway play on the Rhythm circuit on JMs, but the guitar hasn't been getting much use for quite sometime. I added some more pictures that are hopefully more helpful.

https://imgur.com/gallery/BLPUbVu

Thanks for the help!

[timtam]

Yeah it's been re-wired, and not very well. First thing that jumped out at me in the pics was all the untrimmed wire at the terminals on the switch and the pots. Prime opportunity for shorts. So I would first go through with some wire snippers and cut off all the bare wire ends sticking out from the solder. And first time I fired up the soldering iron I'd be putting insulation on the cap legs. You can never tell what gets pushed together when cramming everything back into the cavities. Overall this has the air of the too-common re-wires of Japanese offsets based on the false assumption that "(shielded)Japanese wiring = bad / vintage-style cloth wire = good". In fact it's the other way round (shielded wire = better). Pickup swaps are reasonable; wire, pots and switches don't need replacing unless they are malfunctioning.

The key to further trouble-shooting is understanding the circuit (see below). Because the symptoms then point you to the only likely locations where the problem may be arising. In JMs and jags, the rhythm and lead circuits are largely independent. So if the problem is only in the (whole) lead circuit, that points to the independent part of that circuit (toggle->lead controls->lead/rhythm switch).

Hard to tell for sure from the pics of the toggle switch, but it looks like the output of the toggle may be wired to ground (volume pot body) rather than to the left tab of the volume pot (as it should be). That is, there appears to be no route from the pickups to the controls (and therefore to the output).

[andy_tchp]

Unless I'm missing something and/or it's a trick of the photo, there is literally nothing connected to the output of the 3-way switch.

This is your 'lead' circuit and it's not going anywhere.

(And +1 to every one of timtam's comments.)

[timtam]

Unless I'm missing something and/or it's a trick of the photo, there is literally nothing connected to the output of the 3-way switch.

This is your 'lead' circuit and it's not going anywhere.

Yes, indeed that's the other possible mis-wiring of the toggle switch - that the switch output is not connected at all at the switch end (or wired to ground as I suggested). There's definitely no connection at the other end - to the left volume pot tab (from the switch output) - as there should be. Messing up that toggle is a common wiring error.

[HarktheUmpire]

Unless I'm missing something and/or it's a trick of the photo, there is literally nothing connected to the output of the 3-way switch.

This is your 'lead' circuit and it's not going anywhere.

Yes, indeed that's the other possible mis-wiring of the toggle switch - that the switch output is not connected at all at the switch end (or wired to ground as I suggested). There's definitely no connection at the other end - to the left volume pot tab (from the switch output) - as there should be. Messing up that toggle is a common wiring error.

+1

I messed that up myself once, which is why I wrote that I suspect the problem is most likely there.