Grrrr! Wiring Woes

BillDL · August 2023

This should probably be in the "vent your spleen" thread, but there's a question at the end.

I have an 80s 2x HB guitar with 2x vol, 2 x tone to rewire with new pots and switch. The control cavity is quite tight and the drilled holes from the control cavity through the pickup routs to the switch cavity are fairly small diameter. Ordinarily I would have used single core with external braid wire, but it was all very tight through the holes and there is a tenon in the bridge neck HB cavity taking up some space, so I ordered some plastic sheathed cable with internal braid earth while I was ordering other parts. They only had twin insulated conductor and internal braid screen, but it was narrow enough in diameter for the cables to pass through the holes and flexible enough to route well in the obstructed neck pickup cavity. I just folded the unused insulated core back out the way with shrink tubing.

All completed and ready to drop the whole assembly down into the control cavity, but I did a test before doing so. Switch wasn't working on one side apparently, so I checked all the connections on the switch, pots, etc, for bad connections and dry solder joints and started doing continuity tests. It turns out that I have two cables in the guitar in which there is a discontinuation of the core I chose to use as the live, or else a break in the insulation. The cable was bought as 2 x 1m lengths, with 2 lengths being cut from one piece and a 3rd cut from the 2nd piece. The leftover bit from the 2nd piece of cable has fine conductivity / continuity on both conductors and braid, as does the piece cut from it that I used in the loom. Both pieces cut from the 1st length of cable have the same fault.

I've never had this before with multi-conductor shielded cable. It is the type that has a wrapped braid screen as well as the very thin metallic foil wrapped around inside. Yes, the core wires are pretty thin and more fiddly to work with than the cloth push-back wire inside externally braided cable, but it's not my connections. One core is definitely faulty and there is zero electrical continuityy. I'll have to strip all the wiring back out and start from scratch with different wire, or else try and bore the conduit holes between the cavities larger to accommodate thicker braided cable. That's several hours down the drain due to one piece of cable, and the fact that I never thought to do a continuity test on the cable before soldering it all in place. I'm really pissed off to say the least.

Has anybody else ever had a dodgy length of plastic sheathed multicore cable with internal braid screen?

ICBM · August 2023

If you have an unused core in the faulty cable, use the other one.

BillDL · August 2023

I'm not altogether sure that I trust the cable, however I will lift out the pickups, pull some of the slack cable through and rewire the switch, volume pot and jack socket using the other conductor. I like to use heatshrink tubing over the contacts and it's a pain in the tits peeling it off and stripping back sheathing while in situ. I packed all my stuff away in disgust yesterday, but I've calmed down now.

ICBM · August 2023

Is this a Gordon-Smith guitar by any chance?

SteveRobinson · August 2023

Exactly what I thought. John Smith told me that he liked to leave as much wood as possible "for the tone"

WezV · August 2023

depending on how things line up, it might be best to drill all the way from jack socket to switch cavity with a larger diameter drill bit. it's a scary job, but sometimes necessary

BillDL · August 2023

It's not entirely dissimilar to a Gordon Smith in design, but with the toggle switch on the upper horn. The guitar is the vaguely "SG-ish" short asymetric pointy-horned Westbury Standard like this. I've spent a while today with the small drum sander bit on a Dremel widening the switch cavity to accommodate an open-frame 3-way switch (dodgy enclosed box switch was stock) and cables without changing the diameter of the circular cover plate recess, and I widened the conduit hole from there to the neck pickup rout by hand from both sides at different angles with a short 11mm drill bit on an improvised tap wrench. I've also managed to ream out the other conduit holes between the pickup routs and through to the control cavity with a large stubby centering spot drill bit (CNC type) and a ratchet socket handle. The angles weren't conducive to confidently using a long drill bit in an electric drill, and I don't have a right-angled drill or Dremel attachment. The conduits are now large enough to freely draw externally braided single conductor cables through, so for all this has been a pain in the arse, I can now confidently wire it with good cable.

Lesson learned. Do continuity tests on wires before soldering in place and do continuity tests on each wire after soldering.

Funkfingers · August 2023

ICBM said:

Is this a Gordon-Smith guitar by any chance?

SteveRobinson said:

Exactly what I thought. John Smith told me that he liked to leave as much wood as possible "for the tone"

Medical forceps required to work in the control cavities of those buggers!

A GS1 control cavity has adequate space for two pots and a jack socket. The GS1½/GS2 cavity is only marginally larger. It would help repairers if G-S left more slack in the pickup and output cable runs.

BillDL · August 2023

Agreed. This isn't quite as cramped and no forceps actually required, given that I invariably assemble the main part of the control cavity loom on a plywood template outside the guitar, but the opposing solder lugs of the pots are close enough that the legs on a 0.022 uF "orange drop" capacitor have to be bent inwards to solder them between vol and tone pots, so I will probably just solder a small green or brown mylar from lug to pot casing to leave space for the incoming and outgoing cables.

BillDL · August 2023

Got it all wired up with new cable and good pots, tested successfully, and closed up the back. Started pushing on knobs and the third one gave a little bit more resistance than the first two and then suddenly popped down. Realised I had pushed the casing off the back of the pot. I wasn't pressing much harder than normal, but neither was I pressing against the back of the pot while pushing on the knobs. Turns out I had an 18-spline knob mixed in with three 24-spline knobs and was trying to push it onto a 24-spline pot. Never managed to to this before. Will try and solder in a new knob without removing the other pots and hope I don't melt other wires. Really pissed off at my stupidity.

roberty · August 2023

Oof sounds like a nightmare

paulnb57 · August 2023

Ive done the same Bill, final job, pop the pots on, the back of the pot pushed off…that was on an Epi Semi, where everything had to go through the f holes..oh the joy

BillDL · August 2023

paulnb57 said:

Ive done the same Bill, final job, pop the pots on, the back of the pot pushed off…that was on an Epi Semi, where everything had to go through the f holes..oh the joy

Glad to know it's happened to somebody else, and I don't mean that in a sarcastic way. I was kicking myself for making such a rushed elementary error, but if it's happened to others I feel a bit less idiotic. With semi-acoustics I normally reach through the F-Hole with a finger and push up against the pots that can be reached to support them as I push on the knobs (for support to the top as well as the pot), and I always test fit them before I finally install the loom, so thankfully no mishaps with semis.

WezV · August 2023

I've had it a few times with newer CTS.

It's because some sellers now sell CTS pots without the important circlip that stops it happening.

BillDL · August 2023

WezV said:

It's because some sellers now sell CTS pots without the important circlip that stops it happening.

"Circlip"? I'll have to have a much closer look at some of my older pots. I know I've seen a circlip just below the screwed shaft tip of some toggle switches, presumably to stop you overwinding the switch tip, but I have never been aware of a circlip on old pots, and it makes absolute sense when thinking about how easily the tabs of the can bent and allowed the back of that pot to push right off. Is the shaft clip internally fitted, or is it visible externally? On an older pot I think I'm seeing an extra circle of metal just down inside the threaded collar, between the metal of the collar and the shaft of the pot, but I can't be sure.

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