Fender Japan Traditional 60's Jazzmaster (re)wiring help

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zaffa
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Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by zaffa » Mon Aug 05, 2019 2:20 am

Hi, I recently got a lefthanded Fender Japan Traditional 60's Jazzmaster. Lefty ones were available for pre-order only in July 2018, here's a spec if anyone's interested:

https://www.leftyguitars.be/en/electric ... -1095-eur/

I opened it up, and a few things seemed interesting to me:
  • both volume and tone pots in the lead circuit are 1Meg audio taper
  • it's got US-made electronic components (CTS, Switchraft), while the pickups are still the usual MIJ affair - here's a comparison of the stock pickup (on the left) and SD Antiquity for JM (right)
Image


Since Fender reverse wires their pots on lefty guitars, I was planning to un-reverse the wiring in order to regain the full function of the audio tapers (reverse wired they basically act like an on-off) but I am a bit confused by how they are currently wired:

Image

Image

And a link to the album where you can open images in higher res: https://imgur.com/a/6E5W56F

I've compared this to traditional JM wiring diagrams and these connections seem a bit off (and I don't mean just the reverse wiring which I expected to see). I didn't trace all the cables, but even the wires between the two pots don't seem to match what I was expecting from the wiring diagram (eg. the capacitor connection between the two pots). Can anyone who has more experience with JM wiring take a quick look and confirm if everything's OK? I can provide more gut shots if necessary.

Here's the wiring diagram I looked at:

Image

Thanks!

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by timtam » Mon Aug 05, 2019 4:34 am

Firstly, that's a really nice wiring job - shielded cable everywhere. Better than most US ones.

There are functionally equivalent variations in things like capacitor wiring in some Fender guitars, such as how the cap's grounding is wired. With the left-handed pot thing and the pictures of the pots not being 100% clear on what is grounded, it is not clear to me whether or not yours has a functionally different variation. Also, with the grounds having to run with the conductors in shielded cable, there will be instances where the ground wires elsewhere in the guitar have to take somewhat different routes, without affecting function.

Anyway you could trace it out and then compare to vintage wiring as in the AVRI65 for example ...
https://www.fmicassets.com/Damroot/Orig ... A_SISD.pdf

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by 601210 » Mon Aug 05, 2019 5:05 am

timtam wrote:
Mon Aug 05, 2019 4:34 am
Firstly, that's a really nice wiring job - shielded cable everywhere. Better than most US ones.
It seems like Fender Japan are really upping their game (maybe they read an OSG thread or two recently :whistle: ). Almost all the new stuff they've been putting out have had pretty good electronics, some of the new JMs even have PV65 pickups. Unfortunately the prices are following suit a little bit.

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by zaffa » Mon Aug 05, 2019 12:29 pm

Focusing on the lead circuit pots, here's what I would expect to see (having in mind reverse wiring of the pots):

Image

and here's the trace:

Image

It seems to me like the wiring of the two tone pot lugs is wrong, but any help from more electronics savvy forum members is much appreciated.

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by timtam » Mon Aug 05, 2019 6:58 pm

Looks like they've wired the main (lead) controls 'modern' style rather than vintage JM ....
https://www.premierguitar.com/articles/ ... a-tone-pot

The American Special and Am Pro are also wired that way ...
http://www.fmicassets.com/Damroot/Origi ... A_SISD.pdf
https://www.fmicassets.com/Damroot/Orig ... 7-2016.pdf (Am Pro also has treble bleed)
Possibly other non-vintage-style JMs too but I haven't checked.

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by zaffa » Mon Aug 05, 2019 10:29 pm

Very interesting reading. So it seems I'm good to go to just reverse the wiring of the outer lugs. Thanks!

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by zaffa » Tue Aug 06, 2019 12:32 am

Another question to avoid opening a new topic - grounding on the guitar is done over the tremolo plate. I've removed the plate in order to replace the stock trem with Staytrem and now I've got some constant hum which I suspect is due to the grounding.

Originally the ground wire was wrapped around this mounting screw (not sure whether it was in contact with it):

Image

My question is - should the ground wire touch both the tremolo plate and the tremolo plate mounting screw or it's supposed to have contact only with the trem plate?

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by 601210 » Tue Aug 06, 2019 1:24 am

If it touches one it touches both, right? Maybe it just fell out when you screwed it back in?

You could check the connectivity between the vibrato plate and your output jack to be sure.

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by alexpigment » Tue Aug 06, 2019 9:53 am

timtam wrote:
Mon Aug 05, 2019 6:58 pm
Looks like they've wired the main (lead) controls 'modern' style rather than vintage JM ....
https://www.premierguitar.com/articles/ ... a-tone-pot

The American Special and Am Pro are also wired that way ...
http://www.fmicassets.com/Damroot/Origi ... A_SISD.pdf
https://www.fmicassets.com/Damroot/Orig ... 7-2016.pdf (Am Pro also has treble bleed)
Possibly other non-vintage-style JMs too but I haven't checked.
Honestly, I don't know why 50's wiring isn't standard. The benefit is that you don't lose any highs when you roll down the volume, so the volume becomes way more useful as a tool. Rolling down the tone below 10 slightly decreases your volume (or gain, depending on your signal chain), but I would think most people are actively messing with their volume knob way more than their tone knob. At any rate, changing to 50's wiring is the first thing I do on any guitar.

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by zaffa » Wed Aug 07, 2019 6:27 am

Just an update - there was hum in the middle pickup switch position (althought the pickups are RWRP) and crackling present whenever I touched the tremolo arm. So I removed the tremolo plate, positioned the ground wire so that it doesn't touch the screw and the screwed the tremolo plate back again, and everything is fine now. Not sure if crackling was due to the wire touching the screw or the plate not being fixed firmly onto the body, but the crackling is gone.

As for the hum in the middle position, I found out that it's gone whenever I touch the tremolo plate. The guitar doesn't have any strings on now, so the hum will go away as soon as I restring it. You learn something new every day ::)

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by alexpigment » Wed Aug 07, 2019 8:14 pm

zaffa wrote:
Wed Aug 07, 2019 6:27 am
As for the hum in the middle position, I found out that it's gone whenever I touch the tremolo plate. The guitar doesn't have any strings on now, so the hum will go away as soon as I restring it. You learn something new every day ::)
Are you implying that the hum will go away because you'll be touching the strings? If so, I still say there's a ground problem somewhere. Despite some posts I've read in the past that consider this "normal", I don't think I've ever had a properly wired guitar that exhibited this behavior. Out of curiosity, does your amplifier have a 3-prong (grounded) cable into the wall socket?

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by zaffa » Mon Aug 26, 2019 1:42 am

Hey, sorry for the misinformation. It seems that the grounding cable connection was bad so I resoldered it and rewired the guitar and everything's fine and silent.

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by JAGJazz » Mon Oct 21, 2019 12:42 pm

Slightly off topic: the stock pickups were basically Strat pickups with larger JM bobbins? Thanks

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Re: Fender Japan Traditional 60's Jazzmaster (re)wiring help

Post by beefyburt » Wed Jun 24, 2020 2:34 am

Hey. So did you sort the wiring out so it now works gradually? I've just bought a 2016 MIJ Jazzmaster, and of course the tone is with on or off, and the volume is gradual up to 9, then it's a big jump to 10. Did you swap over some of the wiring to the volume and tone pots? Cheers.

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