The Jazz Guitar Chord Dictionary
  1. #1

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    Yesterday was an interesting experience.
    For the first time I replaced a wiring harness and pickups by myself.
    Not on a Tele, LP or Strat. Or something sensible with a rear access plate.
    Not a hollow body with a nice large aperture left by top mounted pickups,

    But a semi hollow. A 335 may have been an easier first go but no- we own a 339. The 14” baby sister of the 335.

    that’s right- first attempt to rewire a harness and do pickups at the same time on the most congested room possible.

    so yeah I feel like I graduated into something.

    Best tip I can give- the right tools will save your sanity. I used a music stand light (mighty light) to fit inside the the f-hole to illuminate the cavity. A dental mirror to look around and assess with good light- and an 8” pair of skinny spring closed (squeeze to open) tweezers. Without these it would have taken 2 days and a lot of frustration.

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    The Jazz Guitar Chord Dictionary
     
  3. #2

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    Would I do it again- sure.
    what would I do different next time?
    1/ insulate the braid out side of the pickups if not already so. I found when fully assembled the braid would sometimes touch the signal side of the selector switch and dump all signal to ground. I used electrical tape this time rather than disassemble/ reassemble.
    2/ CTS pots are sometimes taller than stock. They come with a locknut and star washer. I saw a tip where the height got established outside the guitar (a 335) and they suggested a spot of cca glue to hold it and the washer in place before insertion. First Check your pot can still fit through the f-hole this way. Mine did not. I had to scrape all the superglue off and try again. It is a Chinese puzzle to get it to fit in as is. Putting on the locknut and starwheel once inside was not that hard anyway. I could have shaved an hour had I known.
    3/ on the 339 specifically the jack is on the outside of the lower bout edge. It is a thin body depth guitar. The jack spring for the plug centre and the tone pot for bridge PU get awfully close and can actually interfere with each other if the jack orientation is positioned poorly. Use a mirror to twist the jack (carefully) so that the plug will not push the spring against the pot’s housing and dump your signal to ground.

    those three learnings aside- here are some other things I would suggest-
    Last edited by EastwoodMike; 12-22-2021 at 03:06 AM.

  4. #3

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    Useful stuff-
    1/ blue painters tape is your friend. Protect your f hole perimeter with it. Saves on varnish coming off.
    2/ whole guitar on a towel, neck supported, and a cloth over the body. You may move the guitar around more than you’d expect and the cloth will stop the wiring harness leaving a momento on your finish.
    3/ take note of what screws went into what pickup ring and the orientation of then. I dunno about an LP or Fender, but the 339 top is curved enough that both PU rings are tapered and are both different thickness. Rookie mistake not paying attention first time.
    4/ I used PVC tubing help get the pots into position. Once in the cavity and with locknut and washer in place, thread the tube through the intended hole, pull through a length with your tweezers and then press the end onto the pot shaft. I sized the tubing so that the external washer and lock nut slipped over the tubing once the pot is in position.
    5/ order- I went jack, selector, NK T, NK V, BR V and BR T.
    6/ keep your old pots handy. Figure out the best way to get them in and out. Once I figured out that key, getting everything inside was easy enough. For me it was stem first with lugs facing the centre of the guitar, snug against the corner point of the f- hole. It was so snug I am almost convinced the f-hole dimension was influenced by the CTS pot dimensions.
    7/ try out your wiring before you insert it all. Test your pu is attached to the pots you expect, use a continuity tester (on any multimeter) to test earth from cable shield through pots and PUs through to bridge. Once strung up again you should be able to see common earth from low e tuning peg all the way to the plug shield at your amp end.

    All up relax, try to enjoy the journey, get everything ready first tool wise and take your time. Someone got it in there the first time. I can see how epiphone cut corners when they did it in factory (fly leads soldered in situ ) but it is possible. Use a soldering iron >15w if you can get access to one. I picked one up a while back at a local electrical supplier pretty cheap. Don’t need the full soldering station.

    for those who want to nerd out on the gear-
    pickups are Mick Brierly Jackdaw low wind PAFs. Beautiful craftsmanship, quality and service. Made to personalised spec. Comparative bargain.
    wiring harness came from ‘guitar sauce’ and is a 50’s wiring, Orange drop caps and again a work of art. Stellar service and presented so well.
    In light of Covid lockdowns and the impact to our small businesses worldwide I chose to think global and support local.
    In your neck of the woods no doubt you can do the same. It was good to know that in Aust there are at least two guys who are the real deal on a world stage and I can’t plug them hard enough for their fine work.
    cheers all.
    PM if you want any detailed answers to anything.
    EMike

    ps I probably need to say this at some stage- the guitar is transformed. The wiring harness has more functionality and rage of adjustment. The clarity, chime note separation of the Pickups is a revelation. There is no high wind compression that the previous stock came with I can see below 8.5; The pickups were specked to enhance the woody hollowness of the semi. This Epiphone 339 is whole next level without the price tag that typically assumes. Love it. So does my Son who’s guitar this is for in the first place.
    emike

  5. #4

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    If you had to scrape CA glue off, you used about a hundred times too much. A bare drop is more than enough for the job, really less than a drop. For placing pots into mounting holes, something like the StewMac archtop helper is the best tool. I make mine from wire coat hangers. They work like a charm through the f holes. The entire harness should be inserted through a pickup hole, not the f holes, although the latter can work, it's just harder. To get the output jack into place, I use a regular 1/4" plug, with all the extraneous material cut away so it goes through the mounting hole with a short cable connected, into the guitar far enough to get to an f hole, where I pull the jack and plug out enough to be able to put the plug into the jack, and take it back out through the mounting hole. Do the job a few dozen times, and you learn some things that work, and some things that don't quite make the cut.

  6. #5

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    Good points/

    the guitar was a semihollow/ pickups are in a routed cavity- no access to the lower bouts save for a small hole for the leads. But yep if I had the choice- I would have taken the path of least resistance.

    regarding the cca though- as a glue it was quite runny and tracked/wicked through the threads. And this was just a drop. Getting it out of the threads so I could turn the locknuts without seizing is what took me the time.

    good idea for the jack- I skinned the cat a different way and used what I had at hand: some of the wire I took out. I threaded it in the hole, then through the jack. Tied a thumb knot to block up in the hole when you pull the jack out the hole.
    cheers
    mike

  7. #6

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    A used guitar string works well enough. The end that was in the tuner capstan holds the jack firmly enough to pull it through the mounting hole, and then a harder pull will bring it all the way out. If you cut the strings when you change them, this won't work, of course. I usually keep at least one set of used strings on hand, mostly in case I need to use them for this, but I haven't needed to since I made up the plug. For only occasional use, a used guitar string works well enough.

    I also work through the f holes on some guitars. I have a couple of acoustic archtops with floating pickups, which have thumbwheel controls mounted in the treble side f hole. Those are small enough to be no trouble to get through the hole, and the wiring is long enough to allow safe soldering outside. Different tricks for different instruments.