replacing wiring on a semi hollow guitar

Discussion in 'Other Guitars' started by Col Mustard, Feb 17, 2016.

  1. Col Mustard

    Col Mustard Well-Known Member

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    So I know you've all been just dying to know the secret of how to
    get a new wiring harness into a semi hollow body guitar.

    It's fiddly and time consuming, but it doesn't have to be traumatic.
    Here are tips I got from the irreplaceable Dan Earlewine:

    Draw a template of the holes on your guitar, so you can build the new
    wiring harness to fit.

    Tie strings to each of the old components before you remove them from
    the instrument. I used 10# test fishing line for this project. old Guitar strings
    will also work. leave the strings between two and three feet long (.6 to 1 meter).
    I used slip knots to go around each component's neck.
    _DSC0029@100.jpg
    pull the old wiring harness out through the F-hole. try not to nick your trim or
    paint on the edges of the F-hole. This is why they paint these edges black, as well
    as to hide the plywood layers on my epi.

    _DSC0028@100.jpg
     
  2. JohnnyGoo

    JohnnyGoo Well-Known Member

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    very imformative,thanks for posting.
     
  3. Col Mustard

    Col Mustard Well-Known Member

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    I bought this Epiphone ES-339 P-90 pro about nine or ten months ago.
    I've done some mods to it, but had not delved into the innards until now.

    Funny, most guys rip the p'ups out first, even on a guitar they've spent lots of
    money to acquire. I didn't do that, partly because the I thought the Epi sounded
    good stock, and partly because I wanted to play it for a good long time
    and get to know it as issued, and partly because I wanted to see if the Epiphany
    hardware would live up to its reputation for un-dependability and being
    cheap junk.
    _DSC0030@100.jpg
    CTS 500k pots eh? this is what I pulled out of the cavity.
    This guitar was a total impulse buy, although I'd been drooling over the Gibson version
    for a long time
     
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  4. javamagic

    javamagic Well-Known Member

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    Those CTS pots must have been a squeeze through the f-hole. If the components are too large you may have to feed them in through the pickup holes instead.
     
  5. 67plexi

    67plexi Well-Known Member

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    Most USA made hollow body guitars you run the wiring through the neck pickup cavity.
    The most fun is a three pickup Gretsch. Not. All my Gibson Custom Shop guitars have JM Rolph pickups in them with 1950'S Sprague bumble bee
    capacitors. Huge difference the stock burstbuckers sound like mud.
     
  6. Col Mustard

    Col Mustard Well-Known Member

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    This ES-339 is a semi-hollow body... which means that it's got a center block.
    And P-90s. So nothing gets in or out of the pickup hole. The harness has to go back
    in through the F-hole. Easy does it. Hence the fishing line strings to pull each
    component into its proper place.

    I think when they build these guitars, they install the wiring harness before they glue
    the back on. So it would be nice if they used good quality parts that didn't need to be
    replaced. That was my fond hope when I bought this instrument.

    Where'd they get those CTS 500k pots, we wonders, yes we wonders.

    Does it stand for Chinese Telephone Supply? Has CTS now built a factory in China, staffed by elementary school age truants and their exploited mamas, criminal laborers and aging POWs?
    This guitar was a total impulse buy, although I'd been drooling over the Gibson version for a long time. I played it a lot for the last eight months or so, and
    then the selector switch began to fail. There it is. Time to start replacing parts.

    So I haven't bought new pickups, but I have a wiring harness that I assembled for my '07 SG special. Way back in 2008, the prevailing wisdom on this site was
    that Gibson components are crap and should be replaced immediately.

    I was only a newbie... what did I know? I read all these posts and thought,
    "Man, I want the BEST for my favorite (only) Gibson." I wanted to learn how to do it anyway. So I bought some good quality Alpha pots and Switchcraft jack and selector, wired them together, pulled the Gibson harness out in one piece
    and installed my creation. It worked fine. I replaced Gibson's 300k pots with
    the Alpha 500k pots and the tone improved in some subtle ways. That was
    my perception anyway.
    _DSC0034@100.jpg
    Later on, I popped for a lovely "premium' wiring harness from Martin SixString
    and removed my hand built set in favor of this more professional rig. And it works fine and my SG sounds so good it vibrates my soul.

    Having some trouble uploading pictures... I'll try again later.
    The site seems flakey and jumpy, or else it's paralyzed. or maybe it's my computer.
    Anyway, there's a photo of what I'm installing, above. Since it's already assembled,
    all I have to do is solder the leads from the pickups to the volume pots, and the
    ground wire to the ground.
     
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  7. 67plexi

    67plexi Well-Known Member

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    I hate Alpha pots in amps or guitars. As far as the construction of your guitar that block stopping the wiring harness is just wrong or in China Wong.
    The more I learn the less I know. PEC pots are good but still 15 degree taper and if you have to fish through the F holes they wouldn't fit.
     
  8. 67plexi

    67plexi Well-Known Member

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    I hate Alpha pots in amps or guitars. As far as the construction of your guitar that block stopping the wiring harness is just wrong or in China Wong.
    The more I learn the less I know. PEC pots are good but still 15 degree taper and if you have to fish through the F holes they wouldn't fit.
     
  9. Col Mustard

    Col Mustard Well-Known Member

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    well, I just sent away for a kit of 'better' parts, because I like this Epi so well...
    AND because I got the above harness soldered to the pickups, and tested it before
    trying to cram it in the hole... and it didn't work. Duh...

    so, begin again. more photos when this site stops acting flakey.
     
  10. Col Mustard

    Col Mustard Well-Known Member

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    trying to edit my post and my changes disappeared.
    I don't know what's more frustrating, working on guitar parts that don't work
    or trying to use this forum.
     
  11. WallaceWinston

    WallaceWinston Active Member

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    Very interesting read, thanks for posting. I'm having alot of trouble with the site too colonel.
     
  12. ScottMarlowe

    ScottMarlowe Well-Known Member

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    Actually I think it's the internet. A LOT of sites have been having issues this week.
     
  13. PermissionToLand

    PermissionToLand Well-Known Member

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    CTS pots aren't that much more expensive and Epi has some huge economies of scale so I'd bet they're real.

    Working on semi-hollows is a real PITA, even with the string method. I'd friggin' drill into the back and make an access panel if I had the skills.
     
    Last edited: Feb 23, 2016
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  14. lineboat

    lineboat Well-Known Member

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    So that thing had CTS branded pots in it? Wow. And 500k? WOW.... No wonder you thought it sounded so good..... Have you checked them with a meter, just for giggles, just to see how close to right they are? I'm still impressed with the beauty of that one Col. Simple yet stands out.
     
  15. Col Mustard

    Col Mustard Well-Known Member

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    I haven't tested the stock pots, maybe I will when I get this project going again.
    I got real sick over the weekend and am slowly recovering. I decided that I like this guitar so well
    that I'm upgrading everything. I ordered a couple new P-90s from Rose, and am waiting on them
    to arrive as well as my new high class harness.

    And yeah, my general opinion of this Epi is that it's amazingly good, especially considering how little I paid for
    it. I was happy with the P-90 sound from the stock components, and the only reason I dug into it at all was that
    crackle in the selector switch. Once I got in there, I reconsidered just about everything, and figured:
    "Might as well get the best."
     
  16. Col Mustard

    Col Mustard Well-Known Member

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    Got that right... I actually seriously considered it cutting my own trap door in the back. I have an extra back plate from an SG, and it wouldn't even
    look out of place IMHO. The reason I hesitate to cut out a hole in the back is that when Polyurethane chips, it chips BIG... so I'd likely end up with a
    raggedy looking eyesore that I didn't intend. ~( :^O#
     
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  17. ScottMarlowe

    ScottMarlowe Well-Known Member

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    My experience with poly is that you need 2 or 3 tight layers of painters tape in place if you're gonna drill or cut through it. That's from replacing tuners on a few epis.
     
  18. lineboat

    lineboat Well-Known Member

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    ^^^ That helps, and you can also "score" the poly layer with a razor knife prior to cutting the wood. And make sure to stay inside the lines!
     
  19. smitty_p

    smitty_p Well-Known Member

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    Interesting thread, Colonel.

    Here's a thread where I did essentially the same thing. I used clear aquarium tubing, though, instead of strings.

    Did you use full-size pots? It looks to me like they may be.

    I used Bourns mini-pots in mine and found they went through the F-holes pretty easily.

    At any rate, nice work!

    http://www.everythingsg.com/threads/rewired-new-pots-and-caps.18805/
     
    Last edited: Feb 25, 2016
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  20. PermissionToLand

    PermissionToLand Well-Known Member

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    True. Also, how would you create the recessed area that the cover is screwed into? I don't understand why they don't just do it from the factory, I mean who looks at the back of the guitar anyway? And the effect on tone is surely negligible.
     

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