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Soldering wires to pots and lugs: the mechanics of it?

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by Snakum, Oct 21, 2004.

  1. Snakum

    Snakum Member

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    Location:
    Fayetteville, NC
    From the mechanical dummy files ...

    I need to place a capacitor from the middle lug of my FrankenStrat's volume control to the outer, non-grounded lug. Both terminals already have a wire in them, of course. The outer lug is wired to the switch and the middle lug has a wire going to the input jack (along with a ground wire). I am concerned that I don't 'unsolder' the existing wires, so it seems to me, I would merely heat the leads of the capacitor and stick them into the existing solder and thru the holes, beside the existing wires. Is this correct?

    I also need to place a cap on my neck pickup tone control, and one capacitor lead will attach to an unused terminal (the out lug) and the other will ground to the top of the pot, going by how the other tone control cap is placed. When I place the lead to the bottom of the pot (ground it?) ... do I tin the lead, then heat the pot and touch the tinned lead to it, or should I use some other method?

    Thanks for any help at all. I am totally clueless about this stuff and with a soldering gun I am an accident waiting for a place to happen.

    Minh
     
  2. saros141

    saros141 Guest

    In the first case, I'd say it would be better to heat the joint, and then when it liquefies, poke the cap lead through. Don't worry too much about disrupting the original connection, it should be fine. I doubt it's possible to heat up the cap's lead enough so that melts the solder on its own.

    Soldering to the back of a pot is trickier. You want your iron to be good and hot for this, then you want the lead to be held tightly against the pot. I use a little pair of needlenose locking visegrips for this, it frees up both hands and heatsinks the cap a bit so the excessive heat is less likely to damage it. Hold the tip of the iron firmly to the pot casing, up against where the lead is secured. Once it heats up, poke a length of solder into the place where lead, iron tip, and casing meet. The solder should flow into and around the connection. Remove the iron and don't move anything while it cools.
     
  3. Snakum

    Snakum Member

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    Thanks very much, I appreciate the info.

    Minh
     
  4. alderbody

    alderbody Member

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    i believe it could be better if you got your axe to a tech and asked him to do it for you.
    An unexperienced hand with a soldering iron could become a disaster for guitar electronics, which would result in crappy tone or worse in need for replacement of stuff...

    If not a tech, then a friend with more experience in soldering under your guidance...

    It's really not a difficult thing to do, but what scares me most is that you'll have to heat the pot's body in order to solder the cap.

    Careful with that cause you might burn the resistive surface if you overheat it, or if there are any plastic parts inside they might melt and disfigure...


    anyway, good luck man! :)
     
  5. Snakum

    Snakum Member

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    I got everything in OK last night, and it wasn't too bad once I got the hang of it. It's not pretty, but it works. The cap across the volume pot works great, and I'm not losing anywhere near the treble I was losing. No problem. However ...

    When I put a cap on the neck tone control, I just cut the wire running from the middle tone pot (which had the sole capaciter) to the neck tone pot, then soldered a cap from the #1 lug (where the wire from the middle tone pot was going) to the top of the potentiometer. It wasn't that hard. But when I put the guitar back together I found that the number 2, 3, and 4 positions all buzz BADLY. The number 1 and 5 positions are fine, but anything hitting the middle pickup gets a very high-pitched hum.

    Any ideas?

    Minh

    BTW ... the pots are 500K, and the cap I used was a .022uF Ceramic (they didn't have film caps that size).
     
  6. alderbody

    alderbody Member

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    search for any short-circuits somewhere near the mid p\u connections.

    seems like your mid's hot wire touches an earth point somewhere.

    you can get a schematic of your guitar's wiring and double-check the connections.

    a place to find some is fender's Mr. gearhead (www.mrgearhead.net) or guitarnuts.com where you can find many cool alternative wiring schematics.

    always doudle check before you reassemble the pickguard

    i'm sure you'll get it right! ;)
     
  7. Jim Collins

    Jim Collins Member

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    500K pots, with single coils? No wonder you are losing so much treble when you back off on the volume. A better choice for single coils is 250K pots. The treble loss is not nearly as great. Even if you have a bridge humbucker, 250K pots are a better choice, since most of your switching combinations will be either a single coil, or two coils in parallel. You'd probably find that, with 250K pots, you wouldn't need the treble bypass cap.
     

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