Wiring issue

Tone_Chaser

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Chasing a wiring issue on the Les Paul copy I built. The bridge pickup doesn't work most of the time and with both volumes down, there is still signal coming out. There is more volume with the POTS up, but still plenty of signal.

I checked it with a meter and at first the bridge pickup read a little over 8K and the neck pickup was about 12 ohms. I un-soldered it and it read just under 8K. So I reattached it and it read okay but the bridge pickup dropped to around 12 ohms. Did the same and it seemed to work okay. I had good signal from both pickups. I forgot to check if the volumes worked.

Took it to practice the next night and it did it again. Nothing from the bridge and the volume didn't kill the signal.

I'm about to rip everything out and start over. There has to be something shorted somewhere, that's the only thing I can come up with anyway. I don't think a bad switch would do that because it's after the volumes.

Looking for thoughts from any gurus out there.
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ARandall

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The braided connections need looking at for one. They are almost guaranteed to be cold.
Many of your pot casing joints also look a little 'chilly'. You need a hot iron for that.....so it's only a few seconds of application before the solder melts.
Might be worth re flowing most of the lug connections too just to be sure.
 

DaveR

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I agree that the joints look like they might be cold. I always had a hell of a time getting grounds to solder to the back of a pot with my fairly small iron, because all that metal acts like a giant heat sink and takes forever to get hot in one localized spot. I also ruined a really nice pot once by getting it too hot. For transferring more heat on guitar wiring I try to use a chisel tip in my iron.

I have found that soldering directly to a pot casing I have much better luck if I slightly scuff up the pot casing with sandpaper first and pre-tin a puddle on there. Then I can lay my wires onto the hardened puddle, pin them down with a tool in one hand and reflow the whole puddle with my iron in the other hand.

Try reflowing everything and let us know what happens!
 

ehb

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Liquid flux makes it simple. Keller brush top bottle.
 

Tone_Chaser

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I've done quite a few pickup installs before but they've all been modern 4 wire types. This is the first time I tried the vintage type and was nervous about ruining the POTS.

I upped the heat and went for it. They look better now but it didn't solve the problem. I ended up pulling the caps and the wires from the lugs, tested everything and started over. I wired the bridge pickup without the tone POT and it worked fine. Next, I moved to the neck pickup and there is the problem. With the POT on 0 there is still about 80% of the volume coming out of the guitar.

I did some more research toning and found the problem is likely a bad ground on the third lug. I looked at the solder joint and it didn't look good, so I soldered it again and got a strange result. On 0 I still got the sound but it shuts off a 1 and starts fading in at 3 and at 7 it jumped up and there was no change from there to 10. I've done it several times and can't get it to work so I think I'll replace that POT and hopefully that will solve it.

Thanks for the help!
 

ARandall

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The lower your iron is set the more likely you are to kill the pots. High heat means the local area has a lot of temperature before the heat can move off and heat up the more delicate internals.
 

cmjohnson

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Use enough heat. Get a bigger (higher wattage rating) iron. A soldering iron is an INVESTMENT, not an expense, so hit your piggy bank with a hammer and spend the money on a good iron.

And, do yourself a big favor and buy a genuine brand name iron from a reputable source, and NOT a chinese knockoff of the same item. The quality difference can be astonishing.

I recommend Hakko and JBC irons. They can be pricey but I've never once regretted dumping 250 bucks on a Hakko FX-951. It is very nearly the god of all soldering irons, Get an assortment of tips including a big fat chisel tip for making ground connections.
 

ehb

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Temp is indirectly proportional to Time-to-Solder.

Higher temp, you've got be quicker.... Joint has to be cleaner (time again, oxi and kank decreases heat xfer a LOT, again time)

Flux cuts time.
 


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