DIY Replacing LP Pots, Switch using pre-wired kits?

fred4321

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Hi,
I just had a grounding issue on my Greco LP sorted by a technician. He suggested that I look at replacing the pots and PuP switch, in his words 'its a real mess and old' and will improve the tone overall of the guitar due to a residual hum from the electronics - he added that the PuP's are fine.

I have seen some pre-wired harness kits on the web (don't know much about them -quality, what to look for etc) and solderless LP kits.
I as a DIY project I'm wondering if an amateur like me can do the job myself. Would a solderless kit be easier ect?
 
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SixStringSlinger

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You can absolutely do it yourself so long as you know how to solder (and if you don't, you can learn enough to wire up a guitar quick) and follow a wiring diagram.

I'm not sure how Greco dimensions compare to "real" LP's, but if there's any discrepancy then DIY may be the best bet for you anyway.

I'm not sure what sort of hum would be cured by new pots, caps and switches that won't be cured by proper shielding, grounding and making sure all connections are solid. But if you're interested in learning soldering (assuming you don't already have those skills down), you'll learn a lot of the same ones checking these things as you would re-wiring from scratch.

My LP's wiring was fine, but I re-did it all from scratch partially just because and partially to make sure all my pots were slightly above spec to make sure I can get things bright if I want to.
 

Freeman Keller

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Hi,
I just had a grounding issue on my Greco LP sorted by a technician. He suggested that I look at replacing the pots and PuP switch, in his words 'its a real mess and old' and will improve the tone overall of the guitar due to a residual hum from the electronics - he added that the PuP's are fine.

I have seen some pre-wired harness kits on the web (don't know much about them -quality, what to look for etc) and solderless LP kits.
I as a DIY project I'm wondering if an amateur like me can do the job myself. Would a solderless kit be easier ect?

Rewiring your lester will not "improve the tone overall". If you change the tone capacitor VALUES you can affect where and how much the tone pot rolls off the highs. I have no idea what a "residual hum from the electronics" means - you eliminate hum by good wiring practices including shielded wire, common ground point, a string ground. Cold solder joints at your ground points (backs of pots) are a potential source of noise.

Soldering is not rocket science but it is definitely a skill (ironically my son is a journeyman electrician yet he has me do all his soldering). Buy a 25 watt soldering iron, some rosin core electronics solder and some bits of wire and practice until every one of your solder joints is bright and tight. You need to learn to get the components hot enough and then feed the solder in so it flows into the joint.

Wiring a les paul is a bit tricky - the cavities are deep and there isn't much room inside. I like to make a little jig with exactly the hole spacing that I have on the guitar, then do the interconnection between the four pots. Put that in place and fish the cable to the switch and the pickups. Use a shielded cable to the switch, the pups will be shielded. You pretty much have to do that in the cavities.

IMG_2120.JPG


IMG_2122.JPG


One thing to consider if you are rewiring is to make this simple little change

1642727208393.png


It makes it so with the switch in the middle position turning one volume all the way down doesn't kill both pups.

Good luck, take your time and do good work.
 

Freeman Keller

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Its ugly and not very good worksmanship but I really don't see significant problems. It looks like the wire from the switch to jack is shielded, that is good. Pickup leads are also shielded as they should be. It looks like the wires from the volume pots to the switch are not - that is one thing I would change. I am guessing that the black wire might be the string ground to the bridge - you definitely want that - pull the bridge pup and make sure a wire goes back to the bridge stud.

If you have scratchy pots that you want to replace this would be a good time to do it, but otherwise I would say its functional but not pretty.
 

Freeman Keller

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I'll add that if you want to rewire yours and learn how, buy a kit like the StewMac one


Disconnect the leads from the pickups and to the switch and the black ground wire. Remove the complete assembly from the guitar and set is aside. Either duplicate the wiring or make the modification in my first post, but basically make a completely new assembly. If the wires to the switch are not shielded replace them with wire from the SM kit (it should be). Connect the pups and switch leads and all the grounds. You should be good to go.
 

moosie

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I usually say this to new AMP solderers, but since access is difficult on these guitars...

Solder each joint as if your life depended on it. One at a time, making sure it's perfect before moving on. Doing a bunch, "probably good, I'll sort any issues later" is a recipe for difficult troubleshooting.

Have fun!
 

Telekarster

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I'll 2nd what Freeman and SSS is sayin' - Build it yourself. Don't buy premade cause it may not fit. Make a template, get the proper parts, solder away ;) I just did my 56 goldtop about a year ago, never did it before, and it really wasn't that big a deal. Just take your time and be darn careful with the soldering iron cause it is VERY HOT! Always know where it is, what its close to, and if it's on or off... always. Good luck man!
 

fred4321

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Cool, now I have to think of which parts to get. I want to change everything including the switch and lead plug (not the PuPs- haven't decided what ones to replace them with-if I wanted do that).
I read somewhere a 50's wiring is a good idea. I know these are metric measurements for the Greco and believe they are short shaft pots.
Can I get some advice on the parts I need to get?
 

Freeman Keller

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Can I get some advice on the parts I need to get?

That StewMac wiring kit that I linked has every thing you could want. You can also buy the parts piecemeal but the kit makes it easier. Every Lester that I've worked on takes long shaft pots but it would be simple to pull yours out and measure. Everyone has their favorite capacitor (and you can spend a bunch of money for boutique bumblebees) but there is no functional difference. CTS and Alpha pots are both good. If you get solid shaft pots you can only use set screw knobs. Switchcraft switches and jacks are industry standard.
 

fred4321

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Hi, almost ready to go. Just a question ...
I checked out the pot spindles on the top of the guitar and they all seem to be different (brand type?) and there is damage around the surface near the spindles, so my guess is they had been drilled out to accommodate the imperial size pots.

1. Would I need to replace all the wiring?

cheers
 

Freeman Keller

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I've always used CTS pots and I'm pretty sure they take a 3/8 hole and have a 3/8x32 thread. Just looking at the specs at StewMac, it looks like Alpha takes a 5/16 hole and has a M8x0.75 thread. Others might be something else. Its easy for me when I'm building a new guitar, I just drill the right size hole for the pot I'm going to use. You should measure yours and look for something similar.

There are at least two different shaft lengths, most wood topped guitars take long but measure yours. There are two different kinds of shaft ends - split/knurled which takes push on knobs and solid which takes set screws. Again, look at yours unless you want to change the knobs


There are other manufacturers of pots - I use long shaft CTS on my LP clones with push on knobs and short solid shaft for my tele clones.
 




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