60th Ann MIM JM - Wiring question with pictures

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NateD81
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60th Ann MIM JM - Wiring question with pictures

Post by NateD81 » Fri Jan 04, 2019 7:13 pm

Hello!

I bought a 60th Ann. MIM JM a couple months ago and love it. My only complaint is a pretty irritating electrical buzz whenever one or both hands leave the guitar. Sometimes I get a slight popping sound when I touch the bridge or the pickups -- something that happened to me on an old tele that I swapped out the bridge on (the problem with that guitar is that I didn't do a good enough job attaching the ground wire to the bridge). I suspect I'm having a ground issue so I opened up the guitar this afternoon and here is what I found...Is this typical or in any way unusual?

Image

and the cavities:
Image

My limited understanding/research has led me to believe that the black paint should be touching each cavity to create continuity, but as you can see, that definitely is not happening. Also, note the bird's nest of wires. This is a brand new guitar so that is how it came from the factory.

I've never used copper adhesive tape to shield a guitar but ordered some and watched some tutorials on how to do it, do you guys think that might solve my buzzing issue? I've moved the amp to different rooms, simplified the setup to just guitar + amp and tried different cables to determine the issue is not something else. I figure I might as well do the shielding at this point - but again - it seems like the issue could be the (what looks like to me) shoddy shielding paint job in the cavities. Anyone who knows more than me (which qualifies just about everyone) care to chime in?

Lastly - should I shield the entire pickguard as well? Not sure if what is already there is sufficient. I just figured that if it's worth doing, I ought to do this right so I don't have to do it again down the road.

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timtam
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Re: 60th Ann MIM JM - Wiring question with pictures

Post by timtam » Fri Jan 04, 2019 9:30 pm

Yeah that's a pretty poor paint schielding job by Fender. Worth doing the copper foil thing if the guitar is noisy, although a huge improvement can't be guaranteed. But sometimes it is. Use double side copper tape, ie conductive adhesive so that the shield is electrically continuous when overlapped. Otherwise you need to do something like a solder blob on the edges to make it electrically continuous. Do the (rest of) the pickguard as well. And make sure that the cavity shielding is grounded; either by wire, or just having it over the top edge of the cavity walls so that it contacts the pickguard shielding is enough to do that. The pickguard shielding will already be grounded by contact with the rim of the output jack (and any grounded pots). If you have a multimeter you can verify that everything is continuous and grounded.
"I just knew I wanted to make a sound that was the complete opposite of a Les Paul, and that’s pretty much a Jaguar." Rowland S. Howard.

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NateD81
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Re: 60th Ann MIM JM - Wiring question with pictures

Post by NateD81 » Sat Jan 05, 2019 7:58 am

timtam wrote:
Fri Jan 04, 2019 9:30 pm
Yeah that's a pretty poor paint schielding job by Fender. Worth doing the copper foil thing if the guitar is noisy, although a huge improvement can't be guaranteed. But sometimes it is. Use double side copper tape, ie conductive adhesive so that the shield is electrically continuous when overlapped. Otherwise you need to do something like a solder blob on the edges to make it electrically continuous. Do the (rest of) the pickguard as well. And make sure that the cavity shielding is grounded; either by wire, or just having it over the top edge of the cavity walls so that it contacts the pickguard shielding is enough to do that. The pickguard shielding will already be grounded by contact with the rim of the output jack (and any grounded pots). If you have a multimeter you can verify that everything is continuous and grounded.
I was considering purchasing the shielding paint and just finishing the job properly, do you think that could help? The thing that seems so strange is that the guitar is quiet when one hand is on the strings and the other is on the bridge, but if it's just one hand on the strings, it's still buzzing. When the second hand touches the bridge, right before it gets quiet, there is a slight popping sound. Again, I'm no expert, but it seems like something isn't properly grounded? I guess I could try the paint AND the tape, although my fear is that I'll start chasing ghosts.

Edit: I checked continuity and I have continuity from the rhythm switch bout to the neck pickup, but no continuity from the neck pickup to any other part of the guitar (bridge pickup and the lower bout) — I suspect this is the issue and the cavities need to be linked together?

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Re: 60th Ann MIM JM - Wiring question with pictures

Post by timtam » Sat Jan 05, 2019 5:42 pm

Some confusing aspects of conductive paint performance discussed elsewhere today ...
http://www.offsetguitars.com/forums/vie ... 3#p1538691

With paint, I always run a ground wire from main ground to each cavity. But given that the paint job is poor I would go with the copper tape. With that you should get complete continuity just by virtue of tape over the cavity rim touching grounded pickguard tape (grounded by contact with the output jack rim / grounded pots). But you can run ground wires to the cavity foil too if you want (looks like you may already have them ?).

Re current buzzes, do you have continuity between the bridge and output jack rim ? Trem and jack ? Strings and jack ? If one ... then you should have all three (unless you have non conductive saddles).
"I just knew I wanted to make a sound that was the complete opposite of a Les Paul, and that’s pretty much a Jaguar." Rowland S. Howard.

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Re: 60th Ann MIM JM - Wiring question with pictures

Post by NateD81 » Sat Jan 12, 2019 3:39 pm

timtam wrote:
Sat Jan 05, 2019 5:42 pm
Some confusing aspects of conductive paint performance discussed elsewhere today ...
http://www.offsetguitars.com/forums/vie ... 3#p1538691

With paint, I always run a ground wire from main ground to each cavity. But given that the paint job is poor I would go with the copper tape. With that you should get complete continuity just by virtue of tape over the cavity rim touching grounded pickguard tape (grounded by contact with the output jack rim / grounded pots). But you can run ground wires to the cavity foil too if you want (looks like you may already have them ?).

Re current buzzes, do you have continuity between the bridge and output jack rim ? Trem and jack ? Strings and jack ? If one ... then you should have all three (unless you have non conductive saddles).
So after checking everything you recommended I decided to try getting some copper tape and shield the whole guitar. Buzzes are gone, but I was still getting strange clicking and popping sounds when I touched metal, despite continuity EVERYwhere! When I was turning my amp off I noticed the power strip did not have a ‘ground’ light illuminated. It then dawned on me to check to see how I had the power strip plugged in because it had been awhile since setting up my garage. Genius that I am, I plugged the strip into an extension cable using a three-to-two prong adapter (more genius), hence the power strip not being grounded. Once I plugged the power strip in properly and got the ground light illuminated - tada! Guitar is quiet as a mouse, no weird clicks or pops.

I sure learned a lot and learned to check some simple things first...at least the guitar is properly shielded! :fp:

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