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Bridge PU doesn't work with cover on

michaelb

New member
Joined
Jul 29, 2018
Messages
21
I have changed out magnets many times without a problem. I recently removed the cover of the bridge PU, carefully using a dremel wheel, and removed the magnet and replaced it with another magnet. Now I usually place a small piece of painters tape between the screws and lugs and apply 4-5 small dabs of silicone then replace the cover and re-solder the sides. When I did this it suddenly resulted in no volume. When I placed the selector switch in the middle position there was no bridge volume but I could hear a tonal change with bridge tone knob. Here is the thing, when I removed the cover it works fine but when I put the cover on the bridge PU there is no volume. I checked connections and sprayed contact cleaner with no improvement. Something with the cover is causing the problem. Any suggestions?
 

Zentar

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Joined
Oct 1, 2011
Messages
830
You will need three hands to do this but can you measure the PU resistance as you put the cover on and see if it suddenly shorts to open or around 5meg both of which indicate the cover is touching the coils somewhere.
Your resistance should be around 7ko-12ko normally depending on what kind of PU you use.

Shorts also occur when you put the back cover back on. Wires get pressed down
 

michaelb

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Jul 29, 2018
Messages
21
Zentar: I will try that. I have a 57 Classic (+) in the bridge and it is usually around 8. I think I tried that using my cable to measure the PU resistance. When I measured it without the cover it was 8.1 and with the cover 0. But I will try again. I'll try looking around with a magnifying glass for problems. I will get back with the results.
 

jwalker

Les Paul Forum Sponsor
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Dec 10, 2004
Messages
2,592
My guess is you have one of the soldered connections that is poking through the tape and grounding out on the cover. Or you may have the magnet sitting on one of the leads and when the covers goes on it pushes hard enough on the lead to cut through the insulation and the pickup grounds out on the baseplate. Check for both of those.
 

michaelb

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Joined
Jul 29, 2018
Messages
21
Ok the bridge PU measured 8.32 with the cover off; with the cover pushed on 0.01. Now when I barely backed off the cover just slightly above the screws it worked fine. I carefullly removed the magnet and carefully slid another in with same results. I actually did one wrap of tape around PU with same results. Jonseyblues thought I may have damaged the PU inserting a new magnet, may have nicked a coil wire or the series link wires connecting the coils could be loose. Pushing the cover completely down does something.
 
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Michaellen

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Joined
Jul 16, 2018
Messages
1
Bridge PU doesnt work with cover on

Thanks for the correction Allanswood & Rod, I misread that. Does anyone know what the Millenium cover went for & have a scan of it? Brad
 

chasenblues

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Jul 3, 2006
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1,228
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rick c

Active member
Joined
May 28, 2016
Messages
282
It does sound like a single broken wire to me. I had a neck pickup that would work perfectly when I pushed it down toward the neck but shut down completely when I let it loose. One little wire will cause this problem and it may be difficult to troubleshoot. I bought a replacement pup and one wintery day when I have nothing better to do, I will pull the old one apart and see if I can find where the broke wire is and fix it. It's highly likely to be an outer winding so if you can find the break, just remove the section after the break and resolder the good end back to the appropriate pup main wire.

Good luck
 
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michaelb

New member
Joined
Jul 29, 2018
Messages
21
Rick c that makes sense. That's my plan, to by a new PU (s), and is the cost of experimentation. But, I did learn a lot just the hard way. I'm eyeballing Wolfetone Dr.V or Legends. Its all about the $$$$$. Well, my soldering skills are getting a lot better. For sure, I will be taking this PU apart eventually. I just have to find out.
 
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