Help -- I connected my new pickups, but ...

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Tsunami Tom
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Help -- I connected my new pickups, but ...

Postby Tsunami Tom » Wed Dec 28, 2011 12:11 pm

Hello everybody and thanks for any help you can provide. I bought some new Mosrite-style pickups for my MIJ Mosrite. I'm not very savvy when it comes to electronics and I don't have a multi-tester. When I received the new pickups and looked at the wiring, the MIJ wiring didn't seem to match the pictures of Mosrite pickup wiring that I had seen. So, I decided to attempt to wire the pickups to match the various pictures that I had collected over the years of vintage Mosrite wiring. Unfortunately, the pics that I have are all a bit murky in places, but I did my best. I had bought two new 500K audio taper pots, but the shafts were the wrong size. So, I kept the original pots and only replaced the capacitor with a .05 cap that I bought.

Anyway, when I first wired the new pickups, they sounded very dull with not a lot of twang. The volume and tone controls worked OK, though. I was surprised at the dull tone and I immediately suspected that it might have something to do with my wiring attempt. After studying the various pictures some more, I realized that I had connected the one end of the capacitor to ground on the tone pot, and then bridged over to the one end point on the volume pot; however, in some, but not all, of the pictures, the one end of the capacitor is grounded on the tone pot and then is bridged across the end points of both pots.

So, I did that and the pickups sounded much better with the twang that I had expected. Unfortunately, now, as soon as I back off the volume pot, the volume cuts out. The guitar sounds great if the volume pot is all the way on, but, as soon as I back it off even a smidgen, the volume is cut off altogether.

So, I took two pictures of the wiring as it is. I'm hoping that you can give me a suggestion. As you can see from the two pictures (you'll have to connect to them), basically, the positive line from the switch is bridged across two of the end points on each pot. The negative line from the switch is grounded on the volume pot. Then, one end of the capacitor goes to the middle point of the tone pot, and the other end of the capacitor is grounded on the tone pot and then bridged across the other two end points on each pot and continues on to ground on the volume pot.

Here are the two pics:

http://www.oberlin.edu/staff/thinders/w ... CF3604.JPG

http://www.oberlin.edu/staff/thinders/w ... CF3612.JPG

Thanks again very much for any help!
Tom

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Re: Help -- I connected my new pickups, but ...

Postby dubtrub » Wed Dec 28, 2011 12:26 pm

I'm on my way out right now but will take a look when I return this afternoon. Meantime I'll post a couple of pix to review. Maybe someone else will jump in an help.

Image
Image
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Re: Help -- I connected my new pickups, but ...

Postby oipunkguy » Wed Dec 28, 2011 1:41 pm

http://www.seymourduncan.com/support/wi ... h_1v_1t_3w

this is the closest wiring diagram I could find to a mosrite setup. it's just using humbuckers instead of single coils. in the diagram ignore the red and white wires coming from the pickups that are soldered together. on a mosrite pickup the white wire is the hot, and in this diagram the black is the hot. mosrite ground from the pickup is black, and in this diagram is the green and bare wire soldered together. if you have just one wire coming each pickup with an inner core (two conductor wiring) the inner core is your hot and the outter is your ground always. if you need any extra help feel free to PM me and I can walk you through it. good luck.
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Re: Help -- I connected my new pickups, but ...

Postby Tsunami Tom » Wed Dec 28, 2011 2:05 pm

Danny and Aaron,

Thanks for taking the time to reply. I appreciate it. I'll use these pics to re-evaluate my wiring attempt. They give me a better understanding of how the wiring is supposed to be.

I'll let you know how it goes. Thanks again!

Tom

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Re: Help -- I connected my new pickups, but ...

Postby TerryTNM » Wed Dec 28, 2011 4:08 pm

Just a quick look. I don't think the outside lug on the tone control should be grounded. grounding makes it act like a volume control. I see it is on Danny's photos so not quite sure what's going on there but the Seymour schematic shows the one pole open. You might give it a try. I've never grounded a tone control pole. -Terry

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Re: Help -- I connected my new pickups, but ...

Postby raygun85 » Wed Dec 28, 2011 4:28 pm

De-solder the ground from the lug on the tone pot. The tone pot is cutting treble via the capacitor, nothing on the tone pot should be going to ground. Solder the wire from your switch to the middle lug on the volume pot and solder a jumper from there to the center lug on your tone pot. Then connect the wire from the jack to the outside lug on your volume control. That should fix everything.
-matt
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P.s. This scheme isn't classic Mosrite, but your controls will work exactly the same way.
How dare you presume to inject, using reproducible facts and rational thought, an on-topic discussion into a thread that had degenerated from sarcasm, personal invective, and hand-waving arguments?

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Re: Help -- I connected my new pickups, but ...

Postby dubtrub » Wed Dec 28, 2011 4:31 pm

Wire it exactly as in the photo above or in the diagram below and it should work fine. The photo's are original untouched Mosrite wiring. Image
Danny Ellison

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Re: Help -- I connected my new pickups, but ...

Postby raygun85 » Wed Dec 28, 2011 4:35 pm

Forgot to mention in the scheme I posted to solder your cap to the outside lug on the tone pot as well, and the other end of the cap to ground.
How dare you presume to inject, using reproducible facts and rational thought, an on-topic discussion into a thread that had degenerated from sarcasm, personal invective, and hand-waving arguments?

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Re: Help -- I connected my new pickups, but ...

Postby oipunkguy » Wed Dec 28, 2011 5:06 pm

yeah, a tone pot works by only grounding out some of the frequencies in the signal via the capacitor. the bottom of the tone pot should be grounded but none of the lugs. guitar wiring 101.
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Re: Help -- I connected my new pickups, but ...

Postby MWaldorf » Wed Dec 28, 2011 8:33 pm

Besides the circuit itself, you need to make sure that there's no unintended shorts occuring when you put the electronics back in the guitar. Try testing the circuit with the guitar strung and the pickguard off to make sure it sounds right like that, then if it sounds wrong in the guitar you know you've got some wires touching that shouldn't be.

Good luck!
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