Pickup wiring issue...NEED HELP!!!

[johnnyoak]

Just installed 2 brand new Seymour Duncans in my PRS Custom 22. Jazz in the neck and Duncan Distortion in the bridge.

Tested the connections at the selector with my multimeter and everything reads correctly...about 7.5 for the jazz and 16.5 for the distortion.

In positions 1 and 5, the pickups are full output and the tone knob works properly, but I do get hum when my TV is on and the cavity is fully shielded with shielding paint and a copper foil lined cover...all grounding appears correctly connected.

In positions 2, 3 and 4 I am getting a reduced output and the tone knob seems to cut the gain/signal instead of adjusting the high end as it should.

Everything is wired correctly from what I can tell from using these diagrams:
www.prsguitars.com/csc/schema...5wayrotary.pdf
(it's a pre 2007)

www.blueguitar.org/new/articl...r/colorcod.pdf
(to translate color coding)

My wiring is the following:

Green -> ground -> "white" input on the rotary
Black -> hot -> "black" input on the rotary
Red/White -> soldered together -> "red" on the rotary
Bare -> soldered to tone pot

Here's some pics of the wiring:
flic.kr/s/aHsjuqeD4T

I'm not sure if it would be part of the issue, but the original neck humbucker wiring is extended using 4 conductor shielded circuit wire. All wires were soldered to their respective colors and then taped.

Any help in resolving the output issue as well as the hum would be greatly appreciated!

[JFrankParnell]

on the tone knob issue, I had that once and solved it by replacing the apparently borked capacitor.

[johnnyoak]

wow...the cap could be causing all of that huh?

what size/type would you recommend? the one now is marked 25v

[JohnH]

It's hard to check wiring from photos, but I think it is most likley a short circuit or bad connection. Since you have a meter, theres a few more tests you can do, measuring overall resistance across output to ground.

At full volume and full tone, measure the resistance in each setting. You should be able to work out what to expect from Ohms law, if you know what the pot values are and which coils are expected to be active.
I'm not sure what the 5 settings sshould be, but suppose you had both in parallel, as full humbuckers, you'd expect:

1/(1/500 +1/7.5 + 1/16.5) = 5.1k (assuming a 500k volume pot.

I believe some of your settings will be split coils, so halve the relevant values etc, if they are in parallel.

Next thing is to sweep the volume pot down from max to zero in each setting. in each case, the resistance should rise to just over 1/4 of the volume pot value (eg about 130k if you have a 500k pot), then fall to zero.

Last thing - and a very possable culprit: In every setting no matter what the volume pot position is, the tone knob should make no difference to the resistance measured when it is moved from min to max. If it does, then the cap is being bypassed, and that could easily happen in a shielded cavity if the pot lugs or solder blobs are a bit low against the cavity walls. Prising them up a bit might fix it if so.

cheers

John

[newey]

johnnyoak-

Hello and Welcome to G-Nutz2!

I think JohnH has you on the right track here.

BTW, I tried fixing your links but was unable to do so, other than your photos which are fine. The others give me 404 errors.

[johnnyoak]

www.prsguitars.com/csc/schematics/schem08/custom5wayrotary.pdf

www.blueguitar.org/new/articles/blue_gtr/gtr/colorcod.pdf

; )

[johnnyoak]

ROTARY POSITIONS

* Position 10: Treble pickup
* Position 9: Outside coils - parallel
* Position 8: Series single coils
* Position 7: Parallel single coils
* Position 6: Bass pickup

[johnnyoak]

position 10 - 16.03k - volume sweeps to 127k then to 0
position 9 - 481k - volume does not rise, just sweeps to 0
position 8 - 481k - volume does not rise, just sweeps to 0
position 7 - 481k - volume does not rise, just sweeps to 0
position 6 - 7.31k - volume sweeps to 125k then to 0

tone pot doesn't affect resistance when changing settings

[JohnH]

Thats good info - definately something strange about how the volume pot gets connected in those central 3 positions. Not sure what just now but will post again if I think of something. Its almost as if none of the pups are properly connected to it in those settings, so you only read the volume pot resistance. Tone pot seems to be OK

j

[johnnyoak]

yeah it seems really strange...thanks for the help thus far...hopefully someone can troubleshoot this and help me fix the prob cause i'd love to hear how the splits SHOULD sound lol

[JohnH]

maybe the pups are not getting grounded in those positions? It would explain the readings, and also that you get some very quiet sound induced via the hot leads only, even though ground is not reaching the coils.

[johnnyoak]

www.seymourduncan.com/forum/showthread.php?t=30655

do you think this would apply? it doesn't correlate to the wire color chart that i had though...

[johnnyoak]

on second thought, nevermind....i am just gonna throw a 3 way switch into it....it's getting way too complicated trying to work around the PRS circuit board : )

[JFrankParnell]

haha, in the end, thats what my friend did with his prs