#1
i have an old 3-pickup Kay Swingmaster with the three "kleenex" pickups and a 4-way switch with volume and tone controls for each pickup. when playing through an amp, there is a very loud hum. at 3 or 4 on the volume knob, the hum is louder than speaking volume. it's a low-frequency hum that disappears when i stand in a very specific position in relation to the amp.

what's the deal? is the guitar grounded improperly? or are these pickups inherently noisy?
#2
Have you cleaned the switch, pots, and input jack with Deoxit/Electronic-contact cleaner?

And without good pic's it is anybodys guess what the wiring looks like
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
#3
actually i replaced the pots, caps, and jack. the only thing i did not replace was the switch. the hum was present before i did anything, and remained after i swapped the parts. i can't seem to find an original wiring diagram online. i don't really care for the "all on" 4th position of the rotary switch, so i'm considering moving to an LP-style 3-way switch.
#4
Did you use insulated wire when replacing the pots? If not, that will cause a hum. Improper grounding at the tailpiece will too.
Good luck.
#5
the ground wire connecting the 6 pots is not insulated. it has what seems like a pretty crude grounding - a thick piece of bare solid core wire in a U-shape connected to the back of each of the 6 pots, then touching a solder terminal, which is connected to the output jack (that wire is insulated)
#6
Also have you shealded the cavity with copper tape or conductive paint? also shield the back of the pick-guard if there is one.

I'm going to guess this guitar has single coil pickups and you are getting 60 cycle hum
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
#7
i have not experimented with copper shielding. the pickups are high output single coils, on par with P90's. this is the guitar:

I can't for the life of me find a wiring diagram with 3 pickups and a 4-way rotary switch
#9
Shield all the cavities for sure. I was having issues with hum on some p90s I just installed last night. It's been a while since I've had anything passive in a guitar, so the noise was shocking. But shielding cleared the problem right up. I got mine from StewMac a while back. They sell the stuff by the roll for like $20, if you can't find it locally that is, I've shielded two guitars and still probably have enough for 5-6 more at least. Good stuff to have around.