If you saw my other thread I was trying to use a DPDT switch and set up a S-None type of design. Due to lack of time and the need to get that project finished, I ended up just doing a standard strat wiring with the addition of the Neck-on combination and SPDT switch. It sounds great, but still have some hum, and I'm not sure I have the grounding wired correctly. I had already shielded the cavity and pickguard, and have the ground from the trem claw routed to the cavity shield using a screw into the body.
I used the standard strat wiring grounding as follows: 1) ground wire connecting each of the 3 pots 2) All pickup ground wires are soldered to the Vol. pot shell. 3) Ground wire from volume pot shell to the volume pot lug
I am not using a star ground used in "Shielding the Beast" just did the shielding part. Am I missing something, or is this just something I should expect with this configuration?
On another note, I noticed on the pickups, there is a single hair-thin wire which runs from a solder point on one side of the pickup, over the outer edge of the bottom of the pickup to another solder point on the other side (see image). This wire is broken on at least one of my pickups, yet the pickups still work. What does/did this wire do?
I can't tell much from the photo. If the pickup is working, I'd say don't mess with it.
In order for the shielding to be effective, it has to find ground somewhere. The "star ground" scheme achieves this with a ring terminal slipped over one of the pot shafts, then tightened down together with the pot so as to make a good contact with the shielding.
If you are not using the star ground, you should still have contact through the pot shaft/shells against the pickguard- but this contact may be iffy.
To see if this is the problem, you can run a wire from the lug where you wired your bridge ground to the back of a pot. Or, if you want one less wire to disconnect when you pull the guard, you could use a ring terminal just like in the star ground scheme, but just wire it to one of the pot shells.
EDIT:If you have a meter, you can also test for this before you wire anything. Check for continuity between your pickguard shielding (choose various points) and a pot shell. You should get 0Ω or very close to it.
And, by "feedback", I assume you mean the good old hum, not actual feedback.