Project Strat pickup install done haywire

[MontyS]

Hi all. An amateur is having a breakdown. I'm working on a project strat, in which I just replaced a dead neck pickup. I haven't strung it up yet but I am getting the same, overly high resistance reading off of all of the pickups now. The pickups are single coil, regular strat pickups that should read in the 6-8k zone. I am testing off of a lead plugged into the jack. Each pu is reading around 11k and doesn't really appear to be changing it's reading as I switch through the pickup settings. Wondering if this might be the selector switch taking a crap. Any ideasand/or help in mitigating my ignorance is greatly appreciated! Thanks everyone.

[curtisa]

Moved to Tech Area -> Electronics Chat subforum.

[curtisa]

Do the pickups actually work OK?

They may measure high at the output jack, but you're also measuring the volume and tone pots at the same time by doing so.

[MontyS]

Yes. The pickups do appear to be functional. Tested with multimeter at the eyelets and also at hot/ground connection points and got the resistance readings I was expecting( about 8k @ bridge and 6.5ish @ neck and middle). When I plug in it's pretty loud when I tap pickup pole pieces with screwdriver on bridge and neck but the middle is silent, even though I am certain that it is wired to the correct lug per diagram with decent looking solder joints, to boot. However, when I put a cable in the guitar's jack and test from there, I get this high reading (11.4k) that doesn't shift a bit when I move through the different positions on the selector switch. With all this, how likely do you think it is that I need to replace the switch? Btw, sorry if I posted in wrong forum and thanks so much for the help.

[Tim37]

Did you check the "dead" pickup with your meter?  Pickups don't just go out its usualy a switch, pot ,bad connection.  

[MontyS]

Yes, I've tested the silent pu at the eyelets and got the expected reading.

[curtisa]

Does the switch select the correct pickups when moved to each position or are you also getting unusual pickup combinations too?

A silent pickup that reads OK resistance-wise suggests that the pickup is being shorted out or not being selected at all when the switch is moved to the appropriate position (wiring error at the switch).

11.4k ohm reading at the output jack almost sounds like the reading you'd get if you wired two pickups in series plus the resistance of the volume pot (again, wiring error at the switch).

Assuming you're using a 250k volume pot and two 6k pickups have accidentally been wired in series somehow, the equivalent resistance looking back into the jack would be 1/((1/(6k + 6k)) + (1/250k)) = 11.45k ohms, which is pretty close to what you're reading.

If the 8k + 6k pickups were accidentally wired in series the equivalent resistance would rise to 13.26k.

Some pictures of your wiring and the diagram you're using to wire it up with would help narrowing the fault down.

[MontyS]

Yes, the pots are standard 250k types. Here are some pictures. My camera is terrible so not sure how much help  the pics will be but here goes:

[curtisa]

Not sure how much help I can offer, sorry.

The switch looks unusual, not a standard 5-way mechanism. Is that a Schaller 'E' Megaswitch? In the last pic there is what seems to be an extra black wire on the end-most lug of the switch (marked as '7' in your diagram) - where does this go?

There appears to be a 4-conductor lead terminated near the volume pot, with red and white conductors soldered together under some red heatshrink - are you sure that one of those pickups is a true single coil and not a stacked humbucker?

[MontyS]

I believe the middle and bridge pickups are SD STK stacked noiseless single coils, to the best of my knowledge. The neck pu is a standard fender, single-coil neck pu. The switch is definitely some kind of Schaller but has no other markings on it to further determine which one. As far as the extra black lead on lug 7, I assumed it was maybe a jumper wire to give the bridge tone control but not sure. It was like that when I received the guitar. It is also wired that way in the diagram I posted. Oh well. Thanks for taking a look.

[curtisa]

Only suggestions I can offer:

• The Seymour Duncan STK-S1 pickups are indeed stacked singles with a four-conductor cable. The usual wiring for these is black = hot, green goes to ground and red+white joined together under heatshrink. Note that these wiring colours will not directly match the diagram you posted and you'll need to do some translation between what is drawn and what gets physically wired.
• The switch (if indeed it is a Schaller E Megaswitch) is a relatively complex beast, and probably overkill for what is really just a standard Strat wiring scheme. As drawn in your diagram it should work, but the assumption is that the switch actually is the one specified in the drawing. Replacing the switch with a known working one and rewiring the guitar as a standard 5-way Strat (ignoring the 4-conductor STK-S1 cables) will at least remove one level of uncertainty.
• The extra black wire from lug 7 to the tone pot will have the effect of adding whatever pickup that tone pot is usually used for to the bridge pickup every time the switch is moved to a position that includes either the extra pickup or bridge positions, which if the switch is working correctly will be 4 out of 5 positions. There isn't enough fancypants switching going on to allow the tone pot to be applied to the bridge pickup without cross-connecting the adjacent pickup as well. This could account for the static resistance you're seeing when measuring back into the jack while moving the switch across each position.

 

15 hours ago, MontyS said:

It is also wired that way in the diagram I posted

I assume you mean the extra black wire. I can't see this in your diagram. The only connection I see to lug 7 is a jumper from 6 to 7 and the hot lead from the bridge pickup.

[MontyS]

Yes. Sorry. I misunderstood and misspoke a little. The extra black wire from lug 7 to tone was there when I opened up the guitar and is not on the diagram. I was confusing this with the jumper wire (white) for some reason while not looking at the diagram.. Brain fart! So, CurtisA, are you saying I should remove the black wire going from lug 7 to tone because it is not doing the job of giving tone control to bridge, anyway? And could also be part of the problem? Also, I'm thinking of replacing the switch for standard fender-type 5-way regardless of whether or not this one still functions. Just to prevent confusion down the road, which I can empathize with considering this is basically a learning project for me and have been plenty confused already.  Appreciate the help!

[curtisa]

12 hours ago, MontyS said:

So, CurtisA, are you saying I should remove the black wire going from lug 7 to tone because it is not doing the job of giving tone control to bridge, anyway? And could also be part of the problem?

The extra black wire won't be helping untagle why the pickups aren't working as expected, so you can safely remove it as a first measure.

It's unlikley to be the reason why the middle pickup isn't working though. If the middle pickup measures OK but has no output when the selector switch is moved to the appropriate position it's likley to be an error in the wiring of the pickup, an error in the wiring of the switch or a faulty switch. If it were me I'd eliminate the cheaper faults before plonking down cash on a new switch.