Wiring Schematic Help for 1980 STRAT

[gizmo]

So here's one that's got me stumped...I have one of those 1980 STRAT models (where the headstock matches the body color), that has one volume, one tone, and the third knob is a switch. Combined with the pickup selector, that's 10 combinations.

I put in 3 Seymour mini-buckers to replace the single coils, and what first seemed like an easy swap has me stumped. The pickup selector combinations don't seem logical, but more weird is that some of the selections repeat themselves (e.g., first and 5th switch position=bridge).

First ... anyone have a schematic of this guitar? Fender doesn't have it on their site. Second ... any suggestions on why the wiring would be so weird? Is it as simple as the fact that I'm putting in humbuckers?

[inthemix3]

This may or may not help. I came across this a long time ago on the GuitarNuts original site.
Hope it helps

[ChrisK]

First ... anyone have a schematic of this guitar?

No.

Second ... any suggestions on why the wiring would be so weird?

Probably some weirdo like those that frequent (well, loiter about) this site probably messed with it.

Is it as simple as the fact that I'm putting in humbuckers?

It's probably completely unrelated unless you did something "sideways" when you replaced the pickups.


Did you take any digital pics of the wiring when you did the swap?

Can you take some digital pics and post them to photobucket or somewhere?

A fairly easy way to diagnose wiring is to replace the pickup coils with resistors. For instance, you could replace the neck with 1K, the middle with 2K, and the bridge with 4K. (There's a real good reason why 3K won't be helpful.)

Assuming thet the pots are 250K or so, their paralleled effect won't hamper the diagnosis.

Get/buy a male phone plug just like the end of a guitar cable, or attach the digital volt meter to the other end of a cable plugged into the guitar's output jack (you DO have a digital voltmeter?).

For each pickup (er, resistor) selected individually you should measure real close (as in slightly lower) to the value that you meadured (hint) before you replaced the pickups with the resistors.

Depending on what you measure, you can tell the pickup switching structure (except for phase).

For instance, with the exact values that I indicated (within the accuracy of the resistors used), for the indicated combinations you should read the following ("+" means parallel, "*" means series):

Bridge 4K
Middle 2K
Neck 1K

Bridge + Middle 1.33K
Bridge + Neck 800 Ohms
Middle + Neck 667 Ohms
Bridge + Middle + Neck 571 Ohms

Bridge * Middle 6K
Bridge * Neck 5K
Middle * Neck 3K (See why not 3K!)
Bridge * Middle * Neck 7K

Give it a try (or trace the wiring). Either way, the fact that it's a 1980 STRAT may have absolutely nothing to do with the switching scheme currently in place!

How many positions does the lever switch have? How many positions does the other switch have?

If you elect not to try the resistor trick and the new pickups are real close to each other in resistance, for any one pickup you will read the nominal pickup resistance.

For any two in parallel you will read half of the nominal value, and for all three, one third.

For any two in series you will read twice of the nominal value, and for all three, three times.

You won't be able to tell which pickup(s) is(are) selected, but by tapping on a pickup's pole piece with a small ferrous (?ferrel ;D) metal object such as the tip of a small screwdriver, you should be able to discern the pickups that are selected. (It does help if the guitar is plugged in to an amp when you try this ).