Startocaster, bridge pickup problem

[Robert Bander]

A customer brought in a Mexican Fender Stratocaster with 1 volume and 2 tone controls  The bridge pickup was not working in position 1, but did give some output in position 2.   I checked the 5-position switch as per Les Schatten's book and all positions are giving proper continuity.  I re-strung it and now the bridge pickup is responding in position 1 but it its output is much lower than either of the other two.  Does this seem like a switch problem of a pickup/polarity problem?  Are there any additional tests that would help shed some light.  Also the only way to hear the bridge pickup in position 1 is to crank up the bass on the amp.
Thanks,
Robert Bander

[Robert Bander]

Sorry for the typo, it should have read, " Does this seem like a bridge or pickup/polarity problem?"
Robert Bander

[Tom Krebs]

Did you measure the bridge pickup output? Or try switching the leads on the bridge pickup? Might be out of phase?

[Robert Bander]

Hi Tom, I'm not sure how to measure the output. Do I measure volts or amps, and what values am I looking for? Can you recommend a book that goes through the steps? I just tapped on the magnets and listened for sound from the amp.
Thanks,
Robert

[Russell Vance]

Swap the neck pickup with the bridge pickup and see if the problem moves - from the neck to the bridge -in which case it is the pickup. Secondly, and respectfully, if you intend to fix electric guitars you will need to learn about electronics and wiring at the 101 level. If it was easy , everyone would be doing it.R.

[Paul Verticchio]

+1 on what Russell said (with the same respect) about troubleshooting basic electronics. It's a rewarding and worthwhile investment of time.

You may also want to clean & re-flow the solder connections on both the pickup and the switch. I've seen some terribly substandard soldering on "straight from the factory" guitars. A good bump can also cause a solder joint to loosen and become intermittent or non-functional. Re-flowing the joint cures the issue about 70% of the time.

I can't overemphasize the importance of good soldering techniques. It's really a 'make it or break it' skill that's too often overlooked or ignored in guitar repair.

Fixing other 'hacks' poor soldering jobs is also a great moneymaker as well as a great reputation builder.

I'm sure you'll do well (: Best of luck.

[Grahame Myers]

+2 on what Russell and Paul said :-) A tip: I have "test" pickups in my shop that are "known good" components. I know they work, and I know if I solder them into a circuit that's giving problems, and the problem goes away, then I know that particular component was (is) good. If the problem is still there, then I know that the problem lies elsewhere. In another life, I was an aircraft systems tech, and we did this every day on hydraulic and electrical systems. This type of testing is a known and good way the narrow the possibilities down. It's called "component substitution testing" in engineering, and is about the quickest way there is to find out what it isn't, on the way to finding what it is, if you get my drift :-)
Good luck with solving the problem

Grahame

[Tom Krebs]

The good news is that those pickups are cheap to replace. There are several books on the market that explain guitar electronics, and I am sure that Google could contribute even more. I usually install one string rather than tap the pickups when tracking down something like this. Russell and Paul have good suggestions. Many times I have found wires loose or non soldered joints.

[Gary Fried]

I had a very similar problem recently and it ended up being the solder work around the eyelets on the pickup. I was able to get a full reading on the pickup but it sounded thin. I reflowed the joints with some fresh solder and that solved the problem.

[Kevin Swaim]

Another thing to check, and maybe you already did, but if there is any shielding in the cavity, make sure the switch isn't touching it anywhere.

[Robert Bander]

Thanks everyone for all the tips. In a former life I wrote maintenance manuals for the electronics industry. I know the basic theory and techniques, but I was interested in those little pesky issues that are specific to electric guitars.
In terms of swapping pickups, aren't the neck, middle and bridge pickups wound differently and would therefore have different outputs?

[Paul Verticchio]

They will only have significantly different values if they are a "calibrated" set. In a calibrated set, the neck pickup will have the least DCR. The bridge will have the most. Allow for manufacturing variances on uncalibrated sets.

For testing purposes, it's really a moot issue.

Here's how to measure their individual DCR without taking the guitar apart:

Turn all volume and tone controls to "10";

Plug a cable into the guitar;

On the opposite end of the cable, attach the leads of a DMM or VOM as follows... "+" (red) to the tip of the plug..."-" (black) to the sleve of the plug;

Set the DDM or VOM to measure resistance;

Select the pickup to be measured using the guitar's pickup selector switch;

View the reading.

That's it (:

Best of luck with your investigation.

[Robert Bander]

Thanks very much Paul !