Introduction:

Although most guitar repair people offer repair to the electronics of your instrument, there are few who understand the subject to the level that I do;  Basic electronics skills are not enough, once sound is added to the mix.

Starting with a degree as an electrician, I have moved on to electronics, and have built sophisticated devices related to frequency measurement, control and manipulation for research and Industry, including custom microwave spectrometer parts and circuitry for major universities and clinics, and even a one of a kind light spectrum analyzer for Penn State.

Everything from electrical buzzes to radio crosstalk can be transferred via your instrument and other equipment, to your ears, and some are more mysterious than others.  Every touring musician with electronic equipment has most likely had encounters with strange sounds that appear and disappear as they move from venue to venue, and I have often been asked to remove electrical noise from an instrument, that did not come from the instrument itself.  I may be the only luthier who makes house calls, in order to investigate what part of the wiring or appliances in your home, studio or club are causing annoying and unwanted noise.

The following paragraphs discuss topics concerning the electronics of your instrument including those having nothing to do with the instrument itself, and how they are best dealt with, and here I will get into typical factory circuits, but there is so much more on the topic, that I will refer you to the customization section of this site quite often.

Controls:

The potentiometers (volume and tone controls) and switches, will eventually wear out, and can cause problems.  Everything from noisy operations, intermittent sound, or no sound at all when operating these controls, may be the case.  Physically loose controls can cause broken wires, but that will be discussed under the wiring topic further down.

In the rare case that they are just dirty enough to disrupt contact, or slightly corroded, cleaning them may be all that is needed, but that is hardly ever the case.  The only time dirt or slight corrosion is an issue, is when an instrument has been stored for a long time (many years) without being played.  In many cases cleaning contacts is not possible, or will not suffice.

Both potentiometers and switches rely on spring tension in order to perform well, and due to something called metal fatigue, once warn it is not enough to just bend their contacts back, as they will normally fail again within a few days, so replacement is in order.

When it comes to replacement, there are not only choices in quality, but also in function to be considered, such as switches that allow for more pickup combinations, and potentiometers with differing rates of control.  This is where we venture into the realm of customization, a topic you should read up on, as you may wish for something other than what Your instrument is currently equipped with, and if repairs are already needed, now is the time to consider changes.  Replacement of components is simple and fairly quick, and takes around 10 to 15 minutes each, but up to 40 minutes for complex switches like the "Mega Switch".

Magnetic pickups:

There is very little that can go wrong with magnetic pickups, since they have no mechanics other than their mounting hardware.  Should one of them not work, it is most likely due to something else, unless hit with enough force to cause physical damage that is visibly obvious, or your little brother found a way to plug Your guitar into the house wiring, and fried them.  In the rare case that you should need a new pickup or two, they are easily installed in under 30 minutes.

It is sometimes the case that a client wants to use used pickups from one instrument in another, and the wires are to short, so the leads have to be replaced, since splicing shielded wires is a bad idea for more than one reason, and with pickups that do not have shielded wires to begin with, replacing the leads with shielded ones may reduce a bit of noise.  Some pickups have contacts that allow for wire replacement, some don't.  In cases where there are no contacts, the enamel coated wire used for pickup coils is so thin that attaching new leads is destined to failure without proper tools and precise skill, and can get so expensive that replacement is your best bet.  I can add new leads to old pickups with contacts and that takes between 20 and 40 minutes.  I can also add new leads to old pickups without contacts, but that takes from two to four hours, and I can not guaranty that it will work, although I have had success with it for the most part.

Piezoelectric pickups:

There are two ways you may encounter piezoelectric pickups, one being the contact type which are surface mounted, and the under string type, which are either under the saddle of acoustics or encased in the saddles of electric instruments.  Piezoelectric pickups are pressure sensitive, and react to the pressure changes in what ever they are mounted to.

These pickups being made of ceramics can crack, or have their leads damaged, and will show signs of trouble, when installed incorrectly on acoustic instruments, most notable is uneven volume for different strings, when the surfaces of the bridge and saddle they are sandwiched between are uneven, although newer more flexible and therefore more forgiving models are available.  Replacing an under saddle piezoelectric pickup can take around 20 minutes, adjusting the saddle to make one work right around 10 minutes.  If the old saddle will not do, please see the acoustics topic for an idea of what to expect.

A surface mounted piezoelectric pickup may take from 10 to 40 minutes depending where it is, and the ones embedded in single string saddles of electric instruments can take from 30 minutes for one, as the bridge must be taken off and apart, but only 5 to 10 minutes for each additional one.  They are not always available single, but rather in sets.

All piezoelectric pickups rely on preamps, in order to buffer their high output and better control their tone, and there is more that can go wrong with the preamp than the pickup itself.