Don't fiddle with the things described in this section until you're comfortable with the idea that you know what you're doing and why you're doing it. In most cases, if you're consistently unhappy with the way your instrument plays or sounds, you'll be better off taking your guitar to a repair professional, who may even be able to fix these things while you wait. Professional repair people often spend time watching the musician play and talking about what the guitarist thinks is right or wrong about the instrument before deciding the best way to set up the guitar. Remember, you're paying the expert to do an expert's job.

Fret wire can wear out, and grooves will appear where the strings have worn away the nickel. Eventually the frets will start to buzz. Take your guitar to a professional repairperson, who will replace the fret wire with the best gauge of fret wire for your guitar. A “fret job” can add a new lease of life to an old guitar.

Adjusting the Bridge

By adjusting the bridge, you can alter the action of your guitar. The action describes the height of the strings above the fingerboard. The higher the action, the more strength you need to use to fret a note. High action can be useful for rhythm playing, when you are principally playing chords all the time. Blues players who use slides often use a high action so the bottleneck doesn't scrape against the frets.

The lower the action, the easier it is to fret the note. This can be useful for fast, single-note lead-guitar playing. Ideally, you want to set the action as low as you can without getting fret buzzing. This is really a trial-and-error process. (Bear in mind that the thickness or gauge of string you use can make a difference in playability as well.) Before you make any adjustments to the action, make sure you are using a new set of strings. Old strings can affect the action and intonation.

On most electric guitars, each string has an adjustable saddle on the bridge. Either the saddle has a screw that will adjust the whole bridge saddle at one go, or each string has an individual screw that can be raised or lowered. Sometimes it's necessary to adjust the whole bridge saddle by filing it down. This should not be done by anyone but a professional repairperson.

By changing the action, you are also affecting the intonation of the guitar. When you raise or lower the action, you alter the tension and distance between the bridge and the nut. This affects the way the strings play in tune. The distance between the nut and the twelfth fret must be identical to the distance between the twelfth fret and the bridge saddle. If it isn't, the guitar won't play in tune. The easiest way to test this is to play the string open, and then play the note or the harmonic at the twelfth fret. The notes played should be identical, though the fretted note or harmonic will be an octave higher. If the note at the twelfth fret is sharp, the string is too short and must be lengthened by moving the saddle back and away from the nut. If the note is flat, then move the saddle toward the nut.

Adjusting the Neck

Temperature changes, humidity, and age can cause guitars to swell and contract. This in turn can affect the setup of the guitar. For example, a slight bow in the neck can cause fret buzz or make it difficult to get a clean note at a particular fret or series of frets. You can sometimes adjust the neck by manipulating the truss rod. The truss rod runs down the center of the neck just under the fingerboard. Not all guitars have them (such as classical guitars), and even some that do won't allow you to adjust them. Usually you can see whether the truss rod can be adjusted because there is a plate at the headstock near the nut. Once removed, you will see a rod (or sometimes two) that has an adjustable screw or nut end. If you have a new guitar, it probably came with a truss rod wrench.

If your guitar bows out between the seventh and twelfth frets, you'll see a large gap between the strings and fretboard that makes playing the string at this point very hard. Tighten the truss rod, as you face it, by turning the nut clockwise a quarter turn. Give the instrument a few moments after each turn to settle into its new position.

If the frets buzz and the neck bows inward at the same place, you can loosen the truss rod by turning the nut counterclockwise a quarter turn at a time (as you face the guitar). Again allow the instrument to settle after each quarter-turn adjustment.

If you can't fix the problem within a few turns, stop. Overtightening or over-loosening the truss rod can ruin a guitar and make it permanently unplayable.

Loose Connections

If you hear a rattle, try strumming the instrument and touching various potential culprits with your free hand until you touch the correct object and the rattling stops. For example, a rattle might come from a loose screw in a tuning peg or a loose nut on a jack socket. It's a good idea to gather a small toolkit of screwdrivers, pliers, wrenches, and such that will fit the various sizes of screws and nuts on your guitar.

Tuning Pegs

Tuning pegs, tuning machines, or machine heads (all different names for the same thing) are easily replaced if gears get worn or a part breaks off. If more than one tuning peg is giving you trouble, it's probably a good idea to replace the whole set.

The tuning pegs screw into the wood of the head, so take off the string, unscrew the tuning peg, take the peg to a guitar store, and try to get a matching peg. Then screw the new peg into place in the same position as before.

Strap Pins

These are little buttons that you use to attach a strap to the guitar. They usually have regular screw bodies that can sometimes work themselves loose. If tightening the pin with a screwdriver doesn't work, dab a little plastic wood or carpenter's glue on the end and put it back. If you still have trouble, go to a professional. If you have a more active playing style and find that the strap comes off more often than not while playing, you may want to consider using strap locks. These specially designed strap buttons will not come undone unless they are specifically released.

Electrical Problems

Dust and other grunge can affect the electrics of your guitar. If your volume or tone controls start to crackle when you turn them, or you're getting a weak or inconsistent signal, you may have dust or something else on the control. Turn the knobs vigorously back and forth to see if you can work out the dirt. If that doesn't work, try spraying the controls inside with aimed blasts from a can of air. If all else fails, go to a professional, who will give your controls a thorough cleaning.

The crackle can also indicate a loose wire in the jack plug. Take off the jack plate and look for the loose connection. If you spot it, use a soldering iron to reattach the wire to its appropriate lug. If you're uncomfortable doing this, take it to a professional.

Replacing a pickup is not that difficult. Often the pickups that came with your guitar aren't as good as ones you could buy to replace them. Make sure you get a pickup that's the same size and type as the one you're replacing so it fits into the existing holes drilled into the body.

Make sure you know which wire is supposed to be soldered to which connection. Then seat the pickup in the cavity left by the old pickup, and screw it into place. Again, don't attempt this if you don't feel confident you can do the job.