By Jon Chappell
I often break down my guitar maintenance activities into two categories: cleaning and tweaking. Cleaning covers everything from wiping the strings to dusting the metal and wood parts to using liquid polishes and fine-grade steel wool on the strings and fretboard. These processes are pretty hard to screw up, unless you dump a bottle of polish into your electronics. And if you follow simple safety procedureslike pouring the polish into a cloth first, rather than applying it directly to the guitaryoure less likely to have this type of accident.The second, deeper level of guitar maintenance involves actual manipulation of the guitars components, often using tools. This is the category of tasks I refer to as tweaks, which require a little more savvy than when performing simpler surface-cleaning routines. Ill outline some of the most common tweaks I regularly perform on my guitars. If youre not completely comfortable with making any of these adjustments yourself, just take your instrument to a recommended guitar shop or technician. Some skills, however, you can develop through repeated use, such as adjusting your intonation. Following are some good first steps that will get you comfortable with DIY repair.
If you hear a crackling sound come out of your amplifier, and its not from the amp itself or the knobs on the guitar, it could be caused by a loose jack. Because you plug your cord into and out of your guitars output jack with relative frequency, you put stress on the jack (even if youre careful when doing it), causing it to loosen over time.A loose jack at the very least can rattle and vibrate. If left untreated, though, a loose jack can cause the wires attached to it to make contact with other conductive surfaces inside the guitar, creating loud crackling pops that come through the amp as the signal periodically shorts out. And if one of the wire connections breaks off of the jack, you lose sound altogether. At the first sign of a loose jack, give the nut that holds the jack to the jack plate a gentle clockwise turn to tighten it back up, as shown in Figure 1. You may need to select a different type of wrench depending on the type of output jack you have. For example, a Strat has the jack recessed and is more easily accessed with a socket wrench. Guitars with side-mounted jacks leave the nut exposed and can be tightened with any kind of wrench or pliers.
Fig. 1. Tightening a side-mounted jack nut (above photo) can be done with any kind of spanner, including pliers and a crescent wrench. A recessed jack nut, such as those found on Stratocaster-type guitars, requires a socket wrench to tighten.
If tightening the nut doesnt work, you can remove the jack, inspect the wiring, and resolder the wires, or replace the jack all together, if necessary.
When you evaluate your guitars playability and then make changes based on that assessment, youre performing a setup. A basic setup involves changing the action (raising and lowering of the strings) and adjusting the intonation (the strings ability to fret in tune).
Action is defined as the distance from the strings to the frets. Conventional wisdom says the lower the action the better, because its easier to play a guitar where the strings are low hovering just molecules above the frets. But low action comes at a price: The strings rattle and buzz against the frets if the neck gets even slightly out of alignment or sometimes even if the weather changes. The other problem with low action is that you cant hit the guitar quite as hard with your right hand because the strings buzz. Guitarists who like to play aggressively (and there are plenty of players who do) dont like super-low action because it requires a lighter touch. So you may have to experiment to find the action that works best for your style of playing. Fortunately, adjusting the action is fairly easy to do.The simplest way is to raise or lower the strings at the bridge, either by moving saddles or the vertical studs that that bridge sits on and which anchor bridge to the guitars body, as shown in Figure 2. If your saddles follow a curve that tracks with the fretboards curved radius, be sure to maintain that as you raise and lower the saddles. The best way is to count the number of complete rotations you make on any of the bridge or saddle screws that control the height of the strings.
Fig. 2. A small hex driver (a k a Allen wrench) is what you use to raise and lower saddles on a Tele- and Strat-style bridge.
Spare the Rod
Your guitar neck is made of stiff wood, but it doesnt hold its shape all by itself. Inside the neck is a cavity through which passes a rod (or pair of rods), known as the truss rod. This rod enables the neck to flex one way or the other, raising or lowering the action (see the previous section) in the process.If your action is too high between the 7th and 12th frets, and the neck is bowed outward (scooped downward away from the strings, creating a gap), it means the neck is warped. The neck can also be warped in the other direction, putting the strings too close to the frets and causing them to buzz when you play in that region. In either case (though the high-action scenario is much more common), a simple truss-rod adjustment can fix the problem.A quarter to a half turn with the appropriated-sized wrench on the truss rod often corrects a bowed neck. Tighten (turn clockwise) the rod to correct a bow away from the strings; loosen the rod to correct a curve that goes into the strings, as shown in Figure 3.
Fig. 3. If you have a bow in the neck, you can usually correct is with a turn of the truss rod. Take the proper sized hex driver and turn the rod clockwise to correct an outward bow (where the fingerboard dips away from the strings between the 7th and 12th frets), counterclockwise to bring the neck away from the strings.
Remember that righty/tighty and lefty/loosey are the directions to follow as you face the truss-rod nut and make your adjustment. You may have to wait a few minutes for the neck to completely settle before you determine if you need to make further adjustments.Warning: Its possible to snap a truss rod that has frozen or become too tight over time, and repairing it can be very costly. On older or vintage guitars you may find that the truss rod is tight and doesnt turn or requires excessive effort to do so. If this is the case, consider taking it to a repairman or guitar shop to have it done for you. The truss rod should turn in either direction with just a reasonable amount of torque applied. If you feel undue resistance, dont force it.
The terms tuning and intonation are often confused. In guitar terms, tuning refers to the accuracy of the open string. Intonation is the strings or guitars ability to fret accurately. A fretted note on the guitar can be out of tune for three reasons:
- The open string is out of tune to begin with, but the fretting is accurate.
- The open string is in tune, but the fretting (intonation) is inaccurate.
- The open string is out of tune and the fretting is inaccurate.
A quick way to test the intonation of any string is to lightly touch the string with your left hand, directly over the 12th fret the fret wire itself and striking the string with your right hand (also called a harmonic at the 12th fret). Then play the 12th-fret note as you would normally play it. If the fretted note isnt perfectly in tune with the harmonic, your intonation is off. If the fretted note is sharp, you need to move the saddle back (away from the nut); if the fretted note is flat, move the saddle up (toward the nut). Figure 4 shows the bridge saddles and the directions they move to correct for intonation problems.
Fig. 4. A small jewelers screwdriver can be used to adjust the intonation of a saddle, turning the screws so the saddles move toward the nut (to correct for strings that fret flat) or toward the bridge.
Spring into Action
Other factors can affect whether the strings play in tune. For example, on an electric guitar with a floating bridge, the bridge springs can determine whether the bridge returns to its original, tuning-neutral location after whammy-bar manipulations. If the springs hold their tension as they should, tuning equilibrium is achieved, as the springs pull the bridge upward, counteracting the strings downward pull.The springs are located under the bridge and accessed through a cavity in the back of the guitar (shown in Fig. 5). They attach in two places: at the claw at the top of the cavity and to the holes at the bottom of the bridge. To adjust the string tension, tighten or loosen the two screws that hold the claw to the body. This will draw the springs tighter or loosen them, respectively.
Fig. 5. Bridge springs are accessed through the back of the guitar, and maintain an equilibrium with the strings, which pull the bridge in the opposite direction. You can increase the tension of the springs by tightening the claws screws, which pulls the claw further away from the bridge.
Ghost in the Tuning Machine
Everything thats put together falls apart in time, and its no different for guitars than for automobiles or great empires. Sooner or later, somethings going to give. Your tuning machines are made entirely of metal, with metal gears, posts, screws, washers, nuts, and so on as shown in Figure 6. Because most of the stress on your guitar occurs at the gears metal teeth meshing against metal teeth these gears can wear out.A tuning machine uses a particular type of mechanism called a worm gear. In a worm gear, the worm (the straight part) can turn the gear (the circle), but the gear cant turn the worm. For this reason, many guitars never have a problem with slippage, and the tuning machines last as long as you own the guitar, but if the gear parts do wear out, you should know the signs:
- The post may slip back, causing the string to go flat.
- You feel play in the tuning key as you turn it (it wont seem to engage the post).
- The post doesnt turn evenly with the turns of the key.
If you suspect a problem tuning machine, you can buy replacement tuners individually or by the set. Be sure to choose the right model and the right color (silver, gold, black) to match the rest of your tuners.
Fig. 6. The inside of a tuning machine reveals the worm gear where most of the stress occurs. The tuning peg is attached to the worm; the post is connected to the gear. By removing the cover, you can easily see the workings of the gear and what problems are causing slipping.
All Amped UpIf you practice common sense in the same way you would when approaching, say, a lamp or a toaster, you can deal with some of the common problems that may befall your amplifier. But above all, heed this warning: Your amp deals with high voltage the stuff that can shock, seriously injure, or even kill you. If youre at all unsure of how to work with your amp or any electrical appliance that plugs into a wall leave the job to a qualified technician. But heres a very simple fix that anyone can do: diagnosing and replacing a blown fuse.Amplifiers are equipped with a fuse positioned for easy access, so you can easily replace it. A fuse is a safety valve designed to self destruct at the first sign of electrical trouble. If your amp encounters a surge in current (extra electricity that could be caused for a number of reasons, such as when the air conditioning, stage lights, or jukebox kicks on), the fuse will fail, or blow. This means that the filament designed to keep the circuit closed melts and dissolves, creating an open circuit where no electricity can flow. The fuse fails because its designed to before unsafe and improper amounts of electricity can get into your amp and damage your circuitry or create a shock hazard.Its best to examine the fuse when its still working. It should be clearly obvious that the filament is fairly straight and connected at both ends of the fuse caps. Follow these steps:
- First unplug your amp, and then unscrew the fuse cap from the back panel, as shown in Figure 7.
- Remove the cap and carefully inspect the fuse to see if the filament (a thin, threadlike metal wire) is intact or broken. If your amp is working, the filament will be straight and connected in the middle
- If the filament is broken (as it is in the photo on the right), youll see a clear gap in the middle. Replace the fuse with a new one, and be sure not to repeat the conditions that blew the first fuse.
Fig. 7. One of the simplest repairs you can make to your amp is to replace the fuse. While your amp is operational, remove the fuse to see what a working one looks like. Then youll be prepared to recognize a blown fuse.
By regularly cleaning and tweaking your gear, you can actually stave off more major repairs or costly fixes almost indefinitely, if you really keep up with it. Having said that, nothing beats a trip to the old repair shop to get a thorough inspection, just to make sure youre doing everything correctly, and to get an expert eye to catch things youve either missed or cant diagnose yourself. But you can save money simply by performing these simple steps from time to time, and you also get to better learn the workings of a guitar, which brings you still deeper knowledge of your instrument.
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