Nuts and Bolts 4: Troubleshooting and DIY Fixes for Guitar Electronics
You love your guitar, but all of a sudden it’s buzzing and driving you up the wall. Or: you have a gig coming up and your signal starts cutting in and out at totally unpredictable times. You bring your instrument into a shop, already stressed out that it’s acting up on you, and find out a fix will cost you $50 and a week without your guitar.
Some guitar problems require professional attention, so it’s a good idea to develop a relationship with your local repair shop (they might even teach you some stuff!). Most of what I share in this column I’ve learned as a result of showing up to a shop and asking, on a whim, if they needed interns.
That said, some of the most common guitar annoyances are totally fixable at home. In this entry, we’ll tackle grounding and output jack problems, as well as how to solder. If you’re unfamiliar with guitar electronics, it might help to have read the last entry, which you can find in the last entry, here.
WHAT YOU’LL NEED
- Soldering station. For about $40 you can purchase a variable temperature station with pencil tip iron, tip cleaner and a wire iron holder (so you can rest the hot iron without burning your work surface). A good value unit is the Weller WLC 40-Watt Soldering Station.
- Solder. You want “60/40” solder. The numbers refer to the percentages of tin and lead, respectively, in the solder.
- Electrical tape. Sometimes part of the problem might be that the insulation around one of your wires is damaged, exposing the wire and causing a circuit to short out. It’s also good to have in case you accidentally burn the insulation while soldering and need to cover up the damage.
- Screwdriver. You’ll need to open up your guitar, which probably requires a Phillips head screwdriver.
- Wire Stripper. You might need to expose a longer tip of wire before soldering it. A wire stripper lets you effortlessly remove insulation to expose more wire.
Nasty buzz? Check for a grounding problem.
If you have single coil pickups in your guitar, you’ll probably hear a quiet humming when you’re plugged in, turned up, and not touching the strings. (This is the noise that humbuckers were designed to stop, by the way.) Sometimes, though, if your guitar electronics are not properly grounded, you’ll hear a distracting buzzing sound.
The diagram above illustrates something called “star grounding,” in which the back of the volume pot is used as a central grounding point for all the components in your guitar’s circuitry. This isn’t the only way to ground, but it’s a good one: it ensures that you won’t end up with more than one path to ground from the same point, keeping your signal as clean as possible.
INSPECT YOUR CONNECTIONS
Open up your guitar. One at a time, unscrew and lift up any plate that surrounds knobs and switches. There are solder joints, connecting wires to metal components of your guitar’s circuit, underneath all of these.
Look for the following “bad connections”:
- Broken wires. If you find one of these, strip a little insulation off each broken end, wrap the wires as shown, solder together (see below) and wrap with electrical tape. [wire wrapping]
- Bad solder joints. These are uneven, bubbly or lumpy globs of solder, usually connecting a wire to a component (like a lug or the back of your volume pot, for example). A good solder joint should be smooth and shiny. Reflow any bad solder joints. [good solder joint, bad solder joints (bubbly, incomplete).
- Damaged insulation. If you see any exposed spots in the middle of a length of wire, wrap these with electrical tape.
HOW TO SOLDER
Here are some helpful tips for working with molten hot lead!
- Let the iron get hot. Around 650°F is usually good. This may take a few minutes; be patient.
- Tin the tip: touch the end of your solder to the tip of your iron. This helps fresh solder flow into the joints you need to make faster.
- Heat up the metal area you’re soldering to with the iron first, then touch the wire to the joint itself, rather than to the iron. If the joint is hot enough, solder will liquefy and flow almost immediately. If you’re reflowing a bad solder joint, the only difference is that you’ll heat up the existing solder, and when it starts to melt flow a little bit of new solder into the joint.
- Turn off/unplug your soldering iron. This is important. 700 degrees is really, really hot.
NOTE: It’s best to re-tin the tip before each application. There should also be something like brass coils in your soldering station for knocking any excess globs of solder off the iron’s tip. Also remember to be careful to avoid touching your iron to any point other than where you are making a solder joint. If you accidentally do burn some of your wires’ insulation, you can probably fix it with a bit of electrical tape.
REPAIR JACK CONNECTIONS
Signal cutting in and out completely when you know you’re cable’s good? Sometimes temporarily fixable by jostling the cable in the output jack? Sounds like a loose output jack connection.
The lug labeled “tip/signal” is where your guitar signal enters the jack. It is continuous with the actual “tip” of the jack. When you plug in a cable, a connection is made with the tip and the current (your guitar signal) flows into the cable and on to the amp.
- If you lack the right size socket wrench, use a spanner (inexpensive and very handy for tightening/loosening nuts of all sizes) to tighten the nut around the output jack and test operation. If the problem is gone, great. You can use clear fingernail polish or Loctite Threadlocker to lock the nut in place to keep this from continuing to happen. Make sure you buy the type that’s removable with hand tools! If the problem persists despite a tight fit, it’s time to open up the guitar.
- If there’s a plate around your input jack, unscrew and lift it up. If not, take the nut all the way off to pull out the jack.
- Look for broken wires and bad connections to lugs on the jack. Refer to points (2) and (3) in the grounding problems section for tips on what to look for and how to make a good solder joint. Keep in mind also that the goal is to make a good physical connection. If you’re working with a loose end of wire and a lug, it’s a good idea to wrap or crimp it, and make sure to fill the entire hole.
This is by no means meant to be a comprehensive guide to grounding or soldering. If these fixes don’t work for you, it could mean you missed a spot or made a bad solder joint, but it could also be a number of other things. For example, a guitar you buy used could have had previous repair work where the wiring wasn’t done properly. If you have to take your guitar to your local repair shop for professional work, so be it!
When you pick up your instrument, never hesitate to ask the repair technician to explain what they found, roughly how they fixed it, or if they have suggestions for you to keep the problem from happening again. If this stuff interests you, you can get good enough to do some of your own repairs pretty fast. Before you know it, your guitar (or guitars) will be in consistently great playing condition and you’ll be helping your friends with their fixes.
Have fun, learn stuff, be safe. Unplug your iron!