Troubleshooting Guitar Wiring Errors
Luckily, when it comes to troubleshooting guitar wiring, it can really only be caused by a handful of problems. Although I am still occasionally surprised by what causes these problems.
- Hot Lead is Touching Ground Wire/Shielding
When you do not want there to be any sound you use a volume potentiometer to send the signal to ground. The signal, if given the option will always go to ground which causes no signal to make it to the amp through the hot lead. By the same logic, when you do not hear any sound from the guitar (when there should be) chances are you either wired some hot lead to ground accidently or somehow the hot lead is touching ground. The best thing to do is to go over your wiring and see were this might be happening. If you have no signal at all even in all the switch positions then the problem must be closer in the circuit to the output jack. Retrace your work from there.
- Female Jack Tip is Touching Shielding
It could be that the female jacks tip is touching the shielding or that a loose ground wire touching a hot wire. This can happen in Strats easily because the cavity for the jack is quite small. An easy solution is to cover the problem area of shielding with some sort of none conductive material like tape as well as reposition the jack so that it doesn't touch the shielding.
- Little Pieces of Metal Making Connections Were They Shouldn't
One time, a single piece of steal wool connecting a volume pots housing to one of its hot lugs caused the guitar not to sound. That one took forever to find! It is also the reason why I now prep connections for soldering with sand paper rather than steal wool.
No Sound In Certain Switch Positions
This is probably a wiring mistake. It is easy to make wiring mistakes at the switch because often a diagram shows one type of switch and you are using a different type. For example, Strat switches can function very differently. If you are sure the wiring is correct then refer to the "no sound" description above. It's probably a loose wire touching ground if it's not a wiring error.
No Sound and/or Crackling
- Loose Wire/Solder Joint
The most likely cause in this case would be a loose lead wire which is touching ground but loosely so that it vibrates with the guitar causing the crackling sound as it rapidly makes and looses the connection to ground.
- Bad Jack, Potentiometer or Switch
Usually you find this out after checking your wiring a 100 times. Occasionally you'll install a faulty Jack or Pot. It happens.
Normal Guitar Sound with Crackling
- Loose or Worn Out Potentiometer
I was once surprised to find that a loose potentiometer was causing a friends active bass guitar to crackle occasionally. Oddly the sound didn't increase when messing around with that pots knob. He even ended up ordering a replacement pre-amp before we discovered that the potentiometer was the cause.
- Loose Solder Connection
This can occasionally occur if a bad soldering connection is made. The vibration from the guitar causes the connection to vibrate which causes the crackling sound.
- Steel Wool Thread Bridging a Connection Between a String and a Pickup.
Although this might seem farfetched, it has happened to me a few times. The strand of steel wool gets magnetized by the pickup and bridges a connection between the string and the pickup.
- Bad Jack/Jack Ground Connection
Without a proper connection to ground the guitar makes a horrible buzz sound. This is rare but sometimes caused by a faulty jack.
- Ungrounded Metal
This can also be caused by metal in or around the circuit which is not connected to ground as it should be. For example, ungrounded potentiometer housings. Another cause can be when a guitar is shielded improperly and a piece of shielding does not connect with the others it can cause this.
Horrible Buzz and Crackling
This can be caused by the same problems mentioned in "horrible buzz" the only difference being that the guitars vibration while playing causes the loose connection to vibrate and crackle.