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Monday, March 20, 2017

A Weak or Intermittent Signal in an Electric Guitar Circuit


I bought a Fender Strat  guitar a few months ago. After I received it I have a problem concerning the five way switch intermittently working.  I used it for awhile to see if it would clear up. The switch works much less now. I have to mess with it just to get it to work and then at times it will work but at only very low volume. I try moving it thinking there could be a sweet spot that the switch will work and sometimes it is there and sometimes not. What is the problem?..........Thanks, Marco


What you're describing doesn't sound like it's necessarily a switch problem. It could be one of several common circuit problems. 
It sounds more like a wire coming loose from a soldered connection and making partial contact and thereby creating a weak signal leading into the amp. But let's look into other causes.

The 5 way switch has 5 connections typical in a Strat pickup configuration.

Each set of contacts in the 5 way switch can be in one of two states: either "closed" meaning the contacts are touching and electricity can flow between them and the pickups are selected, or "open", meaning the contacts are separated and the switch is nonconducting and that is the pickup selection that is "off".

The switch mechanism actuating the transition between the pickups. 
It may be possible that one contact is not working correctly, but it is extremely rare when there is a problem in "every" position of a 5 way switch.  That generally indicates a weak signal flowing somewhere in the circuitThis may lead to the conclusion that it's the switch but it could be a weak signal somewhere in the circuit causing the interruption. 

Most specifically let's say there is a weak signal to the amp because the circuit is incomplete or weak. 

A weak or intermittent signal in any electric guitar circuit can be caused by any one of the following several things:

1-a bad cable from the guitar to the amp
2-a ground wire out of place intermittently touching a hot wire
3-a loose wire
4-a cold solder joint
5-a wire that is only connected by a thread
on one of the multi-strands of the stranded composition of the wire
6- wire on the output jack is loose or barely making contact
7-not enough tension on the tongue (hot) contact on the guitar output contact
8-bad switch
9-poor solder connection to the switch

These are the most common and easily fixed guitar problems.
It is possible that a solder joint just needs to be re-heated, or a
wire is just hanging by a strand or two and needs more contact.
Any of these can mimic a broken pickup a broken switch, a bad pot etc.
Maybe the switch is fine after all. Take a look and tell me what you see.