What Am I Looking For With A Multimeter?

[Hendrxapprentice]

Basically im looking for a basic runthrough about how i should use a mutimeter while wiring a guitar.

[JoeAArthur]

Well, it really depends. If you're chasing down a problem, it depends on the problem.

If you're installing new pickups, it's always a good idea to check continuity - DC resistance and exact measurements aren't essential here, but to have something is. It is frustrating after the pickup(s) are installed and the guitar is strung up to find you have pickups with open coils - and this can happen with NEW pickups, more often than you would thing.

On pickups I also check for correct phasing. I use my old analog meter for this primarily because it is the only meter I have and I don't know how well it would work with a digital since I look for the direction the needle deflects.

I also check the measurement and functioning of pots. If I am installing two, like for volume and tone I always use the higher measuring one for the tone control - just my convention.

If I happen to be using an enclosed output jack or switch where I can't see what is going on, I validate the correct lugs.

If shielding the guitar, I check that the shielding foil has continuity from end to end.

Just a few uses.

[Southpa]

On guitars I've really only used mine for checking resistance and continuity, thats "ohms" , denoted by the Greek symbol omega (Ω) on your meter. You can also use it for checking battery voltages. I've also done troubleshooting for voltage output on the alternator on my truck.

The meter has + and - (pos. and neg. or red and black) electrodes. When checking resistance across any component it doesn't matter which goes where. Everything has resistance, wires, pots, pickups etc. If you wanted to check to see if a wire is broken simply put one electrode on each end of the wire and see if you get a reading. If you get an infinite (∞) reading then the wire is broken, infinite resistance = no current flow.

You can place one electrode on an outer tab and the other on the middle tab of a potentiometer (pot) to check the resistance sweep, make sure the meter is set for Ω X 1K as pots are rated at 250KΩ, 500KΩ etc. Just turn the pot shaft and watch the resistance rise and fall. You can also use your meter to check the coil resistance of a pickup by the same method. Set the meter to read Ω X1K, place one electrode on the main "hot" output wire and the other to ground. If you are buying a "previously enjoyed" pickup and want to make sure it works or verify its output strength, (they are all rated in KΩ), its handy to bring your meter along.

When I've wired up a guitar I always check everything with my meter before stringing up etc. Its a real pain in the butt to find you've wired the output jack or switch(es) wrong after doing all that work. Plug a cord into the output jack and touch one electrode of the meter to the hot tip on the other end of the cord. Touch the other electrode to pickup selector switches to make sure the switch is operating the right way. You can also check all ground connections by touching one electrode to the ground part (shaft) of the cord and touching all your ground points inside the guitar with the other electrode.

Edited September 27, 2006 by Southpa