Multimeter: Guitar Diagnostics


A multimeter can be your best friend in diagnosing
guitar related ailments, and while it may not be the most exciting purchase you’ll
ever make, if you are looking to get into the world of guitar maintenance it’s an
essential tool that you just can’t do without. Most multimeters will allow you to measure
a range of electrical properties; resistance, voltage, capacitance, current, and inductance
are all featured here on my meter, and the two insulated probes allow us to do this with precision
and safety. There are many multimeters available at all
different price points, but for your everyday guitar issues even a very basic meter
will give you all tools to pinpoint your problem. Let’s have a look at some of the simple,
bread and butter uses of a multimeter that are most useful to us guitarists. For all
of the examples I’m going to talk about your probes should be connected: black to
common and red to the Voltage/Resistance input. Continuity: Continuity tests ascertain if one point is
electrically connected to another. Within the resistance settings of your meter, denoted
by the greek letter omega which stands for Ohms, the unit of electrical resistance, there
will be a symbol that looks like sound waves. Turning the meter to this setting and
touching the probes together will result in the meter making a beeping noise.
Now we can probe two points on any object and if they are electrically connected, the
meter will beep. Cables: This allows us to test things like instrument
cables. When your rig suddenly goes silent, cables are the most likely cause of the problem,
but it can be impossible to tell which cable has a fault from the outside.
Probing the Tips and the Sleeves will let us know if there is a break in the cable,
if they beep the connection is good and the cable is fine, but if it doesn’t beep then there is a break in the cable and it needs to be either repaired or replaced.
Continuity can be used to test all sorts of cables, just remember to disconnect any power
cables from the mains before you start probing them. Ground Wiring: Grounding issues are remarkably common with
electric guitars. If your guitar starts to hum really badly, or cuts out all together
then it’s very likely you have a bad ground connection within the instrument.
Using your multimeter in continuity mode is a fast way to pinpoint what isn’t connected.
Within your guitar all metal parts like pot casings, switch housings, bridge, strings,
and the shielding in the cavity itself should all be electrically connected to the Sleeve pin on the
output jack. By holding one probe on the output jack and
with the other probing each place in turn, you can work out what is connected and what
isn’t. Any problems here will likely be caused by
bad solder joints or disconnected wires. Fuses: If you have everything plugged in and switched
on but there is still no power to your amp or effects, then the likely cause is a blown
fuse. Fuses can be located on the rear panel of your amplifier and, depending on where
you live, inside the mains plug head. Probing both ends of the fuse will let you
know it is good or blown Remember to only use the fuse rated for your
device, if the device continues to repeatedly blow fuses then it has a fault and requires repair by
a qualified technician. Simply sticking in a higher rated fuse doesn’t solve the problem,
and only means the fault will go on unchecked, and will keep drawing
more and more current from the supply until the device is damaged beyond repair,
or it sets fire to itself and everything around it. Pickups: Perhaps you want to know the DC Resistance
of your pickups, pickup resistance is a shorthand way of estimating how much output the pickup
will have: Lower resistance readings mean a quieter pickup, while higher resistance
reading relate to a hot, or high output pickup. Most pickups will fall somewhere between 5Kohms
and 20Kohms, so using the 20K setting on our multimeter will allow us to measure resistances
up to that value. Probing the hot signal and ground wires will
display the resistance of the pickup. For humbuckers with 4 conductor wiring, make sure
both coils are connected so that you are reading the whole pickup.
Not only is this a great way to compare the output of pickups, but it can show a fault in a coil. An extremely
high, or infinity reading indicates a break in the coil, and an extremely low reading
would imply that there is some kind of short circuit within the pickup. Potentiomenters: Resistance settings can also help identify
which potentiometers are in our guitars. While the value is usually clearly printed
on the metal casing, this can sometimes be obscured by solder or omitted entirely.
Pot values are typically 250K for single coils and 500K for humbuckers, although 1M pots
sometimes pop up in certain places. The 2000K setting will let us see readings
up to 2000K, so by probing the outer two tabs on our pot we will be able to see which of
the 3 values our pot is. DC Voltage: Turning your meter to the section labelled
V, which stands for Volts the unit of the electrical property Voltage, and ensuring
that DC is selected (signified by the symbol of horizontal lines) we can now measure DC
Voltage. Batteries supply DC voltage to our effects
pedals, active pickups, wireless packs, your mother’s sexual aids, and more. A fresh
battery will start its life with its rated voltage, but as the battery discharges its
voltage begins to decrease until it becomes so low it can no longer drive the electronic device it
once powered. Probing the positive and negative terminals
of a battery will show us the voltage that battery is currently outputting, so you can
see if it’s fresh, or a little bit dead. Electrical components within our effects pedals will operate over the
range of a few volts, but can respond differently to different levels of supply voltage. This
is the reason some players claim their pedals sound better with a slightly flat battery,
the drop in voltage is driving the components in a slightly different fashion, producing a sound that
is different from when the battery was fresh. That’s only the tip of the iceberg when
it comes to what you can do with your multimeter. These basic tests will allow you troubleshoot
the most common problems you’ll encounter as a guitar player, and as you build your knowledge and experience, you can move on to much more complex measurement and diagnostics. If you are looking to learn more about guitar
maintenance then you really should consider subscribing as I’ll be making quite a few
more videos on the topic in the future. My parteon is also there for exclusive, secret
stuff if you wish to support me, and there are other videos you might not have seen.

100 Replies to “Multimeter: Guitar Diagnostics”

  1. I was just using my multimeter on some of my mothers sexual aids and my dad walked in. I told him I was just running experiments. I have a lot of explaining to do

  2. Colin, you sexy son of a bitch, you have the most interesting and informative guitar channel on YouTube. You should do a tube amp diagnostics video! I recently bought a used tube head, my first ever, and it's starting to experience intermittent loss of gain, and if the gain is fine, it will sometimes buzz instead. I'm not sure if it's a blown tube, a blown cap, or just a loose connection or grounding issue. There seems to be so many points of failure for a tube head that it can be difficult to pin down the exact problem.

  3. great job with this, i've got a few people to send this to. For those who need a multimeter i say a good 90% of the time you're most likely using resistance and continuity so a basic multimeter is all you'll really need. Inductance is more for pickup makers and of course capacitance doesn't help much as usually capacitor values are stamped on the sides of the pickups. Just keep in mind sometimes the placement of say ohms and all changes on multimeters.

  4. Colin, I love the fact that you're so clued up with your theory. I'm about to finish my degree in electronic/electrical engineering and your videos on these topics always help jog my memory with these things. It's unfortunately a skill not enough musicians posses anymore

  5. It should be mentioned that you can and will blow the fuse in your meter if you try to measure ohms on something live

  6. As a pedal builder and guitar tech, I can't even begin to tell you how much time and money could be saved by simply doing basic continuity testing. It's really worth learning.

  7. Thank you Colin! These kinds of videos are dynamite for the aspiring tech. I know enough to be dangerous (to turn a phrase) but it's good to have info like this at the ready. Keep it up!

  8. Now all that's left to do with a multimeter is learn how it can play video games so Bethesda can rerelease Skyrim on one.

  9. when you first changed your layout, you seemed to still be getting used to it and it admittedly made the show less enjoyable. however, now i can tell you're feeling a lot more comfortable with it all, i find myself chuckling in the same way i did before but now things are a lot more spicy and clean visual-wise! keep it up colin

  10. Thank you for this. I hope you expand on this some more. Especially the ground hum issues. you seem to have a good way of cutting through the crap and making an easy to watch video

  11. This is probably thes most helpful video for someone who wants to learn more about guitar maintenance. Great work!

  12. Colin, great video! Long time viewer, first time commenter….what model multimeter is it that you are using? It's incredibly versatile.

  13. I've love this since you had your green screen and jack daniels on shot, this channel has always been extremely informative and more importantly easy to digest great work buddy, never a bad episode.

  14. hey colin, thanks for the great summary of things you can do with a multimeter. can you show us how to measure the current draw of a pedal? thanks!!

  15. Well Colin, since you asked… I'm sure you could use it as an anal probe. Test the continuity of the digestive system. If it beeps you're not constipated ๐Ÿ˜€

  16. You can probe pickups on the output jack, with a cable plugged. The switch should be in position for the selected pickup. With volumes at maximum, the result is close enough to the pickup DC resistance.

  17. Are you gonna torture test the Iron Age picks like u said in your boutique picks video? I've been waiting so I can decide on buying Iron Age or dragonheart

  18. Dude i love your videos but i havent been watching so much since your content has become so limited. It feels like your videos are a non-fiction book instead of an interesting video about helping other guitarists be better and learn more. I mean it might just be in my head for all i know but your videos seem like youre being unnatural. To me i prefer you being completely yourself and natural. I still appreciate your videos though. They'll always be super informative and helpful. Thanks for reading my autistic screeching if you did.

  19. I've gotten complaints from various sound guys that my output from my electric bass is iffy. What would be the best way to diagnose this?

  20. Can I use a multimeter to make sure I get the best tone out of my mother's sexual aide? If you could post a tutorial on this, that would be great.

  21. 1:48 you should also test for a connection between tip and sleeve, if there is a beep like that then the cable is definitely broken

  22. Problably the best video i've seen about using multimeters, including all the multimeter videos outside the guitar realm.

  23. Need some help. My guitar keeps humming until i touch string or something metal. I used that "beep" option in my multimeter, everything keeps beeping. But still humming like hell. What to do?! Btw, it has humbuvker if that matters

  24. Need to check ground where on the input jack do I hold tip and is it the red or black lead thanks! Great video.

  25. Thank you so much for this video. I was able to fix my bass using what I learned here. ๐Ÿ‘๐Ÿพ๐Ÿ‘๐Ÿพ๐Ÿ‘๐Ÿพ

  26. Colin showing us a full eyebrow workout.~.~
    That's a great base video to get people to fix more themselves.
    At 4:00 I'd like to add that if you found the rough value, let's say 8kOhms the measurement should always be in the upper third of the range you're using. Otherwise the relative failure takes more out of the cake (percentage wise). Maybe worth it when someone is trying to replicate certain pickup values, while the values themselves aren't that meaningful. Again, that is just for fixed range meters, a lot of the modern ones have automatic range mode anyway.

  27. Hey guys, so I was playing a gig using my guitar (which had just had a checkup – incl specifically looking at grounding) and my pedal board. As I was singing I was getting shocked at same time. Decided to buy a multimeter and there's beeping from all bits I touch (without opening up) but it does seem to come in at 0.07 on the continuity on multimeter when it gets to the guitar. Basically, not sure if this means it wasn't my setup, but was the amp / mic. Does it sound like my stuff is OK to use again?

  28. Thanks for this, been getting into modding my guitars lately and Iโ€™ve had a pesky bridge ground which has been causing issues, got a multi metre but the instructions were terrible and this tells me everything Iโ€™ll ever need for using it on my guitars. Thanks Colin ๐Ÿ™‚

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