Need help!

[michaelgard]

Hey geeks, I bought a multimeter to test stuff. I have no idea how to use it. I want to test a box of used potentiometers, Caps, switches etc to see if they work properly. Could someone draw some pictures of pots etc showing what I connect the multimeter terminals to and what all the multimeter dial settings mean. I know that 240v can kill and sticking a 9v battery on my tongue causes excessive dribbling but that’s the limit of my electrical knowledge. Any help from a knowledgeable soul will be greatly appreciated.
Ta in advance.
Mike

[JimC]

Post a photo of your multimeter so we can be specific.
Mostly all you need for guitar electronics is resistance, which will be the section marked Ω (&Omega). There will be a number of ranges against the Ω, usually the next largest than 500K is the right one. A continuity test is also useful.

[PJSprog]

Whenever I need to know something I don't know, I have two sources I always check first; I either consult with The All Knowing Google, or I attend The University of YouTube.

Here's a decent YT video on the basics of multimeter use.

[Dacious]

$20 Aldi meter? Actually good value for money, will do everything you need

Here's a good guitar specific one. You only need to measure ohms - also handy for working out speaker impedance.

https://youtu.be/61jeNmYD9-g

I have 4, a $10 one in my gear case with tubes and my spare strings etc. Plus a couple of semi serious ones. Just diagnosing a reverb issue with my 4210.


My best is this 1960s AVO ex-RAAF aircraft mechanic unit I bought for $20 off fleabay It's still dead accurate - from the days planes had tubes



If you ever need to measure anything high voltage remember to play the 'one handed tech'. Clip a lead onto earth, and use one hand only with the positive probe.

Two probes one in each hand forms a neat path direct through your heart. Very easy to give yourself a 'reverse jumpstart' and finish your career in electronics early.

[dave.king1]

Whenever I need to know something I don't know, I have two sources I always check first; I either consult with The All Knowing Google, or I attend The University of YouTube.

YT has some seriously deep stuff, I taught myself a heap of Cisco Telephony stuff over the years so I wouldn't have to keep going back every year and do a full course just to learn a few release updates, yeah I was certified ( and should have been for using the stuff but the dollars were good )

[michaelgard]

Post a photo of your multimeter so we can be specific.
Mostly all you need for guitar electronics is resistance, which will be the section marked Ω (&Omega). There will be a number of ranges against the Ω, usually the next largest than 500K is the right one. A continuity test is also useful.

This my multimeter.

Ok, having burnt 4 fingers of my left hand, the wiring is now soldered. A mess but it it what it is.
I know zero about electronics. Treat me as a 10 year old farmers boy. ☹️ Do I need to know what continuity and resistance mean?

[Simon Barden]

It helps.

Continuity is a term indicating that there is a continuous electrical circuit between two (or more) points on the circuit. It may be all just wire connections with a switch in the middle, in which case you’d only get continuity (and a beep from the meter on the continuity setting) when the switch is in the relevant position. On more complicated circuits, the circuit may involve other components in the circuit, and the beeper probably won’t work and you’d have to check relevant meter readings or pass a test signal through the circuit and test it with an oscilloscope or audio probe. But for guitar wiring purposes, it’s normally all about making sure all the bits of wire are connected correctly with no missing link or bad solder joint.

[Dacious]

Okay - continuity is just checking your bit of wire or component is connected. Put your probes on the ends of a bit of wire - that's continuity. Normally you might measure between solder joins.

Here's measuring pickup resistance via a guitar lead. Neck pickup selected, can see my meter set to 20k and probes held to centre tip and sleeve of the cable it's showing 7.2kohm which is roughly right. Even with your tones and volumes set to '10' measuring pickup DCr (direct current resistance) isn't ideal this way because switches and controls and cable can throw the result. Normally you wouldn't hold the probes to the contact like I am with my fingers either. Your body is 30% water so it is slightly conductive - why you can electrocute yourself very easily.



Whats black and hangs from the ceiling? Careless electrician.

Just a soldering tip, 'tin' all your component or wire joint points. Melt some solder onto the tip of your iron, then hold it to the each bit you're going to join so they have a bit of solder on them. Then when you hold them together and heat them, touching a dob more solder on helps them melt together. Then hold for a few more seconds - don't blow on the join. You want a nice smooth chromy looking join.



This is Marshall factory soldering from 1983, all the joints here are serviceable, but the two bottom ones are not perfect, the lead isn't 100% enveloped. They are all smooth shiny blobs

[michaelgard]

Thanks for the tips Dacious. I’ve been struggling for years to solder. I just can’t hold the wire and the solder and the iron all at once. It does my damn head in - not to mention burning my fingers all the time. Now my hands shake so much and my sight is terrible I’m getting to the point of giving it up. I have all my components mounted in a stiff piece of cardboard in the required layout for my guitar wiring. But I still have trouble holding everything still for the soldering. Their must be some “third hand” type tool that allows for easy soldering. ???

[michaelgard]

Right. Thanks Simon. I’ll watch the instructional video again - a few more times.