Where can I learn the skills for Debugging?

[digitalzombie]

Mostly I'm curious how to use a multimeter in regards to testing a circuit. How to test certain things and what they should do. For example: reading the GEOFEX page on debugging, at one point in the NO SOUND WHEN ENGAGED portion it says "Verify the operation of the bypass switch with an ohmmeter". Well, where do I go to figure out how to do that? I end up getting frustrated and not getting anything done. Are there any good resources for learning these basics?

[deadastronaut]

http://www.beavisaudio.com/techpages/switches/

with your DMM set to ''beep'' (continuity)

put one lead in the middle lug of the switch and the other on the above or below lug...

you should get a beep when the switch is pressed...meaning they are now connected....and the other lug is not.

the other side wont beep until you press the switch again...

a 3pdt consists of 3 spdt switches connected together...

use the search function here ...

if you need an answer, i'm sure it has been asked...many  , many times

youtube also has many videos explaining and visually, how a lot of stuff works too...

[PRR]

How does a switch work?

It connects, or not-connects, its lugs according to how you flip it.

A basic ohm-meter will show "zero" (less than 1 Ohm) or "OL" (way high) between lugs for connects or not-connects.

With the BEEP function you don't have to look at the meter. It beeps for "low Ohms" (maybe under 100) and not-beeps for high Ohms.

[jimilee]

The skills of debugging are learned from the skills of screwing up! We've screwed up a lot! Pick the brains of your forum mates and eventually you see repetition.

[Yazoo]

One of the most useful methods I've found when debugging is to use a signal generator to put a sound wave into the circuit and then trace through the circuit. If you have an oscilloscope, which you can pick up cheaply off eBay, you can track the signal through and see where it stops - usually indicating where the problem is. Alternatively, you can make an audio probe and listen to the signal. There is an article in the wiki on this site on how to do this. You can make your own signal generator at very little cost using a 555 timer chip.

[Mark Hammer]

A big chunk of debugging consists of understanding what ought to happen. 

So, in the case of a switch, there ought to be negligible resistance between any two points that are connected in that switch position. 

When power is supplied to a circuit, there ought to be fairly close to the full measured voltage of the battery or power source at any point in the schematic where it says "V+".

If one has any sort of circuit that uses an envelope follower (autowah, compressor, limiter, noise-gate, envelope-controlled anything), there ought to be some measurable DC on the cathode (stripe end) of any diode used to derive the envelope.

If a buffer or amplification stage is receiving an input signal (i.e., something is plugged in), then there ought to be an AC signal (probably something between 1/10V and 2V) on the output pin of whatever semiconductor is used in that stage.

And so on....

Eventually, you can begin to integrate both a scope, and your knowledge of the "block-structure" of a circuit, such that you can say "If X checks out fine, or shows these signs, then I know the problem can't be situated here, and is probably in that part of the circuit."  At that point, one moves from the realm of simple signs of mere functionality, into having some insight into what the behaviour of the circuit could mean.

[cruisemates]

Here is a page of helpful articles by RG Keen: http://www.geofex.com/fxdebug/fxdebug.htm