Best way to troubleshoot a breadboard project

[jfrabat]

Hi guys.  I hope my question is not too idiotic (I am a newb, but I have always followed the motto that the only stupid question is the one that it is not asked), but what is the best way for one to check breadboard projects?  Following the sound signal with an audio probe?  Measuring with the multi-meter?  If so, how do I calculate

To give you some background as to how much of a rookie I am, I have only completed 2 pedals, both are overdrive.  One is a simple transistor based one that is just fantastic (I use it all the time).  The other is a more complicated OpAmp and diode based one, but that one I do not like the sound.  It works, but I don't like the way it came out.

I have as a project now a Little Angel Chorus done on a PCB, but for some reason, the dry signal on that one is working, but the wet is not.  I also tried a Vulcan Rat, but took it off the breadboard because I did not get it to work (of course, as I was finishing taking it off the breadboard, I noticed I was plugging the amp to the input and the guitar to the output, which does not help in any way!), and last night I breadboarded a Deep Blue Delay, but I also could not get it to work (I have yet to do any troubleshooting on that one, and to be honest, I did little troubleshooting on the Vulcan Rat because I figured I needed the Delay more, so I did not follow up on the cause of the problem).

Now, even though I am getting a bit frustrated, I am not easily discouraged (my wife tends to call that trait "stubborn"!), but I figured there have to be some tricks of the trade to find out where the problem is occurring, and I was wondering if you guys would be willing to share them.

By the way, I have not received anything but great support from this site.  I am really glad to have discovered it!

Felipe

[pervyinthepark123]

I would follow with an audio probe. I'm also new though and have had some trouble with most everything so far, including breadboards.

[duck_arse]

testing on the BB is the same as testing in real life. use your meter to check the voltages at "the usual places", sub-system by sub-system. this will tell you the static conditions, and (along with the circuit dia and Mr Ohm's law) give you an idea if they are close-to-working or something-is-wrong. then shove signal in at the input, check for something at the output. you KNOW the sub-sections are working, or should work, because the voltages were ball-park, so if no output, it points to a problem with the interstage connects, like capacitors (and pots, switches, GROUND connections). you can then use the audio probe to narrow the problem to one of those interconnectings.

[GibsonGM]

Yes.  And a very common (most common?) issue with the breadboard is that 2 components are touching each other and shorting out! 

[PRR]

Electricity is funny because you can not see it.

A traffic-jam, you trouble-shoot by walking around to see where cars are moving and where they are stuck.

Another issue: traffic jam, you usually know the roads DID work once. However if you just built a superhighway and forgot to put on any Exits, it never worked. But eye-balls will lead to this conclusion and suggest a solution.

"The upstairs faucet isn't working!!" You can't see water in pipes. Here you would probably try the downstairs faucet. Another point in the same system. If that works but not the upstairs, you have probably narrowed-down the problem. If all faucets dry, go to the meter and loosen a joint. If your feet get wet, you have water at the meter, the problem is inside. If the meter is dry, go along the outside pipe, tapping or drilling, all the way to the well or city-tank, to see how far it is dry.

Drilling water pipes is wet work. Fortunately electricity does not leak as eagerly, though you do need a Meter or Amp/Speaker to tell if the wire is "wet" or "dry" with electricity.

You also need a general sense what to expect. If the water comes out very weakly, you "have water" but not enough pressure. If it comes out like a pressure-washer, you have a different problem (unlikely in city-water, but could happen on my pump).

In audio circuits, you need power (both sides) going to devices. Like a Sink has water from faucet and a drain taking water back to Mother Earth for re-use. You expect a 3-pin device to have one pin roughly half-way between power and return, and the other pins close in voltage and near one or the other. If you find a transistor at 9.0V 8.9V 8.5V, it is like a sink with no drain-- it is filled up to the rim.

[stallik]

PRR, your analogies are so cool!

[bluebunny]

PRR, your analogies are so cool!

That'll be a problem with the hot tap, then.   

[stallik]

 

[deadastronaut]

open the schematic in a graphics prog.

and follow the schemo from left to right, marking off (drawing)

each part and connection that you have made.....

its easy to miss a 'node (connection) ...

but i find this to be 99% bang on..each time.

(watch for breadboards that have a split in the supply rails)

use a continuity 'beep' meter to make sure you have those rails sorted..

and you should be good to go.. 

[PRR]

This trouble-shooting synopsis is actually about a computer, but the high-level over-view is spot-on.

In diagnosing a system problem you use whatever tools are available to look at various points in the chain in a methodical fashion. Like a binary chop - you start at both ends and then narrow the gap between the points until you have isolated the failing area.

It can be hard work nowadays - as it is often difficult to gain access to the optimum points.

In this case an analysis of a Wireshark capture would show how much of the PC/Router's traffic was as expected. If the PC failed to behave in the expected way at any point then the investigation moves towards, or inside, the PC. The router may still eventually be the culprit - or like many system problems it may be a case that both ends are at fault in some way.

You also learn to be wary that diagnostic tools can tell porkies under some circumstances. That's where experience counts.

The old saying is still true: "Don't believe anything someone else says they have seen - and only believe half of what you think you have seen yourself".
http://forums.theregister.co.uk/forum/3/2016/12/09/mysterious_windows_10_networking_bug/  -- comments