# General troubleshooting process



## danotaipano (Mar 3, 2020)

I am wondering what general process people follow for troubleshooting. I have a failed build that seems to have a grounding problem. (I can make the signal kick in by touching the leg of one of the resistors, through my body to guitar strings, input ground etc.) I am obviously a newb here and just looking at what steps others go through to start debugging something like this. Thanks.


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## zgrav (Mar 3, 2020)

is your project already in the enclosure, or are you testing it out of the box?  If it is in the box, take it out to see if it works.  Generally try to get it working out of the box first, then if it does not work in the box you can look for grounding with the parts that might be touching the enclosure.


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## danotaipano (Mar 3, 2020)

It is out of the box.


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## danotaipano (Mar 3, 2020)

A little more information on my current issue. 

I am working on a Tommy II build (P.S. it would be helpful if PedalPCB kept build docs and images for previous versions available).  

If I physically touch one of the legs of C1 or R2 while touching an active contact on the guitar (string, pickup, etc.) the signal is active. These are the second and third components before the input goes into pin 3 of the 4559 IC. 

Any help with this issue or general troubleshooting procedure would be much appreciated.


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## Nostradoomus (Mar 3, 2020)

Could you post some pictures of the top and bottom of your board?


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## danotaipano (Mar 4, 2020)

Sure, here are some photos









						4 new items by Dan Mullins
					






					photos.app.goo.gl
				




A few notes: things were pretty clean until I ran into issues, now it is messy. I swapped out C1 and haven't cut the legs off yet. I am using the TI version of the 4559 IC. To simplify debugging I disconnected the input/output/switch harness and am going in to a breadboard on the Sparkfun Proto Pedal as I work through this.


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## Robert (Mar 4, 2020)

danotaipano said:


> I am working on a Tommy II build (P.S. it would be helpful if PedalPCB kept build docs and images for previous versions available).





			http://www.pedalpcb.com/docs/Tommy.v1.pdf


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## Nostradoomus (Mar 4, 2020)

Are you connecting the SW pad wire to anything as you test? It also looks as though there may be some stray lead on your GROUND pad where your wiring harness goes. Try cleaning that up.


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## danotaipano (Mar 4, 2020)

Thanks @Nostradoomus . This is how I am testing:









						New item by Dan Mullins
					






					photos.app.goo.gl
				




I have hooked up the SW and GN where the harness goes to ground on the breadboard.

There doesn't seem to be any voltage getting to R1 or C1 which I am assuming should not be the case. I guess that would explain why it kicks in when I make physical contact with either of those. There is voltage at IC1 Pin 8, R8 and R2 which I if I am reading the schematic correctly are in the chain prior to R1 and C1. Again, I am a totally noob at this so I could have this wrong.


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## Nostradoomus (Mar 4, 2020)

I’m not familiar with the proto pedal setup, try removing all of your connections aside from your main 9V and ground at the top of the board and recheck your voltage


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## Chuck D. Bones (Mar 4, 2020)

Here are the troubleshooting steps I usually follow:
1. Visual inspection of all solder joints.  Look for cold solder joints, missing solder joints and debris that could cause shorts between adjacent pads.
2. Visual inspection of all components.  Look for part number, value, orientation and damage.
3. Check voltages on ICs & transistors.
4. Divide the search for the problem into functional blocks.  Does the signal get to the input of the 1st stage?  If it does, move on to the input of the 2nd stage, and so on.
Here is a troubleshooting philosophy that has worked well for me:
a) Look in all the easy places first.  That's why visual inspection is at the top of the list.  It requires no test equipment or electronics knowledge.  The vast majority of the time, inspection finds the problem.
b) Be willing to turn over every rock. Don't mentally eliminate a possible search area because "that can't be it" or "it's too hard to check that part."
c) Be systematic. Resist the temptation to randomly replace transistors and ICs or reflow every solder joint without inspecting them first.  Take notes of where you looked, what you found and what you did about it.
d) Consider the possibility that more than one thing could be wrong.  Sometimes multiple circuit problems mask each other.
e) Don't give up.
f) Ask for help.

When you do ask for help, post hi-res pictures of both sides of the board and all the wiring.  If we're going to help you, we need to be able to read the color bands of all resistors and the part numbers on all of the ICs, as a minimum.  The first thing we're going to do is inspection.  If you make that hard, then you won't get the help you need.  
Identify every place where you deviated from the Build Docs.  If you built a board before the build docs were published, then you are SOL until they are available.
You have to be committed to troubleshooting.  Don't expect us to do all the work.  Be responsive.  If you won't have time to work on it until the weekend, don't ask for help on a Monday.


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## danotaipano (Mar 4, 2020)

@Chuck D. Bones thanks so much for the tips and completely appreciate the need for details and high quality photos. I would suggest for Noobs like me keeping those tips sticky at the top of this forum section could be helpful.

UPDATE on my current issue. I was able to point it back to the R1 not getting power which in turn I was able to figure out was a cold joint on the top side of the board - joint looked good from the bottom but the pad is on the top. I now have a functioning board and have learned some lessons in the process.


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## Nostradoomus (Mar 4, 2020)

Sweet!


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