First pedal build problems! Help!

[simont89]

Hey all! I'm new to pedal making and this forum. I did some little mods to existing pedals before, and had no problems. However, I attempted to make a Crunchbox V1, but encountered so many problems! I based this build off http://tagboardeffects.blogspot.com.au/2011/04/mi-audio-crunch-box.html on a veroboard, so I'm just following the instructions on the board and I thought it would be rather easy. Until...

The pedal has no sound, but if I shift the vero around, sometimes I get a sound, then it crackles and dies off. I've got a video that demonstrates this strange problem.

I redid the wires for the whole enclosure, redid the solder joints TWICE on the board, checked the circuit for continuity, checked for any bridging, swapped out some caps and the op amp before, pots, jacks, etc. Every problem I thought I had, I tried but nothing worked.


The vero layout I followed very meticulously.




I don't see any bad solder joints. I even cut in between the copper to remove any possible bridges, and checked with multimeter for any bridging. *edit, saw a bad joint at the bottom left, fixed it, still doesn't work!

I get really weird voltage readings off my op amp though. It's a LM833. I changed it also, and saw mikestahlme's post here http://www.diystompboxes.com/smfforum/index.php?topic=100048.0. Followed the advice there, but it can't work too.

Here are my readings:

1. 4.74
2. 4.77
3. 2.37
4. 0
5. 4.48
6. 0.61
7. 1.38
8. 9.05

And I don't get any readings (0V) for both diodes. I swapped them out for new ones too. Their orientation is right.

What could be causing these weird values? I checked the capacitors that are connected directly to the chip and get the same values.

Help is greatly appreciated! I hope this first project won't be my last, because I really enjoy doing these stuff. So hopefully I can fix this problem and learn stuff, and not be totally discouraged to continue. Thanks!

Simon

[mthibeau]

The 100n cap at the top right doesn't look like it's in the right place, it also appears there are two extra resistors in there.

[haveyouseenhim]

I see the LED clippers are facing the same way. One has to be flipped around.

[simont89]

Thanks. I used the V1 layout and I posted the V2 instead. I updated it.

And I realised I forgot to swap the LED around. It was the right orientation at first, and I changed the poles of one but forgot the other. They're in the right orientation now, but the same problem persists. There's sound for a while, then it crackles and dies away.

[simont89]

The voltage readings of the IC chip are still the same. The LED diodes still don't have readings (in the right orientation). What could be causing the low voltage to the chip? Could it be malfunctioning? Thanks again for the help.

[LucifersTrip]

what happens to the voltage readings as you jiggle the board in the video?

[markeebee]

Looks like one of the links is in the wrong place......

[GibsonGM]

Where is the SCHEMATIC?  Part of the trouble is that we're now relying almost entirely on "VERO layouts" and some are even calling the diagram a "schematic".    Issues like this would be picked up much, much faster if people at least used the actual electrical schematic....

Not trying to sound like some old fuddy-duddy, but really - you can't know jack about how something works by following vero strips...if there is nothing to reference to, you either are lost, or have to do 10X the work to 'recreate' the circuit mentally by looking at...strips....ugh.   Plus, nobody is learning ANYTHING if all they deal with is the vero.    *shrug*

[markeebee]

^ Good point!

[smallbearelec]

Hi--

Please check out this article on my site:

https://www.smallbearelec.com/HowTos/BeginnerArticle/BeginnerDos.htm

It covers a lot of "land mines" and offers suggestions for getting un-stuck.

What you have done can probably be made to work, though IMO the Crunch Box is too much pedal for a first build. I suggest that you back off this one, breadboard something simple and make it work. Then go back to the Crunch Box when you have a success under your belt and a better understanding in your bones of how easy it is to make the one error that kills the build. The suggestion that you get the schematic if possible is right-on. Then you do the continuity test based on what is supposed to connect to what in the schem, marking connections with a highlighter, and finding mistakes in the build becomes much easier.

[simont89]

Thanks for all the help guys! Yes I was a little ambitious with this first build, but looking at the vero layout I had thought "Wow pretty easy! Don't have to learn how to interpret wiring diagrams!" I did however, learn quite a bit with multimeters, and reading the schematic. I actually looked through and compared it with the veroboard. Guess I'll have more research to do!

[peterg]

Vero boards are a shortcut - until you hit a snag! Sketching your own layout from a schematic is a great way to understand the circuit.

[simont89]

Looks like one of the links is in the wrong place......

Hey thanks buddy! I totally didn't see that error! Now it's working. I feel so dumb... 

Now I will go learn how to read and draw out a schematic!

[smallbearelec]

Congratulations!...and don't feel dumb; you got a fairly complex build mostly right. When you box it, don't try to squeeze it into too small an enclosure; give yourself room to work.

Sketching your own layout from a schematic is a great way to understand the circuit.

I disagree. Doing your own layouts has a major learning curve. It's for way down the road when you have been through a few complete builds (from other people's vetted designs) and have learned to use layout software like DIY Layout Creator. What Does work for understanding a circuit is breadboarding from a vetted schem. Start with simple ones at first.

Now I will go learn how to read and draw out a schematic!

Learning to read schems is fine, and that will go hand-in-hand with the breadboarding. Drawing, again, should be learned with software from the git-go. I have made draw programs to work, but there are purpose-designed packages for this that other people will recommend.

[simont89]

Congratulations!...and don't feel dumb; you got a fairly complex build mostly right. When you box it, don't try to squeeze it into too small an enclosure; give yourself room to work.

Sketching your own layout from a schematic is a great way to understand the circuit.

I disagree. Doing your own layouts has a major learning curve. It's for way down the road when you have been through a few complete builds (from other people's vetted designs) and have learned to use layout software like DIY Layout Creator. What Does work for understanding a circuit is breadboarding from a vetted schem. Start with simple ones at first.

Now I will go learn how to read and draw out a schematic!

Learning to read schems is fine, and that will go hand-in-hand with the breadboarding. Drawing, again, should be learned with software from the git-go. I have made draw programs to work, but there are purpose-designed packages for this that other people will recommend.

Thanks so much! I read your article and it was encouraging! Haha!

Welcome to the world of DIY pedal madness indeed!

[duck_arse]

drawing software? you mean I'm doing it wrong when I use pencil and paper?

@simont - the yellow wire, top left of your board, looks to be waving strands in a manner that can only end up bad.

[smallbearelec]

drawing software? you mean I'm doing it wrong when I use pencil and paper?

"Wrong" is too strong. (Bearish poetry) I suggest learning to use a draw program out of long frustration with erasing the inevitable mistakes. Also, since I want to post my work for others to follow, it has to look clean.

[duck_arse]

for drawing circuits, I only like a piece of paper after at least the top half has been removed by pencil erasering. nice, thin, soft and no nasty glare. for vero layoutsing, I have no choice, the first time is never small enuff.

paper is just less inconvenient for me for layouts and circuit scribbles. circuit diagrams go into eagle at some stage, but due to various linux versions and updatings, I haven't started w/ vero layout progs yet.

[peterg]

for drawing circuits, I only like a piece of paper after at least the top half has been removed by pencil erasering. nice, thin, soft and no nasty glare. for vero layoutsing, I have no choice, the first time is never small enuff.

paper is just less inconvenient for me for layouts and circuit scribbles. circuit diagrams go into eagle at some stage, but due to various linux versions and updatings, I haven't started w/ vero layout progs yet.

+1. Except for the software. Still on pencil and paper!