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First Unsuccessful Build

Started by PapaKev, May 23, 2021, 03:49:18 PM

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That feeling of turning something on and it being DOA.  >:(  Pedal PCB VCR. Everything went pretty smooth during the build. Pads seemed a little fragile and small. Voltages seem to check out. A real head scratcher. Being new to this my ability to trouble shoot is poor at best. Chin up, on to the next one.


If you have a multimeter with a continuity tester, you can check for broken connections by touching one probe to part where pad is lifted and other probe to leg of part that it should be electrically connected to according to schematic or PCB traces.  If the parts are connected as they should be, the meter will make a continuous sound. Also, did you rock it before you boxed it (i.e. test PCB before putting it in an enclosure)?  It's possible the mistake has to do with the wiring or something is shorting out on the enclosure.


Post some good clear pics, maybe someone one here can help.

Troubleshooting is a pain, but at some point you will need some. A really good place to start is an audio probe. Thcustoms (link^^^) has a really cool one they sell, and DIYGP (aslo^^) has a great video about how to make and use one with some alligator clips a spare guitar cable and a capacitor.


Matmosphere beat me to it while I was typing. Here are some links.

Similarly, you could use an audio probe/signal tester to trace where the signal drops out when the circuit is engaged. If you have a spare DMM probe, alligator clip, and 1/4" jack, they are simple to wire up. You can see how to build one here: and here: // Mine doesn't have the cap on the probe, which is also in Chromosphere's video of how to MacGyver and use one on his site:

I know that DOA feeling, but the elation of figuring out what went wrong beats having it fire up the first time (said by the guy who has more than a half dozen projects still in the fail pail)...


I'm pretty new to this as well and have had that happen once or twice. These things tend to usually be pretty simple issues, like the i/o reversed, an IC in upside down (done that once or twice), or something like that. Some HQ photos of everything will help give others a chance to take a look and see if they can spot anything.


+1 on posting pics.  Don't give up, that FV-1 is worth $18!

Also, as far as learning goes, nothing beats de-bugging. 


I think I've learned more from troubleshooting than almost anything else I've done. It's ok to set a non-functional build aside and come back to it months or years later too. I usually need the morale boost of finishing something that works before I feel like pulling my hair out with more troubleshooting


Thanks all. Appreciate the comments and advice. Unfortunately I had already started stripping parts from the board. I wish now that I hadn't so I could have tried a few more things. I have the TH Probe. Haven't used it yet. Probably would have been a good one to use on. Lesson learned. Thanks again.


For bettter understanding how it works, I am sending this schematic of Adjusteble Suck Fuzz Basic. For npn transisitors. Play around it on breadboard. Mean goal is to get at output of second transistor (collector) cca 1/2 of Ub. From 4-6V DC Primary use pot GATE and maybe another ones later. Pot STAB at first set at minimum. Enjoy!
"Nudíte se? Kupte si našeho cvičeného ježka! Pobaví vás svými veselýmí kousky!"