Build Your Own Clone Message Board

Hey guys,

I have a student who's built a Lil'Echo that is not echoing. The dry through is fine, so the op amp splitter and summing circuits are working properly. I traced the input with an oscilloscope to pin 1 of the reverb chip. I'm not getting anything out of pin 28 of the reverb chip, which is exactly what I'm hearing.

I've trace back through the parts and tested voltages for power supply and off the pots and am not finding anything that is obviously wrong. I'd appreciate some additional eyes on the board to see if I can get some help tracing out the problem. Thanks.

Hey there!

From our standpoint in trying to help builders troubleshoot across the internet, we typically want to see certain things addressed before zeroing in too far on a particular issue. In this case the build quality is, respectfully, fairly low, with a lot of potential issues due to poor solder joints and melted wire insulation. And over the years, we've seen that soldering issues cause the vast majority of build failures. Simply correcting that very often clears up the problem. So, we would point the builder to these threads for guidance:
http://www.byocelectronics.com/board/viewtopic.php?f=9&t=52188
http://www.byocelectronics.com/board/viewtopic.php?f=9&t=52211

I would encourage your student to take another pass at the soldering on this build.

Beyond that, I'd focus on the components that support the FV-1. You mentioned that you tested for power supply. I'm not sure if you just looked at supply voltage, or if you also tested the 3.3 volt rail. I'd also make sure that all the ground points are grounded, check for shorts across components placed closely together (the crystal looks like it could be shorted).

Also, just to note, this is actually the Lil' Reverb circuit; not the Lil' Echo. I've edited your thread title to reflect that.

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MasterDelayer/Reverbrador/Ampaholic/TopJacker

Thanks for changing the title. You're right. I have too many projects going to track everyone!

Yes, the solder is ugly, but I haven't found any bad joints yet. I can have him reflow everything, with a little help from myself.* I was mostly hoping I could isolate an issue with what I have. If I knew this IC, I could probably do that quickly, but I'm not familiar with it. I did check the 3.3 off the regulator, and the voltages at the pot and into the reverb chip. I had concerns about his pot connections and did have him fix some of those. I honestly thought that was the issue, but it's not. Actually, I started with concerns about his parts locations, but after going thought it, I didn't see a wrong part.

* Everyone seems to "pour" solder on their first time, no matter how many times I tell them not to do that. Could be worse......someone else soldered their entire first board with all the components raised an inch off the board, while I was off elsewhere!