Troubleshooting First Build - CEM3340/Simple 1v/oct VCO

DIY STUFF
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Hello, I’m working on my first project, Sam’s Simple VCO design with the CEM3340 IC, and hoping to get some troubleshooting tips from experienced builders. I’ve built the core module, and not having success with getting an output signal. I don’t have a VCA yet, so I’m running it through an interface to amplify (Fast Track C600), but only hearing a noise floor. Any ideas what might be causing this issue? I’m assuming there’s an oversight somewhere on my part. Much appreciated.

Things I have checked:

  • Resistor/capacitor values
  • Continuity testing of stripboard connections w/multimeter
  • Confirmed appropriate power voltages of +/- 12v w/multimeter
  • I also tried using it with an ES-9 interface

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See this topic, it’s written for the 1222 PCB version but a lot applies also to the simple stripboard version.

In particular, check voltages on the right sides of the two 100k resistors.

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This is a great resource, I’ll start there. Thanks!

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Update: it’s been a process of debugging and learning lessons on the fly, but It’s finished and working. Thanks for the help!

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By curiosity, what was the problem ?

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I assume an error in build quality, since this was my first project. I ended up just rebuilding the core module from scratch. Just happy I didn’t fry my CEM 3340 IC. I also ran into an issue where my standoff bracket was shorting between the power rails :man_facepalming: I guess you still have to be careful even if it’s anodized.

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generally we make some cut traces on the stripboard to isolate them from the circuit like that
active real ring modulator stripboard by sound bender copie

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