AS3340/CEM3340 troubleshooting

Hey, I finished my first module today, it makes a noise but the main pot and the trim pot doesn’t work. The only thing that I can think is that I put a 100k trim pot in salvaged from some old school project or the cable that I was using is messed up. Ill swap it out for a 10k when i get chance. It is my first module so I was expecting something to go wrong. But i was just wondering why sound was coming out of all of the jacks - even the cv. Thanks, Sam (not lmnc my name lol)

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(there’s a lot of existing 3340 threads here, so not entirely sure you need to open a new one, but ok)

You forgot to tell us what exactly you built. The performance oscillator on PCB, the simple 1v/oct stripboard layout (if so, which version), something else? And what does “sound” mean? Random noise/hum or an actual tone?

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Could you provide us with some more info?
For example, I would like to know:

  • Can you describe the sound? Is it very low? Is the sound the same out of every jack? In that case, you probably have a bad power supply.
  • What circuit did you build? One of Sam’s designs? From the datasheet? Found it somewhere else?
  • Do you have a photo of the component side of the pcb or perfboard?

Salvaged pots are not a very good idea. Pots have a expected life span (they collect dirt, and moving parts wear out the pot. Spend an extra €2/$2 and get a new pot. It’s a lot of money (if you sum all the €2 of all the pots in a rack), but if you can spend it, it is worth it.

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(Yeah sorry I forgot to say I read through some of them and couldn’t find much)

I built Sams cem3340 simple 1v/oct vco
It makes a triangle from the triangl (I think) and a saw from the saw (I think) and it makes a saw signal from the cv. It is a tone

Saw and tri from the respective jacks (I think) and the same that comes out from the saw comes out of the cv, it goes like up and down but not like an LFO, it’s like it’s warming up and it takes a moment to get to the tone.

1v/OCT stripboard layout

Yeah I think I’ve got a new one somewhere

I had the exact same issue at one point. Just going through and re-heating all of the solder again fixed it for me.

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On my first builds I had alot of problems with my soldering. I recomend using a multimeter to check the circut for shorts. A magnifyingglass helps alot as well to check the solderjoints.