Lyra8 DIY Voice 3 not working

[Emmanuel]

Hi everyone,

I have completed the build for my LYRA8. Everything works fine except for voice 3. I’ve explored the board with my oscilloscope and found the main osicllators (haha they are also clearly marked with numbers 1 to 8 and are the 2 smd chips on the bottom board) Im seing all of the voices oscillating with a cool squarewave except for voice 3. I’ve replaced the timing capacitor but still no luck. Its been hard to diagnose withouth an schematic but has also led me to learn a lot.

I was wondering if anyone had a similar challenge or if you have some pointers at what else to check in terms of signals to trace, critical componets for the vco, etc. Any pointer helps, really.

Do you know what kind of 4093 oscillator configuration is used in the design?

Thanks in advance!

[Flo]

Hey Emmanuel,

I have a similar problem, voice 7 isnt working. Since the IC is working, it seems like the envelope has no impact on the VCA. Did you got yore voice to run?

There is one more problem, on the messuring points Im 1V to high.

All the best!

Flo

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