Years ago, I started building this kit, and was never able to get it working because I had a problem with 5v shorting to ground. Was never able to figure it out so I put it aside. Here’s the thread on it:
Came across it recently and decided to give it another go. So I was actually able to find the short! I’ve successfully checked all the voltages in the troubleshooting section and they all look good. Now, the unit powers up successfully. I can adjust the LFO speed and see the LED reflect that change. I can start/stop the sequencer, and get some drum beats going. However, I can’t get the VCO working properly. I did the signal troubleshooting, and points E, F, G, H, I, J are all silent.
Strangely, I can get some sound under the following condition: sub-oscillator switch in bottom position, sub level all the way up, and filter mode switch in the low pass position. In this case, when I hit run/stop, I do hear an oscillator going between two notes (although very quietly…I had to turn the input up quite a bit on my audio interface to hear it). Changing the glide knob applies glide to the sound, and changing the octave/master tune has an effect as well, so it does seem like I’m hearing some kind of oscillator. When this is running, I can also hear the sound at output K (mixer out). You’d think this is the suboscillator I’m hearing, but even when this is occurring, I and J (and all other osc outs) are silent! Playing with the filter doesn’t seem to have any effect either, and I can’t get it to self oscillate.
Really confused about where to go from here to continue troubleshooting. Any suggestions?