blinkly blinky little light,
looks like you fried duino tonight.
Try hooking up the duino to your computer and see if you can still load the code to it. Check the serial monitor for any errors.
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Update! 
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So what did you end up replacing? The TL074, obviously. The Arduino as well?
(and while we’re doing a post-mortem, maybe @lookmumnocomputer should change the connector for revision 2 
)
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I did the same thing while messing around and testing. Fried the 72 and the 74 in about 5 seconds. Arduino and everything else fine. I got a little piece of tape over that sync connection now =]
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welp - it worked for about 20 minutes.
i placed it in my rack and it was working as shown in the video - come back 20 minutes later and i changed the octave and then the screen jumped through a whole bunch of notes, then a single dot down on the lower right site, then went blank and now the sound is friggin god awful.
so - back to being perplexed again lol…
I am gonna order another AS3340.
TBH, having to use that SOIC adapter is what I believe is causing some of these issues.
That actually sounds like it might not be getting enough power. Mine does that when I plug too much into one (underpowered) supply.
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yeah - i think you’re right - went to plug in my wallwart just a few minutes ago and now everything is dead.
pretty sure i toasted a power plug or power supply.
gotta order another plug to see -_-
great morning… lol
I’m a modular noob, wondering what the difference is between the 1v/oct and CV input is and also how does the sync work? And the sync on the LFO for that matter
what the difference is between the 1v/oct and CV input is
Same thing – they’re added to each other (and to the octave selector and tune controls) to produce the internal frequency control voltage.
how does the sync work
It resets the oscillator, which lets you use a second oscillator to mess with the waveforms produced by the first one. See the diagram over here for how positive and negative sync pulses affect the waveforms.
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Thanks fredrik. So would you patch the two oscillators sync jacks together or run the wave output of one into the sync jack of the other?
The sync jack is an input, so you’d patch the output from one oscillator to the sync input of another.
Also note that the 1222 performance VCO uses the same approach as the 3340 example schematics, with a small capacitor on the way in, so it expects a square/rectangle wave (e.g. PWM) and will sync on both rising (positive spike) and falling (negative spike) edges.
Oh how I really want that 0 Coast you have there on your shelf!
lol, well it normally doesn’t live there, I had it out when I was testing the VCLFO and Filter as I wanted something that I knew was ‘good’ and would output signals when I wanted it to but was small enough to move around. It was actually super useful in working out that all the different parts of the circuits were behaving as they should, especially the mixer section for producing some control voltages from the offset.
Normally it lives with my euro…
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how do you like your Thomas Henry VCO’s? I was thinking about making both it and the bass++. You also have the subPhatty, which I also want very much!
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Yeah, I do love my Moog… and as for the TH VCOs they are great circuits. The blend let’s you get so many different tones out of the sub octave generator. It was a little tricky to build mind you, but after going through all the mods listed on Muffwiggler I got a nice stable unit in the end. I still have a spare board which I am gonna do in Kosmo at some point.
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Remember how i was having problems the other day… ya know… with a lack of power and such…
Well… turns out… its really smart to remove all of your 5v power cables from your main bus when you are done with your 5v project… lololololol
(Ribbon sits on 5v cv, gnd. for a 5v cable…)
So this explains why my VCO was doing nothing that afternoon… LOL
Changed the cable… boom. it works as intended… LOLOLOL
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So I just built my first oscillator module, and at the 4V test point I am measuring exactly 0.4V. Does this mean I accidentally used a resistor that is a wrong value, or is this because of something else?
Any advice about troubleshooting this would be great.
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Does the voltage not change when you turn the reference voltage trimpot
Yeah, you should adjust the RV3 trim until the test point says exactly 4.000 V (as close as you can get it). The LM4040AIZ 4.1 adjusts the voltage on the left side of the trim (in the schematics) to 4.096 V exactly, so the right spot is pretty close to that end.
If you cannot get close to 4 V, make sure you’re using a 4.1 or 5.0 V version of the LM4040.
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thanks! yes that would also be my first question!
after that. it would be which LM4040AIZ do you have? is it definitely the one with 4.1 after the numbers on it.
apart from that the best thing I would suggest is to double check the wire layout going to the rotary switch, maybe unplug that and see if that changes the voltage
next. check all solder joints, reflow and ones that look even a little bit suspect
if still no luck. download a resistor colour code app on your phone and just go through all of the resistors.
after that. well! lets see if we get there with the above first.
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