We have a thread for things like that 
You probably fried the TL074, but with a little luck everything else still works:
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ah yeah. sorry, sometimes I canât sleep at night for my choice of using the same connectors for the oscillator driver and the power!!! I promise it came from a good place the idea haha, the idea being it just means you probably already have a connector around for that socket as its the same as all of the powers saved people having to buy a different thing, but yeah I admit I have done it a couple of times too. human error hopefully its just the opamp!!!.
the long overdue drive is pretty much done now, drums next within the next week! keyboard sequencer then the driver, and I figure when that it in the modular too itâll be harder to plug in the power wrong as that will be already connected to the driver socket.
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GladI never fitted the link as I would probably have a dead VCO by now 
Easy fix. Add (1) 2x5 cable connector to the BOM. On assembly plug the connector into the link header as a plug so you wonât accidently connect power to it.
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As long as you donât accidentally plug the plug into the power header and then plug the power cable into the link header
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At least this way you only have to be extra careful once and itâs out on the workbench instead of feeling behind the module in the rack.
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Can anyone in the USA tell me where you purchased your rotary switch ? I canât seem to find the Alpha switch from the BOM.
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I bookmarked some which looked like the ones Sam used. I believe the Tayda switch and the Mouser switch is only different by the solder lugs or the PCB pins.
https://www.mouser.com/ProductDetail/Alpha-Taiwan/SR2612F-0112-21R0B-D8-N
-Fumu / Esopus
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Hey guys, just put my VCO together and they were working just fine for a while but now my saw output doesnt work and the TL074 is getting real hot whenever i plug it in. This happened after i did the little fix where you put a 10M resistor on pins 4 and 5 of the 3340 but even after I took it off its still happening. All my chips are in the right way too I made sure to check.
EDIT: The tuner display also is not showing anything, the arduino is fine and runs the LED test but just goes blank after. This is happening to 2 of my 3 VCOs. One still has the 10M one doesnât. (the other vco is doing nothing so far)
A 10M resistor wonât pass enough current to heat anything up, so odds are youâve accidentally introduced a solder bridge or other short while tinkering with the new resistor. Check your solder joints.
I scrolled up just a bit, found exactly what happened. Plug power into the link port and fried my TL074. Good thing I have a couple extras.
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Alright now im having an even weirder issue, one is perfectly fine but the other changes pitch like crazy whenever I move it. Sounds like a mosquito going crazy
Tested that its none of my 3340s they all work fine. Whenever i touch C6 the pitch goes crazy, much more than when i do that on the one that works. i dont see any touching joints either
I donât know if you do it, but test to look with a magnifying glass or a multimeter, sometimes itâs invisible to the eye
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After too many hours I figured it out, even though i retouched every joint, one joint on the +6 -6 pot had something wrong with it where if it moved a certain way it messed up the pitch.
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Hey guys, put most the case âtogetherâ for a little test today and when i plugged my beatstep into the 1222 CV and tried to play different notes, each note barely changed the pitch at all. Not sure what to do, had all the pots calibrated right
thats a weird one! sorry for the obvious questions!! definitely in the right hole on the beat step? st to 1v/oct on the Arturia midi centre program? does plugging in anything else to the 1222 do anything similar??? I guess figuring if the problem is the 1222 end or the beat step end is the best way of figuring it out
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