# LMNC Simple VCO with Fine tune issue

**URL:** <https://lookmumnocomputer.discourse.group/t/lmnc-simple-vco-with-fine-tune-issue/3247>\
**Category:** DIY STUFF\
**Created:** [March 27, 2021, 4:09am UTC](https://lookmumnocomputer.discourse.group/t/lmnc-simple-vco-with-fine-tune-issue/3247 "2021-03-27T04:09:04Z")\
**Posts on this page:** 1\
**Showing post:** 11

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**Author:** ![fredrik](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/fredrik/32/682_2.png) [@fredrik](https://lookmumnocomputer.discourse.group/u/fredrik)\
**Post date:** [April 2, 2021, 5:48pm UTC](https://lookmumnocomputer.discourse.group/t/lmnc-simple-vco-with-fine-tune-issue/3247/11 "2021-04-02T17:48:23Z")

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> [@Dud](#):
>
> Sorry i don’t understand really what the Center note do.

Same as coarse tune in the stripboard layout, except that it’s a trimmer:

> [@Question about 3340 VCO module](https://lookmumnocomputer.discourse.group/t/question-about-3340-vco-module/506/27):
>
> Performance or DYI/stripboard? If the former, which trimpot are you tweaking – there’s the reference voltage trimmer (RV3) CTorp pointed you to (which is used by the octave selector and the fine tuning knob), but also coarse tuning/centre note (RV6), tracking (RV1), and high frequency adjustment (RV8) and they all do different things. Recommended order afaik is to trim RV3 with a multimeter, then use the octave selector and tuning trimmer (RV6) and knob (RV7) to dial in a mid note (datasheet s…

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