# Zorch's build progress

**URL:** <https://lookmumnocomputer.discourse.group/t/zorchs-build-progress/1553>\
**Category:** KOSMO MODULES\
**Created:** [August 5, 2020, 7:02pm UTC](https://lookmumnocomputer.discourse.group/t/zorchs-build-progress/1553 "2020-08-05T19:02:03Z")\
**Posts on this page:** 1\
**Showing post:** 2

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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:** [August 5, 2020, 7:34pm UTC](https://lookmumnocomputer.discourse.group/t/zorchs-build-progress/1553/2 "2020-08-05T19:34:44Z")

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So this is measured from the copper side, with a ±9 V supply? If so, the voltages look ok, except for the negative supply to the 3340 which is wrong – it’s connected to the negative rail via a resistor and should be held near −7.2 by a zener in the 3340. See:

> [@Annotated Simple 1V/Oct Oscillator Stripboard](https://lookmumnocomputer.discourse.group/t/annotated-simple-1v-oct-oscillator-stripboard/1267):
>
> And here’s [the LMNC 3340 stripboard layout](https://www.lookmumnocomputer.com/projects#/cem-3340-diy-simple), with scribbles: See [here](https://lookmumnocomputer.discourse.group/t/annotated-simple-low-pass-filter-stripboard/1266) for the annotated Simple Low Pass Filter stripboard.

What resistor are you using between pin 3 and the negative rail? For 9 V, the ideal value would be 200-220 ohm, so if you’re using 620 ohm you might simply be starving the circuit. Try soldering in a 330 ohm in parallel with the 620 ohm, or simply replace it with a 220 ohm resistor. (And don’t forget to remove/replace it if you decide to use 12 V instead).

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