# Help needed for UNVERIFIED AS3340 VCO Stripboard Layout (No Arduino/Display) **URL:** \ **Category:** DIY STUFF\ **Created:** [January 16, 2021, 7:43pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707 "2021-01-16T19:43:06Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 16, 2021, 7:43pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/1 "2021-01-16T19:43:06Z")
I’m in the process of building my first module using schematics from the performance VCO and AS3340 data sheet. I’m uploading my (messy) stripboard layout here before I build just as a check for me to see if someone spots a glaringly obvious error and if all goes well, I’ll make an edit to this post giving the all clear for anyone’s future use! ![as3340vco.v2](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/8/814c78b58e5330d5d455b877ab782297444a60c6.png) UNTESTED ---
**Author:** ![Caustic](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/caustic/32/15588_2.png) [@Caustic](https://lookmumnocomputer.discourse.group/u/Caustic)\ **Post date:** [January 16, 2021, 8:27pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/2 "2021-01-16T20:27:46Z")
Is this tested and known to work? ---
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 16, 2021, 9:05pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/3 "2021-01-16T21:05:40Z")
I was posting to see if anyone could spot any glaring mistakes. I will edit the post and add a comment when it is fully tested 🙂 ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [January 16, 2021, 10:17pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/4 "2021-01-16T22:17:15Z")
it’s better to write “Untested” on your stripboard layout because we can find this image by doing a search without necessarily reading that it is not tested yet, thx ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [January 16, 2021, 10:55pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/5 "2021-01-16T22:55:07Z")
maybe add the 10M resistor between pin 4 & 5 look here for some info even if it’s for the 1222 VCO schematic > [@1222 Tuner VCO Module fixes/improvements](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module-fixes-improvements/2072): > > These informations are all over the place, so let’s summarise them here. “Mandatory Fix” (even if your module seems to work): replace R42 (220R) with a resistor between 1K and 4K7. With 220R the LM4040 is way out of its maximum rating and causes wobbling of the pitch, or it could just be destroyed. [Look here](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/203) Easy (no excuses to not do them if you build a new 1222): replace the L7805 with a L7808 because the Arduino is powered thru Vin not +5V. add a resistor between pins 4&5 of the 3340 … ---
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 16, 2021, 10:56pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/6 "2021-01-16T22:56:01Z")
Yeah! I was just reading that thread and that’s definitely something I’ll add. ---
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 25, 2021, 4:32am UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/7 "2021-01-25T04:32:50Z")
![as3340vco.v2.20210120-170507.20210121-225453](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/3/353bc9782829a012f181bcbfb4e923d893d47f26.png) I am getting most of everything to work so far, however, the square wave output is not working. I have checked bridging and continuity and all seems good. In addition (obviously), I am not able to test the PWM and PW functions due to this. I won’t take pictures of my mess of wires that is my board because troubleshooting that way would be near impossible from an outside perspective. Does anyone notice any errors in terms of the square wave stripboard layout? ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [January 25, 2021, 9:45am UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/8 "2021-01-25T09:45:40Z")
difficult layout for me, but pin 3 of TL072 it’s missing a 10K resistor to GND 😉 a little advice when it’s full like that I put resistors on the potentiometer, rotary switch … ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [January 25, 2021, 1:18pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/9 "2021-01-25T13:18:56Z")
For instance you can do something like this with a rotary switch, saving not only space on the board but three of the wires: ![rotswitch](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/7/7fffb1757b5f1ee20e555404d37b1657e1d21d98.jpeg) ---
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 25, 2021, 6:31pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/10 "2021-01-25T18:31:51Z")
I didn’t see that 10k resistor in the performance VCO schematic, however, I did see it in the 1v/oct simple VCO. Also, I noticed the 470k and 100k resistor values are switched between the two layouts. ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [January 25, 2021, 6:47pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/11 "2021-01-25T18:47:42Z")
> [@laminar](#): > > I didn’t see that 10k resistor in the performance VCO schematic R9 : ![schematic](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/9/9317032b130993aa439ee55d4f66bd7dd0d24f62.jpeg) for mine i replic the simple version and add all the others things after (octave, sync H&S, …) ---
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 25, 2021, 6:49pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/12 "2021-01-25T18:49:45Z")
Ahh, I had that attached to pin 4 of the AS3340 directly. I don’t think that should be an issue? ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [January 25, 2021, 10:11pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/13 "2021-01-25T22:11:11Z")
this resistance is necessary, it is in all versions. R9 = 10K for CEM3340 and 51K is recommended for AS3340. There are 2 connections to pin 3 of TL072. - pin 3 wire to pin 4 of AS3340 (like you do) - and pin 3 resistance from 51K to GND forward if your square works ---
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 25, 2021, 10:38pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/14 "2021-01-25T22:38:08Z")
I moved R9 from pin 4 of the AS3340 (to ground) to pin 3 of TL072 (to ground) and it’s still not producing anything. ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [January 25, 2021, 10:43pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/15 "2021-01-25T22:43:18Z")
no, R9 (a resistor of 51K) start to pin 3 of the TL072 and go to GND ![schematic](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/9/9317032b130993aa439ee55d4f66bd7dd0d24f62.jpeg) “VP” it’s the AS3340 pin 4 so 2 connections from pin 3 of the TL072 ---
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 25, 2021, 11:04pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/16 "2021-01-25T23:04:53Z")
I think there’s a miscommunication. I have a wire from pin 4 of the AS3340 to pin 3 of the TL072. Now, I also have R9 going from pin 3 of the TL072 to ground (where I moved it from its original position from pin 4 on the AS3340 in the stripboard layout). Therefore, two connections from pin 3 of the TL072. ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [January 25, 2021, 11:13pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/17 "2021-01-25T23:13:36Z")
> [@laminar](#): > > I think there’s a miscommunication sorry for that 🙂 if it doesn’t work there must be something else have you turn the PWM during your square test, PWM work with Squre wave and it has dead point = without any sound ---
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 25, 2021, 11:17pm UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/18 "2021-01-25T23:17:41Z")
No worries! Yes, I have turned both PWM and PW pots while testing. ---
**Author:** ![laminar](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/laminar/32/19664_2.png) [@laminar](https://lookmumnocomputer.discourse.group/u/laminar)\ **Post date:** [January 26, 2021, 5:43am UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/19 "2021-01-26T05:43:24Z")
Comparing the square wave part of my layout (which, again, follows the performance VCO schematic) to the 1v/oct simple VCO w square wave layout, I have come across a few key differences: - Sam’s layout has a 10k resistor coming off pin 4 of the CEM3340 to ground, as well as another 10k coming off pin 3 (IN+) of the TL072 to ground. Whereas mine only has the latter (where the 10k is changed to 47k for the AS3340). - He sets a 470k from pin 5 of the CEM3340 to pin 7 (OUT) of the TL072 for PW where mine does not include that at all (following the performance VCO schematic). - He connects pin 6 (IN-) to pin 7 (OUT) of the TL072 directly where mine utilizes the 100k resistor in between. - He uses a 100k resistor instead of a 470k (from the schematic) from pin 5 (IN+) of the TL072 to the central lug on the PW pot. - The 10M resistor that was suggested to be added between pins 4 and 5 of the AS3340 does not occur on either schematic or Sam’s layout which was implemented in mine. Those are the key differences which were not initially implemented as my assumption is that a bit more experience went into the schematic of the performance VCO rather than his initial simple VCO (therefore changing it up). If any of these points sound suspicious to you, please let me know! ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [January 26, 2021, 10:11am UTC](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707/20 "2021-01-26T10:11:04Z")
sorry i don’t know, maybe this thread can help you > [@Advice for troubleshooting 3340 based VCO](https://lookmumnocomputer.discourse.group/t/advice-for-troubleshooting-3340-based-vco/2077): > > This is a wiki post; please correct and improve! This is written regarding the 1222 Performance Oscillator module, but similar things apply to the simple stripboard oscillator or other oscillators based on the 3340 chip. For the stripboard version also see If you are not getting good tones from the oscillator, do the following. If with the 1222 you are also not getting good behavior from the tuner, don’t waste time on trying to fix that yet. Get good tones on the outputs first — the tuner won… [Next page](https://lookmumnocomputer.discourse.group/t/help-needed-for-unverified-as3340-vco-stripboard-layout-no-arduino-display/2707.md?page=2)