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altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
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Posted: Tue Feb 11, 2014 6:03 pm Post subject:
4017 Sequencer build Subject description: Need another set of eyes on this to troubleshoot |
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No schematic but nothing too tricky, just a 555-clocked 4017 to 4046 oscillator. My only customization being that the unit can send and receive clock signals, a low pass cap switch, a pseudo-glide switch which inserts a 2.2up cap across the max high and max low resistors on the 4046 which I thought sounded cool and a switch after the diodes on the tuning pots that can send the CV out to a patch jack, to the 4046 VCO IN (pin9), or OFF.
Got a seven-step version on breadboard (sans toggles and jacks). Drew the layout up and fired up the iron.
Surprise!...not working right. Clock works, bulbs chase and nothing but a straight tone at audio jack, Low Pass works, Glide comes on and the pitch of the note shifts up, pots do not sweep the freqs as they should (note actually goes slightly lower when fully clockwise).
Anybody out there see any first-glance bad stuff here? I've been going from breadboard to drawing to circuit visually and with a meter as much as possible (not that I'm terribly clever with a meter or anything). Soldering is decent. I'm terribly frustrated here and don't know where else to go! HALP!
The images are posting in reverse order i think. Sorry.
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red in from 4017 out wiper through diode to DPDT toggle (Gate Out, OFF, 4069 VCO in) |
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Had to make some connector choices with what I had |
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Had a brain fart putting the headers in by the 4017. The pin off of pin 9 on the flipped 4017 is the common for step selector switch |
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_________________ Noise is for heroes! Last edited by altern8 on Tue Feb 11, 2014 9:55 pm; edited 2 times in total |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
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altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
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Posted: Tue Feb 11, 2014 6:33 pm Post subject:
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Ahem...uh ...it is. Both of em, breadboard and soldered.
Don't know why I was typing "4069"
. _________________ Noise is for heroes! |
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altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
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Posted: Tue Feb 11, 2014 10:02 pm Post subject:
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Revised circuit layout to reflect use of 4046. Seriously am I overlooking something here? Again, breadboard works perfectly. Spent three days designing the enclosure and putting this together and I'm totally at a loss as to why it's behaving this way. Completely dispirited at this point. _________________ Noise is for heroes! |
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commathe
Joined: Jul 26, 2013 Posts: 153 Location: Beijing
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Posted: Wed Feb 12, 2014 12:12 am Post subject:
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I can't see anything immediately wrong, but my general debug procedure is to go "backwards" from the problem. Your problem seems to be that the steps are not actually changing the pitch of the oscillator, but that everything else is acting as it should (or at least appears to be). If you still have it on the breadboard then try and do some multimeter comparison.
The only thing you appear to have introduced are the toggle switches, right? Maybe those diodes are doing something you didn't expect them too.
Sorry I can't be of more assistance. I don't really understand how this circuit sequences. I am not great with sequencers and I rely heavily on multiplexers to do all the work! All I see here is a "preset selector" with a big rotary switch to choose between 12 knobs.
Can you provide a schematic? More of a rundown of what the circuit does? |
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DUBmatze
Joined: Feb 18, 2013 Posts: 150 Location: south Germaica (schwabilon)
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DUBmatze
Joined: Feb 18, 2013 Posts: 150 Location: south Germaica (schwabilon)
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Posted: Wed Feb 12, 2014 4:53 am Post subject:
Re: 4017 Sequencer build Subject description: Need another set of eyes on this to troubleshoot |
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... ahhh
altern8 wrote: | a pseudo-glide switch which inserts a 2.2up cap across the max high and max low resistors on the 4046 |
DUBmatze wrote: | you conectet the cv out of the 4046 (pin 10) to the R pin 12. is there anything comming out of the 4046s pin 10 when nothing is connected to 3 or 14? |
you connect 10 and 12 with cap and switch
-> 11 -||- 12 ? |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
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Posted: Wed Feb 12, 2014 8:07 am Post subject:
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Nice image DUBmatze, would look good on a T-shirt
from what I can decode the gate out isn't really a standard gate with a fixed voltage but the amplitude can be varied with the potentiometers.
Not sure if that is on purpose or a mistake and it might need a pulldown resistor depending on what you attach it too.
"this is the gate ?" that point is connected to the individual outputs of the 4017 and also goes to the step select switch.
"this is just V+ ?" those point are all connected together on the PCB and provide the CV for the 4046 VCO.
"not soldered" I dunno, probably is, was that a question ?
Besides the gate outputs I don't directly see a reason why it shouldn't function. Does the CV vary when it goes through the steps ? Since you're
using connectors you could try if the frequency changes by just controlling the CV input directly with a potentiometer connected between + and GND.
on a side note: you only need 1 resistor for all 10 LED's, since only 1 output is high at a time. Not that's it's bad to use 10 resistors but you could
connect the LED's directly to the switches, and solder the cathodes together with a resistor to ground. That'll save you some wiring. _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
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DUBmatze
Joined: Feb 18, 2013 Posts: 150 Location: south Germaica (schwabilon)
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
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altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
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Posted: Wed Feb 12, 2014 10:14 am Post subject:
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Thanks for the responses. Yeah my "Gate Out" jacks would be effected by the pots. Thanks for the pull down resistor tip on those outputs.
Below are some attachments that might clarify a couple things.
Biggest problem I'm having is that the pots are not changing the pitches on their respective steps, but only on my soldered version.
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This is the basic block diagram this is based on. The only major difference is I'm using a 555 to clock. I'll draw up a proper complete schematic later today. |
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This clarifies how the pot/diode, SPDT assembly connects to board through the three pin connector. I was intending for the second pin to connect to ground but then figured out I can run the ground across the pots where it finally connects to the board at |
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_________________ Noise is for heroes! |
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noto
Joined: Nov 05, 2009 Posts: 24 Location: portland
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Posted: Wed Feb 12, 2014 1:57 pm Post subject:
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so the VCO is producing a sound but the CV bus doesn't change the pitch? if everything in the sequencer section works, i would start by running the sequencer, pausing it, then measuring the CV bus while rotating the respective steps' potentiometer. if the voltage doesn't change, maybe the diodes are wired backwards... if the voltage does change like it should, i would try disconnecting the CV bus from the 4046, and test the input with a voltage divider CV input to determine if the VCO is wired up correctly.
i am not too familiar with 4046, but it seems like if you can get the VCO to change pitch with a CV, and the sequencer is putting out what it should, the circuits should work together. maybe the 4046 is toast... |
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altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
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altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
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Posted: Tue Feb 18, 2014 2:56 pm Post subject:
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haven't fully looked at it but immediately noticed that you have the RST
and CLKINH pins floating (when no switch is pressed). Add some pulldown
resistors to these pins, say 100K. (if I spot something else I'll let you know).
edit:
hmm I don't see anything else that could cause problems but I think you
made an error in the schematic around the glide capacitor. Right now
everything is connected to GND. Also the 4017 needs a fairly high level CLK
signal. So if you would power it from 12V and then use a 555 to CLK it
powered from 9V it might not work. (would have to check the datasheet to
see what the min voltage level is for a high signal). _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
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altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
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altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
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Posted: Tue Feb 18, 2014 7:58 pm Post subject:
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PHOBoS wrote: | :
...the 4017 needs a fairly high level CLK
signal. So if you would power it from 12V and then use a 555 to CLK it
powered from 9V it might not work. |
I found that glide cap issue. The newer schematic should show the correction.
As far as the voltage issue with running two or more of these I see your point but something has fritzed in the build since I tried to test the external clock signal feature. Now, even standing alone without trying to clock externally -- it demonstrates the symptoms I've outlined above.
I'm wondering if a momentary live connection toasted the 555 or the 4017. Say if both the 555 chips were high at the time of connection and a situation happened while inserting the external jack -- what could that do? Sorry to be such an electrical engineering doofus. I'm sure there are a lot of us lately.
Getting into the box means basically disconnecting everything, making the change and putting it all back together. I built it with connectors but a lot can go wrong with all the handling and I've handled it a lot! Hoping for some insight before I dig in again! _________________ Noise is for heroes! |
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altern8
Joined: May 25, 2012 Posts: 30 Location: Alabama
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Posted: Sat Feb 22, 2014 6:25 pm Post subject:
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It turned out to be a jack issue, but I think Phobos is probably right about not being able to drive more than one 4017 with 9 volts. Guess I'll be learning to get more out of datasheets! _________________ Noise is for heroes! |
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micyclebicycle
Joined: Jun 06, 2013 Posts: 8 Location: USA
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Posted: Sun Mar 09, 2014 4:20 pm Post subject:
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In your schematic the reset button is between the output of the rotary switchand the IC, so the signal from the last step probably wont make it to the reset pin.
Dont know if this is the source of your problem, Good Luck! |
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