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CD4017 16step seq troubleshooting

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Rhesus3000

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Hello community!!
Long story, short. I made a 16 step seq, used two 4017 ic's and a TLC555 as clock. The two 4017 counter are cascaded as datasheet prompts to. My "touch" was that i used only "7" outputs including "0" (bad idea??) for the first 8 steps and output number "8" as a trigger to "activate" the second 4017 via AND gate. The second 4017 starts from output number "1" to "8" ("0" not used)...and "9"as reset to first 4017. And of course i included a diod for each output. So far so good? The result is, that my seq produces multiple steps at the same time i guess, more like a delay. Yes...it goes as it should, each step at a time without jumping and crewing it up (couple of burned leds)...but as soon i connect it to a CV input...i can hear this "echo" thing. I cant really explain what it does, but its not normal. I uploaded a video to show you

here is a video so you can understand


Supply Vol is 4.5V
The AND gate is sn74hc11n...3 input Ic...
I included bypass caps to components +bulk cap

Dont know if it is a problem anyway, but my multmeter shows that Voltage output of steps (one by one) measured before the diod...is never "0" when step "inactive"...it stays at 0.50~0.70V. (clue?) schm.jpg
 

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audioguru

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The diode at the Vss of the CD4017 ICs to "ground" is causing the outputs to never go to ground. Replace the diode with a piece of wire.
Aren't the LEDs very dim with the very low current output from the CD4017 ICs when their supply voltage is so low? In my LED chasers I use SN74HC4017 ICs with a 3V or 6V supplies for much more output current.
 

audioguru

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Does your "audio output" (from the diodes) have a resistance to ground maybe at the input of the amplifier?
 

Rhesus3000

New Member
No....i mean..there is one "wire" from aaaall 16 outputs (final stage) going to audio jack...and the jack is grounded. Is it thats what you saying?
 

audioguru

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I asked if the "audio output" of your circuit (the cathodes of all the diodes) has a resistance to ground which might be at the input of the audio amplifier. There will be no audio or very low audio if there is no resistance.
 

dr pepper

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I'm not really sure what yout issue is, however I notice the sequence doesnt count properly.
I think I'd have 1 4017 counting 0-9 all 10 steps, and the second 4017 having its 6th o/p to reset both counters, and use the logic gate to switch the clocks when its carry o/p is high.

Looks like an anfoss sequencer, very nice.
 

Rhesus3000

New Member
I asked if the "audio output" of your circuit (the cathodes of all the diodes) has a resistance to ground which might be at the input of the audio amplifier. There will be no audio or very low audio if there is no resistance.
when i touch the cathode of all diods output, with my finger, sound is getting louder and somehow clearer...so i need to solder a 1m ohm resistance to output(for example...or 10m ohm?)?
I'm not really sure what yout issue is, however I notice the sequence doesnt count properly.
I think I'd have 1 4017 counting 0-9 all 10 steps, and the second 4017 having its 6th o/p to reset both counters, and use the logic gate to switch the clocks when its carry o/p is high.

Looks like an anfoss sequencer, very nice.
I will do what you said...but its so painful at the moment.
 

dr pepper

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Yes it can be tricky when first starting, but stick with it.
It looks like you have the 220 ohm resistors for the Led's going to the wrong place, I'd expect those to go direct to the 4017 o/p's, you have them going to the analogue voltage o/p side of the 500k pots, thats going to affect your o/p voltage in a bad way, plus the leds will only light if the pots are cranked right up, and it wouldnt surprise me if this is causing your other issues.
Presumably the analogue output is going to a vco of somekind, your power supply being 4.5v plus the drop of the diodes will mean you'll only get 3.9v or so on the analogue o/p with the pot at max, if you need more then increase your supply voltage, more batteries.

Edit: Heres a 16 step 4017 sequencer, V1 is the clock source.
https://www.google.co.uk/search?q=4...i=3ob2WL-OGeiy6ATg-oCQDg#imgrc=MN506-C4dVzQ0M:
 
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audioguru

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In electronics, "m" is milli (thousandths) and M is mega (millions). 1m ohm is almost a short that is 0.001 ohm and 10m ohm is a little higher at 0.01 ohm. I think 1M or 10M is much too high.
The resistor to ground at the audio output should be about the same as the input impedance of the audio amplifier. Try 10k ohms.
 

Rhesus3000

New Member
Yes it can be tricky when first starting, but stick with it.
It looks like you have the 220 ohm resistors for the Led's going to the wrong place, I'd expect those to go direct to the 4017 o/p's, you have them going to the analogue voltage o/p side of the 500k pots, thats going to affect your o/p voltage in a bad way, plus the leds will only light if the pots are cranked right up, and it wouldnt surprise me if this is causing your other issues.
Presumably the analogue output is going to a vco of somekind, your power supply being 4.5v plus the drop of the diodes will mean you'll only get 3.9v or so on the analogue o/p with the pot at max, if you need more then increase your supply voltage, more batteries.

Edit: Heres a 16 step 4017 sequencer, V1 is the clock source.
https://www.google.co.uk/search?q=4017+16+channel+sequencer+circuit&tbm=isch&imgil=cyKk1JUZKsppJM%3A%3BuiT9A0giWmxUaM%3Bhttp%253A%252F%252Fwww.bowdenshobbycircuits.info%252Fpage5.htm&source=iu&pf=m&fir=cyKk1JUZKsppJM%3A%2CuiT9A0giWmxUaM%2C_&usg=__0yP0RgM2LQO47xSMLQQAX-OyVHg=&biw=1280&bih=889&dpr=1&ved=0ahUKEwi_9byb-67TAhVoGZoKHWA9AOIQyjcILg&ei=3ob2WL-OGeiy6ATg-oCQDg#imgrc=MN506-C4dVzQ0M:
Leds are connected to switch so that they wont light up when switch is off. Otherwise they woul light up no matter what...correct? I can see what you are saying about the 500k pots and the voltage ect..you are definitely right!!! ..but they arent the root of my problem...cuz in the second video i posted...i tested one output without pots switches diods ect. and still the problem remained. I cant give more power supply cuz the AND gate can handle up to 6V...and at the time i have no 6V power supply :p The feedback you gave is great btw...i take notes!!!!!

About the schem...i just thought the datasheet of 4017 would know better how to cascade them...so thats why i didnt copied other projects...i was a fool not including all outputs of first 4017
 

atferrari

Well-Known Member
The first video is what you would like to have?

The second one is not clear to me?

My first contact ever with digital IFs was precisely with the CD4017 using an analog multimeter. I got even stumped when I learnt that I needed a "clock" (!) for it to work.

What I learn in the very beginning was to test the strictly logic part and then adding LEDs, resistors et al. That would minimize your confusion.

Test logic first.
 

Rhesus3000

New Member
The first video is what you would like to have?

The second one is not clear to me?

My first contact ever with digital IFs was precisely with the CD4017 using an analog multimeter. I got even stumped when I learnt that I needed a "clock" (!) for it to work.

What I learn in the very beginning was to test the strictly logic part and then adding LEDs, resistors et al. That would minimize your confusion.

Test logic first.
Both videos are mine...and describe the problem. :p The second vid is just to show you how a single output sounds like...and it shouldnt be double :)
 

Rhesus3000

New Member
I did some measurements again. I measured the voltage of 4017 outputs straight from the IC. The supply is 4.5 V....my multimeter showed that in an instance (when output enabled) the voltage goes ~6V, and then drops to ~4.3V and then 0V when disabled. And something else...i am not sure...but i think each 4017 stage is opened for 2 clocks transition...and on the 3rd it moves forward. I drawed it so you can understand what i mean...dadadad.jpg
 

audioguru

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A single output makes a POP sound when the CD4017 output goes high, then it makes a second POP when the CD4017 output returns to low. If you want a single POP from each output then you could use a resistor and capacitor to slow down when an output returns to low.
 

audioguru

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Didn't you read the datasheet of the CD4017? It says that it advances one output when the clock pulse goes high.
Your circuit misses some counts and counts wrong because you did not connect it as shown in the datasheet.
 

dr pepper

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The increased voltage could just be stray inductance's in the circuit in conjunction with a sensitive meter.
And from memory the 4017 is edge triggered so it might look like there are 2 cycles, when in fact its 2 clock edges.
I suspect the double output thing is because your 4017's are not synchronized.
 

Rhesus3000

New Member
The increased voltage could just be stray inductance's in the circuit in conjunction with a sensitive meter.
And from memory the 4017 is edge triggered so it might look like there are 2 cycles, when in fact its 2 clock edges.
I suspect the double output thing is because your 4017's are not synchronized.
It makes sense thank you!! Now i need to "smooth" that second edge at high state of 555 i suppose ? correct?
I will try to sync them somehow...maybe push button from both ics end stage to reset or ground? maybe....

Didn't you read the datasheet of the CD4017? It says that it advances one output when the clock pulse goes high.
Your circuit misses some counts and counts wrong because you did not connect it as shown in the datasheet.
This is the first thing i have to correct. I will make another pcb this week. And inform the community about its progress.
 

Rhesus3000

New Member
A single output makes a POP sound when the CD4017 output goes high, then it makes a second POP when the CD4017 output returns to low. If you want a single POP from each output then you could use a resistor and capacitor to slow down when an output returns to low.
it would make it into a trianle wave somehow? my logic says....
 

audioguru

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It makes sense thank you!! Now i need to "smooth" that second edge at high state of 555 i suppose ? correct?
No. The POP sounds do not come from the 555. The sounds come from the outputs of the CD4017 ICs. I think you need beeps, not POPs.

Do you have an ordinary high current 555 that needs supply bypass capacitors that are not shown in your schematic? Or do you have a Cmos low current 555? If you have an ordinary 555 then its 400mA supply current draw each time it switches might be causing the supply to the CD4017 ICs to collapse and mess up the counting.
 
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