Hello everyone - I have a question about a circuit I’ve built and an issue I’m having with it. I have built a baby16 sequencer using the cascading schematic on the datasheet, with a 40106 as the clock source. The 40106 goes into a switch so I can start and stop the sequencer. I have also wired in a jack straight from the 40106 output pin (pin 2) to have a clock out as well so I can clock other things at the same time. My issue is that if I use that jack, the first step in the sequence is skipped. I don’t even have to plug it into anything, just having the jack engaged causes this to happen. I understand that everyone on here will likely want to see a schematic, which I don’t have exactly. I can draw one, but I’m wondering if this is an issue that is basic enough to not need it. Thanks for your help and I apologize for not providing a schematic up front. Please ask me any questions you have
Thanks again!!
Hello and welcome @tan, maybe add a push switch with a small reset circuit (pin 15 to + with a resistor to gnd ) can help you
Thank you @Dud - WIth this reset circuit, do you mean pressing ‘reset’ every time around the 16 steps, or with a latching switch I can just turn ‘on’? It skips this step every time.
A reset push button (momentary switch) will ground the reset and your pattern will start over. Its a useful performance option.
Not sure what this reset switch has got to do with the problem the poster has??
Response to an additional question. Answered for clarity as its unrelated.
Regarding the clk pin : is the jack grounding the pin in some way? How is the clk used in the data sheet?
The jack’s ground pin does go to ground, but there is no short between that pin and the signal pin. I’m not sure how to answer your second question exactly. The clock pin takes a clock signal in which is then used to step from one output to the next. If cascading these chips, the clock signal goes into the clock input of the first 4017, and then into an AND gate along with the final step +1 (Q8 in my case, or pin 9) which is connected to the clock inhibit pin, so that this pin stays high and the clock signal is sent to the clock input on the next 4017
The second question is more of a prompt. When a single pin behaves in an unexpected way I usually start with the data sheet examples to see what the original designers say should happen. And then I notice what I’ve done differently.
my proposition was for a reset switch to start the sequence at the begining when you push it.
but if it’s all time that it’s jump the step one, it’s maybe an error with schem or in the schem with the reset sequence step too, or other things
it’s not only the led who’s dead ?
have you your step 16 going to pin 15 (reset) with a diode ?
does it work with only 8 steps ?
i have made also a 16 step with 2 CD4017 , this is the schem i use
(it’s for more step but i use only for 16 step : first and last stage)
i don’t know if that can help you ?
Thanks everyone for your input - I want to clarify that the circuit works just fine as it is: all LEDs light, any number of steps I give it to cycle through works, etc. The issue I am having is that I have the clock signal ALSO routed to 1/4" jack to send the clock out while using this sequencer. When I engage this jack, the circuit skips the first step, even without plugging it into something else. @Dud - I also am using that same schematic for mine. I am wondering if I need to buffer the clock signal before it goes to the jack possibly?
Thanks again everyone!
Yes, you probably should buffer the clock.
What may be happening here is that the cable adds enough capacitive or inductive load to stretch the clock or cause it to ring so that the first 4017 sees a clock immediately after being reset so it immediately moves away from step 0 (it can’t really skip it completely).