CD4017 ic 16step seq troubleshooting...need help  - Page 1
Forum section: electronics / beginners

author: rhesus3000
author_rank: Contributor
timestamp: April 10, 2017, 11:00:44 pm
content: Hello community!!Long story, short. I made a 16 step seq, usedtwo 4017ic's and aTLC555as 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 viaAND 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. Please help!!!here is a video so you can understand

author: Audioguru
author_rank: Super Contributor
timestamp: April 11, 2017, 12:30:58 am
content: Please attach your schematic showing the supply voltage and how the LEDs make the pulsing sounds.Some LEDs do not light and at least one LED that lights looks dim. Is that what you want?

author: Ian.M
author_rank: Super Contributor
timestamp: April 11, 2017, 01:00:45 am
content: One of the things to be aware of when you want to control an analog circuit from a digital output is that the logic level can vary slightly depending on what the other gates in the package are doing as they load the on-chip supply rails. When you show us the schematic, we'll be able to advise if that might be modulating your control voltage and maybe producing the unwanted echo effect.If you don't have a favourite schematic package yet, simply grab a sharp BB pencil, white paper and a ruler and give us a hand drawn schematic. Scanned is better than photographed, but if you haven't got a scanner, and you are careful with focus, lighting and to have the lens centered over the paper, you can get good enough results. HB and harder pencils often don't leave a clear line when photographed, and its a PITA having to go back over inking lines, or working in ink with all the problems that brings correcting mistakes, just to get a good enough image to share.

author: rhesus3000
author_rank: Contributor
timestamp: April 11, 2017, 08:00:35 am
content: Quote from: Audioguru on April 11, 2017, 12:30:58 amNo its not what i want...but i dont have a backup leds....sooi bypassed them. The supply voltage is a 9V battery.Quote from: Ian.M on April 11, 2017, 01:00:45 amThe AND gate is sn74hc11n...3 input Ic...was i right connecting it? Here are some images +schemMy 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.

author: tautech
author_rank: Super Contributor
timestamp: April 11, 2017, 08:10:49 am
content: You should have some bulk capacitance on the board, at least 100uFanddecoupling caps of 0.1uF across the supply pins of each IC.

author: rhesus3000
author_rank: Contributor
timestamp: April 11, 2017, 09:04:30 am
content: OOOOOWW!!! You mean i have to solder a CAP at each +v pin for all 3 IC's??? sorry for my english i dont understood "bulk caps" expresion.could you please explain me in a better way....sorry

author: Ian.M
author_rank: Super Contributor
timestamp: April 11, 2017, 10:33:11 am
content: 74HC.... logic is only rated for 5V operation (5.5V max). You *CANNOT* mix it with 4000 series logic running from a 9V supply. Its only safe to directly interconnect 4000 series and 74HC.... if they are BOTH running from the same supply of under 5.5V.

author: rhesus3000
author_rank: Contributor
timestamp: April 11, 2017, 10:53:05 am
content: NEW INFOOO!!!!i connected audio jack to only one step...and i get "double outout". WHAAAAAAA?? where am i wrong??here is a video.....

author: rhesus3000
author_rank: Contributor
timestamp: April 11, 2017, 10:54:32 am
content: Quote from: Ian.M on April 11, 2017, 10:33:11 amThank you i will correct that

author: rhesus3000
author_rank: Contributor
timestamp: April 11, 2017, 11:04:31 am
content: Ok..supply fixed...now all components are running at 4.5v! thank you for your advice! My mistake not reading datasheet.But the problem remains...

author: w2aew
author_rank: Super Contributor
timestamp: April 11, 2017, 01:05:01 pm
content: Quote from: rhesus3000 on April 11, 2017, 09:04:30 amIn a word - YES. Power supply filtering/decoupling is VERY important.Place at least 1 large electrolytic capacitor of approximately 100uF on your board.Then, place 1 ceramic capacitor of approximately 0.01uF at EACH of your ICs.Maybe this video I just made will help:

author: rhesus3000
author_rank: Contributor
timestamp: April 11, 2017, 03:10:37 pm
content: I did everything you taught us in your video. Still...the issue remains....i messed up with 555...thinking it had to do something...but nothing changed.

author: Zero999
author_rank: Super Contributor
timestamp: April 11, 2017, 03:50:42 pm
content: Quote from: Ian.M on April 11, 2017, 10:33:11 amTo be picky the 74HC series will work from 2V to 6V. I think you're thinking of the 74HCT series is 4.5V to 5.5V. Either way, you're right that the 74HC11 and CD4017 both need to be running on the same power supply between 3V and 6V.You should use a 5V regulator. A low drop-out regulator will give plenty of battery life from a 9V battery. You could try the LM78L05 but the output voltage will fall below 5V when there's still plenty of energy left in the battery. This may not be a problem, as the circuit will still work below 5V.See the following data sheets:LT1123http://cds.linear.com/docs/en/datasheet/1123fb.pdfMCP1702http://ww1.microchip.com/downloads/en/DeviceDoc/22008E.pdfLP2951http://www.ti.com/lit/ds/symlink/lp2951.pdfLM2931https://www.onsemi.com/pub/Collateral/LM2931-D.PDF

author: dentaku
author_rank: Frequent Contributor
timestamp: April 11, 2017, 11:13:42 pm
content: I see that's just a Baby 10 sequencer with an added AND gate so you can use 16 steps instead of 10 or less like the original Baby 10 uses. I breadboarded one a while ago with only 8 steps so it's much easier.http://hackaday.com/2016/01/14/oh-baby-baby10-build-a-classic-analog-music-sequencer/I would also suggest making sure you're using all 4000 series chips instead of mixing 7400 and 4000. This way you can use 9V or even 12V like most synth circuits use anyway.I don't know why you're getting two pulses but so far every thing I've been able to find about extending 4017 sequencers to more than 10 steps results in a gap between step 8 and 9 and even sometimes step one being half as long as the others.I simulated these three and they're all not perfect.This doesn't give a good sequence without a gap in the middle.http://electro-music.com/forum/phpbb-files/16_step_4017_247.pngThese two have the same problemhttp://electro-music.com/forum/phpbb-files/16_steps_109.jpghttp://electro-music.com/forum/phpbb-files/16_steps_354.jpgI just happen to have a 4514B (MC14514B) - CMOS 4-Bit Latch-4-to-16 Line Decoder which would work well as a 16 step sequencer. I could use a 4029 BCD-decade up/ down counter with it to make a sequencer with forward and reverse.

author: Audioguru
author_rank: Super Contributor
timestamp: April 12, 2017, 12:55:26 am
content: I asked you to attach a schematic but instead you show your wiring diagram which is completely different so we cannot compare it to the schematic in the datasheet of the CD4017.You have two gates in the high speed Cmos SN74HC11 floating which is bad, their inputs must be all at the supply voltage or all inputs must be at ground.The double sound output is probably one pop when an output goes high then a second pop when it goes low.

author: rhesus3000
author_rank: Contributor
timestamp: April 12, 2017, 06:56:18 am
content: Quote from: Audioguru on April 12, 2017, 12:55:26 amThat make sense i think! Sry about schem i dont have the software...did what i could.Quote from: dentaku on April 11, 2017, 11:13:42 pmGood info..i will use that in next seq. Thank you.

author: Damianos
author_rank: Frequent Contributor
timestamp: April 12, 2017, 09:05:42 pm
content: Something more to the previous comments:- What is the role of the two diodes in series with the power lines? Especially the one in the ground line. This maybe the reason of the "non zero" voltage that you measured (depending of where you connected the voltmeter). This also can "modulate" the signal across the entire circuit (where is connected the reference / "0 Volt" of the driving circuit?).- There is not a minimum resistance in series with the LEDs, it is just a potentiometer. It is possible that when activated an output, that is driving directly a LED, to produce "peculiar things" in the rest of the circuit.More when will be "published" a schematic with accurate information of what and how it is connected.Regards D.

author: rhesus3000
author_rank: Contributor
timestamp: April 12, 2017, 09:54:33 pm
content: Quote from: Damianos on April 12, 2017, 09:05:42 pmThe diods are there in order to block the 555 from other components supply and ground. I thought it would be usefull.The measurments i made are "after" the diod. If i measure "before" the diod i can hear the square wave produced by 555.I will test what you said about the leds...maybe i desolder them to see what happens to the circuit.I will try to make a schem.

author: Audioguru
author_rank: Super Contributor
timestamp: April 12, 2017, 10:37:34 pm
content: I use Microsoft Paint program to copy and paste a schematic from a datasheet or somewhere then change it to what my circuit is like. It is simple and quick.

author: rhesus3000
author_rank: Contributor
timestamp: April 13, 2017, 07:38:45 am
content: I finally got some time to create a schem....i hope i didnt miss anything...or made mistakes