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FIXED: Turing Machine not locking sequences
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3  Next [all]
Author FIXED: Turing Machine not locking sequences

flx

I recently bought a secondhand Turing Machine module and when I rotate the knob to its min or max position the sequences still change. It's especially noticeable when feeding the module a fast/audio-rate clock, in which case it changes the sequence about every second. Is that normal, or is there something wrong with the machine?


EDIT: I fixed it by soldering a 1M resistor in parallel to R31! Thanks for all the help!

roglok wrote:

EDIT: See this mentioned here: https://www.muffwiggler.com/forum/viewtopic.php?p=1011596#1011596



Alwaysnew

Try setting the length to the lower position and lock full CW on the mid knob. Erase all the marks by holding down the right switch and then add one mark to see if it stays like that.

This usually works for me.


flx

Alwaysnew wrote:
Try setting the length to the lower position and lock full CW on the mid knob. Erase all the marks by holding down the right switch and then add one mark to see if it stays like that.

This usually works for me.


Thanks. I tried that, and it still changed. sad banana Did the person who built it maybe use a pot with a wrong resistance?

EDIT: Checked the pot and it's labeled 50K, like it should be.


crossinger

flx wrote:

Thanks. I tried that, and it still changed. sad banana Did the person who built it maybe use a pot with a wrong resistance?

EDIT: Checked the pot and it's labeled 50K, like it should be.


Try it in the DIY subforum for Thonk's Turing kits. I'm not sure - but I think I recently read there about a similar problem (and its solution).

EDIT: I tried to set the link to the correct starting post (and the subsequent replies):

https://www.muffwiggler.com/forum/viewtopic.php?t=60740&postdays=0&pos torder=asc&start=923


negativspace

I'm pulling this from memory, forgive me if I'm misremembering, but I think the solution is to try different CD4015 ICs. This is why they're in sockets on the backside of the PCB (or should be.)


flx

Thanks for the link and the IC tip thumbs up I read some more in that thread, but I don't really know where to start troubleshooting. Patching the noise into another module doesn't help and I also tried providing the CV input with various voltages. I still couldn't get it to lock completely. I guess I'll order some ICs.

Also, the person that built the module, didn't solder the expansion pins cry which made adding the backpack and pulse module today quite a pain.


kwaidan

I found this info in Tom Whitwell's documentation:

Building the circuit
I’ve found the 4015 shift register chips to be slightly
unpredictable. If the sequence won’t loop properly,
swap the chip and throw out the old one. I’ve no idea
why this happens, but Navs reported the same thing
building his Bitsy. This is why the two 4015 chips are
on the back of the board, not hidden behind the
panel.
Quirks
Feeding the module from a multed clock input can
sometimes give strange results - clearing a looped
sequence. I’ve no idea why this happens.

You can find it on the Music Thing Modular website or through Thonk.


toby

Try clocking it from a different source. If the triggers are too long, like a square lfo, it can do odd stuff


Monobass

This should really be in the DIY forum. That comment about the 4015 was written before a lot of these kits were produced and in practice I've not really found that the 4015 or any of the ICs are the source of any build problems that have occured. When there are problems with locking its the white noise circuit that should be the first place to look for soldering problems, incorrectly installed components and bad joints etc.


flx

Thanks for the replies. I just checked the components and they seem to be installed correctly, according to the latest build instructions. I also don't see any visibly bad solder joints.

On a related topic, the Pulses module, which I built myself yesterday, puts out a trigger on step 8 as well, if step 7 triggers. So I get a double trigger from output 7. The LED only lights up once on step 7 though hmmm..... Maybe my Turing Machine is cursed?


Monobass

hi flx, the pulses module doesn't put out 'steps' from the sequencer, there are only 7 jacks so I'm not entirely sure what you mean, but for example there are definitely scenarios where the AND logic will result in several of the outputs sending triggers at the same time.


flx

Sorry, you're right, that wasn't phrased very clearly. The Pulses jack socket labeled "7" (the fourth one from above) sends two pulses after one another. The first pulse, when the RLS module has a 1-bit at position seven (which is the way it should be, as I understand it), and another pulse when there is a 1-bit at position eight. The second pulse doesn't light the LED next to socket "7" though.


windspirit

the ghost of turing, tune in next week for another scooby doo episode :p


roglok

I had the same problem. It all traced back to the gain of the noise transistor. The noise level created by my 2N3904 was too high. You can either try fiddling with the voltage divider or use a different transistor. I substituted a 2N222A, which fixed it for me.

EDIT: See this mentioned here: https://www.muffwiggler.com/forum/viewtopic.php?p=1011596#1011596


sammy123

I had the same problem. I removed the noise transistor and put in a socket. The first transistor I tried after that solved all my problems.



flx

Awesome! I will try those suggestions out smile


sammy123

I also reflowed all solder just to be sure...but it was the transistor.


flx

roglok wrote:

EDIT: See this mentioned here: https://www.muffwiggler.com/forum/viewtopic.php?p=1011596#1011596


SUCCESS! Soldering the 1M resistor in parallel with R31 fixed it! It's peanut butter jelly time! It's peanut butter jelly time! It's peanut butter jelly time!

Thanks so much for your help, guys!


The Pulses problem remains, but I might have narrowed it down to the expansion pins of the RLS module, which weren't put on the board by the person who built it cry So, I had to solder them from the "front" which might have connected some sockets underneath the display. I'm not really sure how to fix this, without desoldering the display ... but I'm not sure if I really want to do that.


Tombola

flx wrote:


EDIT: I fixed it by soldering a 1M resistor in parallel to R31! Thanks for all the help!



I'm so glad that worked! Seemed like a neat solution, but I hadn't tried it myself.


flx

Here's my expansion pin hack oops I assume doing it like that is fine, as it seems to work. I just soldered the pins to the lower row of display pins. w00t




The Pulses' "7" output still sends a second pulse when the eighth display position has a 1-bit, but I'm done with troubleshooting for today.


Again, thanks for all your help Rockin' Banana!


Monobass

Tombola wrote:
flx wrote:


EDIT: I fixed it by soldering a 1M resistor in parallel to R31! Thanks for all the help!



I'm so glad that worked! Seemed like a neat solution, but I hadn't tried it myself.


Yeah nice work smile


roglok

flx wrote:
roglok wrote:

EDIT: See this mentioned here: https://www.muffwiggler.com/forum/viewtopic.php?p=1011596#1011596


SUCCESS! Soldering the 1M resistor in parallel with R31 fixed it! It's peanut butter jelly time! It's peanut butter jelly time! It's peanut butter jelly time!

Thanks so much for your help, guys!


The Pulses problem remains, but I might have narrowed it down to the expansion pins of the RLS module, which weren't put on the board by the person who built it cry So, I had to solder them from the "front" which might have connected some sockets underneath the display. I'm not really sure how to fix this, without desoldering the display ... but I'm not sure if I really want to do that.


nice! parallel resistor didn't work for me, since i had some really nasty spikes going on...


sammy123

roglok wrote:
flx wrote:
roglok wrote:

EDIT: See this mentioned here: https://www.muffwiggler.com/forum/viewtopic.php?p=1011596#1011596


SUCCESS! Soldering the 1M resistor in parallel with R31 fixed it! It's peanut butter jelly time! It's peanut butter jelly time! It's peanut butter jelly time!

Thanks so much for your help, guys!


The Pulses problem remains, but I might have narrowed it down to the expansion pins of the RLS module, which weren't put on the board by the person who built it cry So, I had to solder them from the "front" which might have connected some sockets underneath the display. I'm not really sure how to fix this, without desoldering the display ... but I'm not sure if I really want to do that.


nice! parallel resistor didn't work for me, since i had some really nasty spikes going on...


Did a new transistor work for you?


roglok

sammy123 wrote:
roglok wrote:
flx wrote:
roglok wrote:

EDIT: See this mentioned here: https://www.muffwiggler.com/forum/viewtopic.php?p=1011596#1011596


SUCCESS! Soldering the 1M resistor in parallel with R31 fixed it! It's peanut butter jelly time! It's peanut butter jelly time! It's peanut butter jelly time!

Thanks so much for your help, guys!


The Pulses problem remains, but I might have narrowed it down to the expansion pins of the RLS module, which weren't put on the board by the person who built it cry So, I had to solder them from the "front" which might have connected some sockets underneath the display. I'm not really sure how to fix this, without desoldering the display ... but I'm not sure if I really want to do that.


nice! parallel resistor didn't work for me, since i had some really nasty spikes going on...


Did a new transistor work for you?


yep, see my earlier post. had to pick a different kind though...


joshuagoran

sammy123 wrote:
I had the same problem. I removed the noise transistor and put in a socket. The first transistor I tried after that solved all my problems.


@sammy123: Did you just try another 2N3904 and that worked? I am having this problem and the parallel 1M resistor solution didn't work and I have plenty of other 2N3904s.

Maybe they are low quality, I got mine from Tayda.

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