[BUILD] Bytes Turing Machine expander

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elcoco
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Post by elcoco » Sun Apr 10, 2016 5:10 pm

The output from volts goes all the way to 0 but the seq output on the turing machine only goes down a bit but it makes for a perceptible change in pitch.

** EDIT: Fixed it, I had connected the cables incorrectly.

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Post by windspirit » Mon Apr 11, 2016 2:04 am

Glad to hear it

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Cut both traces on Turing Board

Post by saduJ » Sat Jun 11, 2016 10:32 pm

Yep--- when doing the steps to install the Bytes expansion, I cut both traces by mistake when taking XACTO to my beautiful, functioning Turing Machine. :doh: Anyone know where I should tie in the incorrectly cut trace?

Thanks!

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windspirit
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Post by windspirit » Sat Jun 11, 2016 10:43 pm

Go from the middle pin of the length switch to pin 1 of the CD4016. If you like I can make a picture but it will take me a little longer.

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Post by saduJ » Wed Jun 15, 2016 2:42 pm

Go from the middle pin of the length switch to pin 1 of the CD4016. If you like I can make a picture but it will take me a little longer.
Thanks for this, it solved my problem with the trace cut. As for my other troubleshooting experience, in case anyone else runs into this:

I was experiencing the "fill the buffer once and then empty" behavior on the long-length side (re-purposed Turing Machine "length" switch up so Bytes knob 9-16 is in control) as others had, but the 1-8 (Turing Machine length switch down) knob was giving me proper divisions. It occurred to me to switch the two 4051 chips with each other, and sure enough, the long-length knob started to work and the short-length knob had no effect. I bought two new 4051s and now my Bytes functions properly.

Thanks to everyone on here who posted before for the help. This morning, I had my first jam with odd time signatures over a 4/4 beat and the Turing Machine with Bytes is SO MUCH FUN!

:sb:

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nevetsokyeron
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Re: Trace cut not necessary

Post by nevetsokyeron » Tue Jul 19, 2016 12:58 am

windspirit wrote:
CeeJay wrote:I figured out that a trace cut on the Turing Machine PCB is not necessary for a working Bytes expander. Instead you can remove (desolder or just clip off) the resistor R14. I think that is easier to do and there is no need to damage the board.
Wow I think you are right! I am going to verify this and possibly update the build documents to reflect them. Send me your address and I will send you some goodies in appreciation :cloud: .
Did this ever get added to the documentation? I did not see it the first time through.

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windspirit
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Post by windspirit » Tue Jul 19, 2016 1:48 pm

Nope, my plgate has been pretty full with getting the other modules out. I am in the process of migrating everything to github and I want to update documents in the process.

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Post by nevetsokyeron » Wed Jul 20, 2016 4:13 pm

windspirit wrote:Nope, my plgate has been pretty full with getting the other modules out. I am in the process of migrating everything to github and I want to update documents in the process.
Cool. Thanks. Having the stuff on Github should be nice. I look forward to it.

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Post by coolshirtdotjpg » Fri Jul 22, 2016 4:45 am

Does anyone know if you can sub in 50k pots for the the 100k, mouser is only allowing orders of 1000, and I have plenty 50k pots lying around.
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Post by windspirit » Fri Jul 22, 2016 1:07 pm

If you are in the US then smallbear and erthenvar also carry those jacks and have quick delivery. Using a smaller pot can affect the distribution of the mumbers along the travel of the pot.

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Post by coolshirtdotjpg » Fri Jul 22, 2016 6:09 pm

windspirit wrote:If you are in the US then smallbear and erthenvar also carry those jacks and have quick delivery. Using a smaller pot can affect the distribution of the mumbers along the travel of the pot.
Thank you so much.
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Post by coolshirtdotjpg » Tue Aug 02, 2016 6:05 pm

I am very confused. I can't find a way to determine the values of the resistors in any of the build documents. Is there a schematic somewhere? The bom doesn't show what resistor values correlate to the which number resistors on the PCB. I must have missed something, can someone help me out? Thanks! (correction, this is an issue with a third party PCB not having the values on it, but any insight would be helpful, thanks!)
Last edited by coolshirtdotjpg on Tue Aug 02, 2016 6:19 pm, edited 1 time in total.
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Post by nevetsokyeron » Tue Aug 02, 2016 6:19 pm

coolshirtdotjpg wrote:I am very confused. I can't find a way to determine the values of the resistors in any of the build documents. Is there a schematic somewhere? The bom doesn't show what resistor values correlate to the which number resistors on the PCB. I must have missed something, can someone help me out? Thanks!
Are you using the Thonk build docs? They list parts and assembly order.
https://thonk.co.uk/documents/Turing/
https://thonk.co.uk/documents/turing2016/

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Post by coolshirtdotjpg » Tue Aug 02, 2016 6:38 pm

nevetsokyeron wrote:
coolshirtdotjpg wrote:I am very confused. I can't find a way to determine the values of the resistors in any of the build documents. Is there a schematic somewhere? The bom doesn't show what resistor values correlate to the which number resistors on the PCB. I must have missed something, can someone help me out? Thanks!
Are you using the Thonk build docs? They list parts and assembly order.
https://thonk.co.uk/documents/Turing/
https://thonk.co.uk/documents/turing2016/
Thank you, but those do not include Bytes.

Actually, it looks like the only one I couldn't find on the image of the PCB is R4.
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Post by windspirit » Tue Aug 02, 2016 11:20 pm

The eagle files are available on my website and you can see the values there. There should be a link in the OP.

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ambrohski
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Post by ambrohski » Tue Aug 02, 2016 11:35 pm

In search of a PCB for this wonderful expander, but only finding PCB/panel combo available- does anyone know where I might find just the PCB? :despair:

Thanks!

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Post by coolshirtdotjpg » Wed Aug 03, 2016 12:27 am

ambrohski wrote:In search of a PCB for this wonderful expander, but only finding PCB/panel combo available- does anyone know where I might find just the PCB? :despair:

Thanks!
You can get one from magpie modular
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Post by coolshirtdotjpg » Wed Aug 03, 2016 12:28 am

windspirit wrote:The eagle files are available on my website and you can see the values there. There should be a link in the OP.
Sounds good. I don't have eagle, but maybe there's a viewer?
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Post by ambrohski » Wed Aug 03, 2016 1:22 am

coolshirtdotjpg wrote:
ambrohski wrote:know where I might find just the PCB? :despair:

Thanks!
You can get one from magpie modular
Got it, thanks- but I didn't get outta the store without :moneyburn: on other stuff too :hihi:

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Post by windspirit » Wed Aug 03, 2016 3:55 am

coolshirtdotjpg wrote:
windspirit wrote:The eagle files are available on my website and you can see the values there. There should be a link in the OP.
Sounds good. I don't have eagle, but maybe there's a viewer?
Oh yeah just look up gerber viewer (i use gerbv on linux) although eagle is free and pretty easy to look at the boards with.

@ambrohski sorry I saw your message but forgot to reply. Ill probably do one last small run of these soon for people who still have v1 turings at which point I may have some extra boards. If you dont want to wait go with magpie.

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Post by nevetsokyeron » Sun Aug 14, 2016 3:46 am

I finished my build tonight and it went pretty well I think. Still have to do some proper testing.

Question:

If I cut the trace on the main sequencer board - where can I check for continuity to see if the trace is really cut or not?

(Of course I re-read this thread afterwards and see the thing about removing R14 instead of the trace cut)

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Post by nevetsokyeron » Sun Aug 14, 2016 3:54 am

coolshirtdotjpg wrote:
Thank you, but those do not include Bytes.

Actually, it looks like the only one I couldn't find on the image of the PCB is R4.
I did my build tonight and realized what you were asking here. Yeah - there's no list of the parts and the corresponding board placement (R1 = 470ohms, etc). The PCB I got from Magpie does not list the resistor values on the board.

I ended up loading up the schematic and made a list.

470K = R1, R2, R6, R7, R8, R10, R11, R16, R18, R19
2.2K = R3, R4, R5, R12, R13
100K = R14, R15

WHY IS THERE NO R17?

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Post by atari5200 » Tue Aug 23, 2016 2:11 pm

windspirit wrote:
Zaibach wrote:So, after a while I decided to calibrate the trimpot of CV input of the Bytes expander. But I discovered that it doesn't react to incoming CV! I tried the given calibration method (clocked at audio rate, saw LFO at CV input, change knob fully CCW, pattern lenght to minimum, CV attenuverter fully CW), but nothing happens. I measured the voltage coming from the wiper of the trimpot, making sure that it doesn't attenuate the CV completely, but i get +/-4V! I exchanged the TL074 just to be sure and reflowed all solder joints - but I can't modulate the pattern lenght with CV. Everything else works like it should - modulating the pattern manually via the pots and the switch. Any ideas where to look next? It's not vital for what I do - it's just bugging me and against my DIY pride that I have a module in my rack that I screwed up somehow...
I know what that feels like!

Do you have an oscilloscope? That will make things easier for you. If not you can run the following tests with a DC voltage and it should work with a voltmeter

Start with your CV attenuverter knob at 12 oclock, CV switch in the middle position.

Test the voltage at pin 1 of your ADC0820, the top ADC corresponds to the short length knob and the bottom ADC corresponds to the long length knob. It should go smoothly between 0 and 9 volts as you go through the entire range of each length knob.

Now apply either a voltage or an LFO to your CV input, turn the CV attenuverter clockwise, and see if there is any difference. You should either see an LFO or a DC voltage added to the offset provided by each length knob. If not, test pin 7 of the TL074 and see if the voltage there corresponds to the CV being applied at your input. If not, test pin 1 of the TL074 and check for the same thing. If you have no luck with any of that let me know and we will go from there.
So I'm having a similar issue in that my CV input isn't doing what I'm expecting it to but it could be that I'm also misunderstanding what it should be doing!

When I feed a +5V DC voltage into the CV in and turn the CV attenuverter all the way up I can measure this voltage at the attenuverter wiper pot, the 100k trimmer wiper pot, pin 1 of the TL074 and then pin 7 of the TL074, but when it hits pin 1 of the ADC0820 it's been pulled down to 2.3V, so I can't get a full sweep of the lengths, in the short position it sweeps from 1-2 or 3 and that's about it.

If I don't use CV, I can sweep through the full range using the knobs so that part is working properly. The trimmer is allowing all the voltage through so I know that's not the choke point either. Is this normal? Do I just need a larger voltage sweep to hit the full range of positions or is this indicating some other issue?

EDIT- I tried it with other voltages and the result is the same, I measure the proper voltage at the points mentioned above but when it hits pin 1 of either ADC0820 based on the position of the switch it's always slightly less than 1/2 of what goes in...
Last edited by atari5200 on Tue Aug 23, 2016 2:50 pm, edited 1 time in total.

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Post by windspirit » Tue Aug 23, 2016 2:42 pm

Yeah that is not healthy behavior. Sorry its been awhile since I have done work on this module so Im a bit rusty on debugging. If you plug something into the cv input but there is no voltage present can you still sweep the entire range of the adc inputs?

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Post by atari5200 » Tue Aug 23, 2016 3:02 pm

windspirit wrote:Yeah that is not healthy behavior. Sorry its been awhile since I have done work on this module so Im a bit rusty on debugging. If you plug something into the cv input but there is no voltage present can you still sweep the entire range of the adc inputs?
Yes- I'm using my ch.2 of my Maths to send a voltage to the CV in, and if I zero it out I can still use the length knob to sweep the entire range. I can actually use the length knobs to sweep the entire range even if I'm putting in 5V as in my experiment, it's just that the offest being added at pin 1 of the ADC is about 1/2 what it should be.

I reflowed all my solder joints already but I may do it one more time just to be on the same side. I swapped out my TL074 and TL072 just in case that had some effect, but since I am reading the expected voltages at either IC I didn't really imagine that would help.

Given that the IC's are measuring the proper voltage, and both of the ADC0820 are sweeping the proper range 0-9V via the knobs I imagine that narrows down the problem areas! I'm not missing any components but it's not outside the realm of possibility that I mixed up a resistor value somewhere, does that seem like something that would cause my problem?

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