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LetterBeacon
Joined: Mar 18, 2008
Posts: 439
Location: London, UK
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 Posted: Mon Mar 11, 2013 5:19 pm Post subject:
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| I'd be up for a board! |
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emdot_ambient
Joined: Nov 22, 2009
Posts: 669
Location: Frederick, MD
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Luka
Joined: Jun 29, 2007
Posts: 996
Location: Melb.
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oldbob
Joined: Jun 18, 2008
Posts: 12
Location: Australia
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| Posted: Thu Mar 14, 2013 2:31 pm Post subject:
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Count me in for PCB, thanks.
oldbob
So many modules, so little time. |
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wmonk
Joined: Sep 15, 2008
Posts: 483
Location: Enschede, the Netherlands
Audio files: 12
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| Posted: Sun Mar 17, 2013 11:58 am Post subject:
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I finally got around building mine, and after a lot of wiring (yuck, those switches o_O) it basically works.
Although.... my CV output gives a nice and steady -13.92V. (Indeed /the/ typical value of a TL074 clipping.)
I would like to fix this of course. What I already checked: voltage on potentiometer wiper is okay. Voltage on the PCVS bus is okay.
Voltage on the PORT1 pin is -13.92V. (again that magical number).
So, what should I do to fix this?
Cheers,
Woody
Edit: forgot to mention that I'm using V2.0 firmware.
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Kits for synthesiser modules in Europe |
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ryktnk
Joined: Apr 24, 2008
Posts: 175
Location: london
Audio files: 1
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| Posted: Sun Mar 17, 2013 1:47 pm Post subject:
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| wmonk wrote: |
Voltage on the PORT1 pin is -13.92V. (again that magical number).
So, what should I do to fix this?
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Hello
Oh dear, that sounds a bit strange.
Please check there are no shorts around the TL704.
PORT1,2 just feed the big capacitor that hangs on an input
of the TL704 [simple lag circuit] so have a look
at the big cap for any shorts [sorry I haven't go my circuit with me
so can't tell you the part no.s at the moment  ]
I am away on business this week, so cant check my
circuits this week.
I will try and work out some help when I am back next week, sorry.
-ryk |
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emdot_ambient
Joined: Nov 22, 2009
Posts: 669
Location: Frederick, MD
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| Posted: Wed Mar 20, 2013 7:52 am Post subject:
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| ryktnk wrote: | I am away on business this week, so cant check my
circuits this week. |
That's what DropBox is for 
_________________
Looking for a certain ratio since 1978 |
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wmonk
Joined: Sep 15, 2008
Posts: 483
Location: Enschede, the Netherlands
Audio files: 12
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| Posted: Wed Mar 20, 2013 8:43 am Post subject:
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Well, replacing the opamp fixed the problem. 
I now have it working and I love it! One problem still exists, whenever I turn a stage to three steps, it skips the whole stage it altogether.
Cheers,
Woody
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ryktnk
Joined: Apr 24, 2008
Posts: 175
Location: london
Audio files: 1
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| Posted: Tue Mar 26, 2013 12:49 pm Post subject:
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| wmonk wrote: | Well, replacing the opamp fixed the problem.
I now have it working and I love it! One problem still exists, whenever I turn a stage to three steps, it skips the whole stage it altogether.
Cheers,
Woody |
Hello
Sorry for the delay - back on dry land !
Glad the CV problem is fixed.
The stage count problem, sounds a little strange.
Can you check the voltage on the CT [stage count] bus.
It is pin 18 of the PIC chip, or from the CT pad on the PCB.
If you stop the clock on the seq, and then push the PREV button
to get to stage "1"
Adjust the Stage Count for stage "1' and check the CT voltage:-
Use a DVM to check the CT voltage [pin 18 of PIC].
It should read 0V if the stage is set to "1" count
and approximately
0.8V for "2" count
1.4V for "3" count
2V for "4" count
2.6V for "5" count
3.2V for "6" count
3.8V for "7" count
4.6V for "8" count
Perhaps also check the stage Mode MD voltage [pin 19 of PIC, of MD pad on PCB]
Adjust the Stage Mode for stage "1", and check the voltage for each setting.
0V for "-"
1.8V for "1"
3.1V for "11"
4.5V for "1-"
Also double check carefully there are no shorts on the PCB
between any of the PIC chip pins, and make sure that MD, CT,MAX
MODE,SDIV wires from the switches and pots are wired to their
corresponding pads on the PCB.
Lastly, it might be worth checking all the diodes from the
POT1-8 bus, to make sure their polarity is correct.
Please refer to the Panel Wiring PDF on the first page of this thread.
Let me know how you get on.
-ryk |
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panda30y
Joined: Apr 12, 2009
Posts: 17
Location: Detroit, Michigan
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| Posted: Fri Apr 05, 2013 9:07 am Post subject:
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| If you do another run, I'd be interested in 2 or 3 board and switch sets. |
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synchromesh
Joined: Dec 02, 2007
Posts: 4
Location: Norfolk, England & Wellington, New Zealand
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| Posted: Wed May 01, 2013 9:30 am Post subject:
Yes please! |
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Hi, I'd be keen on a couple of PCBs & PICs myself, once version 3 is ready. This seems like a highly-regarded sequencer module, and I think it would be great.
Thanks very much for putting this together! |
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