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roborobert
Joined: Jan 15, 2013 Posts: 24 Location: austria
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Posted: Sun Nov 03, 2013 5:39 am Post subject:
Klee Calibration Problem Subject description: i'm getting only negative voltages on Pin1 U8 |
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Hey there,
i'm quite puzzled.
after having some great hours with my finished and nicely working klee i went back to the workbench to do the last bits and pieces...
adjusting R42 and R43 for 0V worked nicely. good.
while trying to adjust R34 - R38 for the desired 0,333V etc. i found that i'm only getting negative voltages... on each of the 8 stages - right voltage wrong polarity.
on the programming pots as well as on the voltage outputs, they show up positive again. so it seems i don't have a problem anymore... or do i?
did i maybe overread some important sentence like 'ignore the minus on your dvm' in a haste?
by the way - on first startup, i had a pair of Motorola MC14034BP inserted - they showed some flickering leds and then died, getting hot and smelling like burnt electronics - so i got a some CD4034BP from futurlec and then only had to solve the R20 inserted in the via instead of proper hole problem - from then on everything runs nicely.
maybe this is important.
many thanks for this great sequencer!
best wishes, rob |
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eXisteNz
Joined: Jun 08, 2010 Posts: 48 Location: Italy
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Posted: Sun May 04, 2014 4:14 am Post subject:
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Hey do you worked it out? I'm experiencing your similar issue, i read only negative volage and if i try to rotate trimpot to reach positive voltage a then i Can reach only until -0,06 or -0,16... |
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roborobert
Joined: Jan 15, 2013 Posts: 24 Location: austria
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Posted: Tue May 06, 2014 7:10 am Post subject:
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no, i wasn't able to solve the problem.
i didn't care about the minus anymore since the outputs are performing as they should (positive voltages in the right range)
but i also still have problems reaching the right voltages on the scaled outputs - guess i have to change some corresponding resistor values (which is properly documented), but didn't get to it...
best, r |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Tue May 06, 2014 9:26 pm Post subject:
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Actually the fact is the voltages are supposed to be negative. Threw me the first one I built too. |
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eXisteNz
Joined: Jun 08, 2010 Posts: 48 Location: Italy
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Posted: Tue May 06, 2014 11:26 pm Post subject:
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Yeah while i was reading some of The Scott posts, he said that although The manual refer this voltages ad they're positive, these are NEGATIVE. It's an error. In fact it works fine! |
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roborobert
Joined: Jan 15, 2013 Posts: 24 Location: austria
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Posted: Wed May 07, 2014 4:52 am Post subject:
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aha! good to know
do you remember where you found that post? not that it's so important, but maybe there's some more i havent figured out yet...
best,R |
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eXisteNz
Joined: Jun 08, 2010 Posts: 48 Location: Italy
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Posted: Wed May 07, 2014 5:42 am Post subject:
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Oh well, Now i can't remember exactly, but i found it while i was searching for "calibration issues"...maybe it was on muffwiggler? I really can't remember! |
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roborobert
Joined: Jan 15, 2013 Posts: 24 Location: austria
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Posted: Wed May 07, 2014 6:13 am Post subject:
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ok, thanks |
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jksuperstar
Joined: Aug 20, 2004 Posts: 2503 Location: Denver
Audio files: 1
G2 patch files: 18
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Posted: Sun Jan 04, 2015 4:18 pm Post subject:
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I just had this same "problem"...thankful this thread exists. I did have to trace through the schematics to realize there was a double inversion in the amplifier path.
Still, I ended up doing the calibration at Analog board J13, Pin 5 (the CV output for A). Positive voltage, and it accounts for the opamp after U8 called for in the calibration sequence. |
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eXisteNz
Joined: Jun 08, 2010 Posts: 48 Location: Italy
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Posted: Mon Jan 05, 2015 1:38 am Post subject:
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Good to know you found it useful, have fun !!! |
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sduck
Joined: Dec 16, 2007 Posts: 459 Location: Nashville
Audio files: 5
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Posted: Thu Jan 08, 2015 7:38 am Post subject:
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It's all probably in the Build and Applications thread stickied above this. Yes, it's a large and daunting thread, but covers a lot of stuff, and is where questions like this should go also. I read the whole thing when I built mine, and keep up with it since then. |
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