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echoer
Joined: Dec 10, 2009 Posts: 40 Location: lawrence, ks
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Posted: Sat Mar 26, 2011 2:38 pm Post subject:
Love this sequencer - one little problem has me stumped Subject description: Step 1 always outputs to Bus 2 |
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Every time the sequencer is in the first step, it outputs the gate and trigger to the B Gate bus regardless of which way the switch is telling it should go. The other steps work properly and output to wherever the switch is telling it to.
- tested the switch multiple times
- quadruple checked wiring to the switch
High quality parts used throughout. CD____BE ICs were used throughout.
Other than a couple wiring harness issues this build went smooth. Any ideas as to what could be going on here would be greatly appreciated.
Thanks in advance. _________________ - jason
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echoer
Joined: Dec 10, 2009 Posts: 40 Location: lawrence, ks
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Posted: Sun Mar 27, 2011 4:55 pm Post subject:
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After some more experimentation the Stage 1 Programming Pot changes the CV for the entire sequence acting like a Master Tune Pot.
I assume both of these problems are related. Bad IC? _________________ - jason
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Mon Mar 28, 2011 3:29 am Post subject:
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Judging by the schematics, check the signal path of Stage 1:
Analog Board:
- swap U1 and U2 and check if that makes a difference. If it's a chip problem, and Stage 9 was working before, then Stage 1 should work now and Stage 9 should stop working. Also check to make sure U1 is properly seated and that there aren't any pins bent underneath. This happens!
- the gate bus for Stage 1 goes to J2 on the Analog board. Check diode D13 for the proper orientation.
- check for shorts in and around D13, J2 and pin 13 of U1
Digital Board:
- check for shorts around J6, namely pin 8. _________________ Sneak-Thief - raw electrofunk |
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echoer
Joined: Dec 10, 2009 Posts: 40 Location: lawrence, ks
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Posted: Mon Mar 28, 2011 4:18 pm Post subject:
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Hey thanks Sneak. Tried your recommendations. No luck.
Swapped U1 and U2 and double checked proper alignment in the sockets
D13 is properly aligned and tested
Checked for shorts around D13, J2 and pin 13 of U1 on the Analog Board; J6 on the Digi. All good according to my eyes and multimeter.
I'll keep probing. Any more ideas would be greatly appreciated. Arghhh. _________________ - jason
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Mon Mar 28, 2011 4:22 pm Post subject:
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What about the pot for Stage 1? Is it wired properly? Is the pot working? _________________ Sneak-Thief - raw electrofunk |
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echoer
Joined: Dec 10, 2009 Posts: 40 Location: lawrence, ks
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Posted: Mon Mar 28, 2011 4:42 pm Post subject:
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Yep yep. Checked that as well. I disconnected all the headers and checked the board again. I will go through the wiring one more time, but I checked everything with the multimeter to check my connectors the first time I assembled it. Maybe I will find something this time.
BTW, listening to the live a Club Moo. It is great! _________________ - jason
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Scott Stites
Janitor
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Mon Mar 28, 2011 5:55 pm Post subject:
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Wow, that is a weird one!
When stage 1 is not active, do the other stages work normally (voltage output and gate bus output)?
Cheerios,
Scott
Edit:
Quote: | The other steps work properly and output to wherever the switch is telling it to. |
Never mind..... _________________ My Site Last edited by Scott Stites on Mon Mar 28, 2011 6:32 pm; edited 1 time in total |
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Scott Stites
Janitor
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Mon Mar 28, 2011 6:13 pm Post subject:
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I take it, when Stage 1 is active, the stage 1 pot affects the other pots, and Stage 1 generates an output on Bus B. Sooo...two more questions:
First of all, turn Stage 1 on and set all of the other stages to off, and load that pattern so only Stage 1 is active. Do not clock the Klee, let Stage 1 remain on.
1. Does stage 1 also generate a gate bus event on Bus A regardless of the gate bus switch position (if it's set to B, does it generate a gate on the A output?)? You can tell by measuring the A and B bus outputs. If you're set to 'A' on Stage 1, the B Gate Output (normally) should be 0V or so. As you report, it will probably be either +5 or +10V. Switch the Bus to B and look at the Gate A output - it should be low (around 0V). If it is high, then Stage 1 is erroneously affecting both Gate Buses equally.
2. When Stage 1 is active, does it light any of the other Stage LEDs that should be off? _________________ My Site |
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Scott Stites
Janitor
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Mon Mar 28, 2011 6:45 pm Post subject:
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Final hail mary before I sign off:
With the connectors connected to the PCBs.....
1. Turn the power off and measure the resistance between the top connection of the Stage 1 pot and the top connection of the Stage 2 pot. Let me know what the measured resistance is.
2. Measure the resistance between the center tap of the Stage 1 pot and the center tap of the stage 2 pot. Let me know what the measured resistance is.
3. Measure the resistance of the 'bottom' tap of the Stage 1 pot and the 'bottom' tap of the Stage 2 pot. These should read close to zero ohms - this is the common ground connection between the pots. Let me know what the measured resistance is.
4. Measure the resistance of the 'bottom' tap of the Stage 1 pot and ground. Again, this should be very low resistance. Let me know what the measured resistance is. _________________ My Site |
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echoer
Joined: Dec 10, 2009 Posts: 40 Location: lawrence, ks
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Posted: Mon Mar 28, 2011 7:52 pm Post subject:
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Hi Scott. Thanks for your thoughtful replies. I will get it wired back together tomorrow and get some answers for you. Can't wait to get this Klee rollin' properly. Talk to you soon. _________________ - jason
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echoer
Joined: Dec 10, 2009 Posts: 40 Location: lawrence, ks
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Posted: Tue Mar 29, 2011 2:12 pm Post subject:
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Fixed. There was an error at Pin 8 of the P106/P202 wiring harness. Works perfectly now. Thanks to Scott and Sneak! _________________ - jason
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