Penrose debugging: Gate signal fades away

edited March 2015 in General
Have a strange problem on one that I built, the gate signal is fine initially but fades away after a minute (both on the LED and signal)  Part placement if ok and the other two I build work fine.  Any ideas?

Comments

  • what do you mean by fades away? is it getting lower and lower over some time or is it suddenly disappearing.

    there is not much to the gate out.
    AVR digital out -> opamp buffer -> output
    the other chanel of the dual opamp (mcp602) is used for the CV input.
    Is the feedback capacitor (c17/47p) soldered correctly?
  • yup, exactly.  It literally gets lower and lower then disappears (the LED fades as well) 
  • edited March 2015
    I'm stumped with this. 2 out of 3 that I have show this behavior.  When I press on the board around the opamp, it will come back then fade out again.  Reflowed all joints, switched ompamp, problem stays the same 
  • edited April 2015
    what is connected to the gate out?
    anybody else experiencing this?
  • Going into a MFOS ADSR gate in, I'll double check it with another device though to make sure it's not that (although the good one works fine with it).  I still need to probe the pins for the two that dont work and compare with the one that does so I'll report back then
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