My build log - missing parts, questions and suggestions

Discuss Nava construction and related issues
  • beeb
    Posts 96
    Joined: May 18th, '16, 20:15

    Cheers Patrick, I was about to solder the LCD tonight, good that I read this
  • drifter7508
    Posts 154
    Joined: Apr 19th, '16, 13:35

    comboy wrote:Daaaang! I found the problem!
    The right 'standoff' from VR14 is placed directly above a via carrying the signal from R12A to the 4069 VCC pin (14).
    Since the standoff is connected to GND and touches the untented via when the pot is fully inserted, it shorts the output of the opamp down to GND, eliminating the 4069 supply voltage.

    This was a hard one to find! but at least the mid tom is working now, too :)
    I'm just wondering.... can this be a source of the noise levels that many have? I have not done this fix since mine worked just fine. But could there be interference between these points when they are so critically close?
  • jcc3
    Posts 5
    Joined: May 1st, '16, 05:22
    Location: Detroit

    my BOM's 100pf ceramic cap are missing too, as well as a buttload of other parts :(
  • User avatar
    hofmann25
    Posts 268
    Joined: Jan 26th, '16, 21:30

    comboy wrote:exactly - the tiny little hole.
    That's what made it so hard to find.
    The corner of the pot poked exactly into this tiny hole :geek:
    Is this linked to my problems Comboy do you think? viewtopic.php?f=24&t=1156#p7165

    Which one is the problem?>>>
    Image

    OR?

    Image
  • User avatar
    hofmann25
    Posts 268
    Joined: Jan 26th, '16, 21:30

    comboy wrote:Daaaang! I found the problem!
    The right 'standoff' from VR14 is placed directly above a via carrying the signal from R12A to the 4069 VCC pin (14).
    Since the standoff is connected to GND and touches the untented via when the pot is fully inserted, it shorts the output of the opamp down to GND, eliminating the 4069 supply voltage.

    This was a hard one to find! but at least the mid tom is working now, too :)
    Ive tested continuity between GND and Pin 14 of IC22. No continuity. In fact not one pin from IC22 is connected to GND. Does that mean my problem is not the GNDing of the VR14 stand off?

    :arrow: R12A is also not connected to IC22 (4069) pin14. I can't see properly on the schematic if it is supposed to. 909 and Nava Schematic.

    Thanks! :D
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