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corrosion digital / analog signal connector switch

Discussion in 'General Electronics Discussion' started by morphingstar, May 19, 2012.

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  1. morphingstar


    Mar 1, 2012
    LIMITS: This post asks help from people who are experienced in electronics where corrosion is a considerable problem. Please read, don't add if you don't know.
    Corrosive ambiance: Pacific coast, breathable air.

    I do not have any circuit diagrams. The circuitry uses SMD.

    I have here circuitry containing
    digital circuitry (5 vdc)
    analogue circuitry 0.5 mv, then amplified 600 mv ac (50-15000 hz)

    Switches, push buttons, probably not sealed, miniature, digital signal, on/off push
    gold plated, pcb and cables, mostly digital signals.
    Ordinary audio connectors, 1/4 jack, multiple pin, non audio are gold plated

    The mechanical push buttons are connected to a non-ringing microprocessor circuit, I hope. Thought guide: If the switch is poor it may send more thean 1 signal per push.

    General construction:
    The mechanical switches and the mechanical connectors have no wires between them, all this hardware is mounted on prints (pcb) or connected to printed circuits via cables.
    There is also a digital display, showing some results, and more "errors" when environments is getting warmer. As I see it, the display shows what it should not (value=true), this being misbehavior of the software, the display hardware itself is ok.
    (DEF: Misbehavior of the software (here): It does not respond with the correct result.)

    Problems (tons :) ):
    The result of pressing a control switch varies: No response, correct response, wrong response.
    Recently when things went very bad with the control switches response, I "strangled" the 12 wired connector, pulling in/out while twisting. Process looked painful, and worked. The cable holds various digital signals. Indicates corrosion problems, invisible at connector pin surface.
    The number of digital operation faults seems to rise with temperature, low <28°C, increasing with >29°C. In an analogue circuit this might be called a drift, or similar. In digital circuits ???. This happened for years, getting worse. Not an illusion.

    I tried
    Contact spray
    It worked somewhat, how much due to spray and how much due to friction on the connector pins, is hard to say. No access to push button contacts.
    Temperature test
    Put the digital circuitry into an extra warm area (plastic cover, heater blowing). Contrary to my expectation the error did not noticeably increase. Meaning the temperature problem exists but could not be verified with the means I have.

    Some of the analogue signals (non-audio) control digital operations: This is comparable to a circuitry inside a digital voltage meter measuring an dc (analogue) voltage*. However, the major signal input appears to be stable, doing nothing it should not do. Mentioned for completeness, don't get hooked on this unless highly inspired. :) [* can't remember the term for this conversion

    Who 's got the needle in the hay stack ?

    Digital part
    analogue part
  2. GonzoEngineer


    Dec 2, 2011
    What are you asking?
  3. morphingstar


    Mar 1, 2012
    What I am asking?
    How to get rid of crack noise, signal damping, interruption all related to:
    1) Audio connectors
    How to get rid of "ringing" or whatever a switch does which controls digital circuitry.
    2) Electromechanical control switches driving digital circuitry producing not the desired result.

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