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Weird rotary encoder

Discussion in 'Electronic Repair' started by N_Cook, Apr 27, 2009.

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  1. N_Cook

    N_Cook Guest

    Mode selector switch on a Boss DD6 effects delay peadal. Looks just like the
    other 3 green case subminiature pots each marked B50K , by Alpha. Nothing
    external to indicate the 7 posistion "switch" is different. Inside a second
    properly molded-in internal endstop as well as the normal one, so track is
    limited to 3/5 of normal full track.
    So if wiper breaks, due to grease, then pedal has a mind of its own which
    mode it wants to be in. When cleaned out measures 0, 3k, 8.1k, 13.4,19k,
    25k,30.6K in the 7 positions and over full track 48.6K.

  2. What exactly is the question you are asking?
  3. N_Cook

    N_Cook Guest

    Anyone else come across the like?
    Pot used as a mode switch yes, with vague areas around the knob designating
    the mode but not ever seen a dedented pot before. And how are they assembled
    at manufacture.? Externally there is absolutely no different appearance
    between the "switch" ones and the pots, I've looked under an inspection
    lamp, no odd dot in the molding or any other difference. If you turn the
    shaft then it clicks into the dedents, being the only difference, but that
    is not visual.
  4. N_Cook

    N_Cook Guest

    Yes but not functioning as a switch, relying on high linearity and
    non-variation of resistance for firmware interpretation.

    There is a difference to the pots, they are ink stamp marked 2G on the side,
    this "switch" one is marked 2H7
    Laid out on a clothes peg and mm rule. Third part is the track section
    inverted to show the second green endstop. The fourth image unclear in pic,
    as buried in the body, holds the dedent wiper. One detent that shows is to
    the right of the purple > and the endstop arm marked A
  5. Eeyore

    Eeyore Guest


  6. Eeyore

    Eeyore Guest

    Batch code most likely. Taiwan Alpha stick to quite conventional markings for
    resistance and curve e.g. 10KA

    That's a horrible picture. I can hardly make anything out.

  7. Eeyore

    Eeyore Guest

    I was wondering the same.

    No ? Crikey ! I was using them nearly 30 yrs ago.

  8. Franc Zabkar

    Franc Zabkar Guest

    The Alpha 16mm miniature carbon linear pot in Fig. A is supplied in
    three flavours -- no detent, centre detent, and 11 detents:

    - Franc Zabkar
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