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Old motorola IC question...

Discussion in 'Electronic Repair' started by al, Feb 7, 2004.

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  1. al

    al Guest

    Hi all.

    You guys have never let me down before, so here goes:

    I have an old (about 17 years) Oster "kitchen center" food
    processor/mixer/you-name-it appliance that has a dead electronic speed
    controller. The control is a small fairly simple circuit board. There
    are 2 IC's on the board, one of which is an op-amp. The other has the
    Motorola "M" symbol on it and is marked with the part number "SOC
    742A" it is a 6 (yes, 6) pin plastic DIP. I have been unsucessful in
    locating any data saying what this chip is.

    I have found several places on the web that list that as available
    old stock inventory, and they will be glad to sell me some with a
    $500.00 minimum order.
    But no data sheets or whatever.

    Any ideas?? A source for this part, a pinout, or any info would be
    much appreciated.

    I know I should probably just replace the whole thing, but it
    otherwise worked great, we have the 57 attachments that go with it, it
    is verry well made and my wife loves it. I would buy the whole circuit
    board, but Oster no longer sells parts for this unit. Besides, I am
    really, really cheap and I hate to trash this over a what is likely a
    $1.00 part.

    Thanks in advance for any suggestions.
  2. JURB6006

    JURB6006 Guest

    I would highly suspect it to be an optocoupler.

    That's all I got.

  3. Tweetldee

    Tweetldee Guest

    It's unlikely that the IC that you refer to as an opamp is actually an
    opamp. That IC is most likely to be a triac.
    The 6-pin device is likely an optoisolated triac driver. Either or both of
    the IC's are bad. The opto triac driver can be a MOC3022 or MOC3023, and
    the triac can be a Teccor sensitive gate triac such as the L4004L or
    The circuit should be very simple, as you indicated. It would help confirm
    the parts selection if you could draw it out and post it. Resistor and
    capacitor values are important.

    Dave M
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