Help ID smoked IC in a dimmer control panel

Discussion in 'General Electronics Chat' started by David Meed, Apr 8, 2011.

  1. David Meed

    Thread Starter New Member

    Apr 8, 2011
    3
    0
    Hi.

    I am trying to replace a smoked IC in a dimmer control panel. The dimmer pack is a Playmate model (6 x 2400W) by Electro Controls (Control Lighting). It has a model number of CL-64B6A3.6. Electro Controls was bought out by Strand and closed many years ago. I am going to try to contact some folks who service these things, but I thought maybe this group could look at a schematic and say - "thats a xxx IC just from the schematic." This unit was likely built around 1982

    It has a 6 slider control panel with a 7th slider that is the master.
    [​IMG]

    There is a circuit board on the master that has an 8 pin integrated
    circuit that controls the master level. This IC has burned up and
    left no identification markings on the top of it (just a charred
    circle).

    It is fed by about 18 Volts DC from the dimmer rack and the dimmers
    appear to operate 0-15v (it may be 0 to -15). The PC board with the
    IC on it is about 2" x 3" and has "PC279 Rev C 5Nov82" as markings on it.


    [​IMG]

    The smoked IC somehow conditions the output of the master fader to drive a PNP transistor which provides a 0-15volt bus which the rest of the faders then use to drive individual dimmer channels.

    Best guess at a schematic is something like below. The 8 pin IC is the question mark. It takes +18 on pin 8 and Gnd on pin 4. No -ve supply. I'm guessing something like a LM324 (but a dual instead of quad?) It's been 15 years since I dabbled much with this stuff.
    [​IMG]

    Anyone care to make a guess what this IC was?

    Thank you

    David Meed
     
  2. David Meed

    Thread Starter New Member

    Apr 8, 2011
    3
    0
    > Anyone care to make a guess what this IC was?

    More research suggests a possibility of LM358 dual op amp.

    Will have to look at it closer in the morning.

    David
     
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,750
    759
    I think it is an OPAMP from the looks of it.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    An LM358 dual opamp is a good guess.
     
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