Component Identification

Discussion in 'The Projects Forum' started by jsthomps, Apr 2, 2010.

  1. jsthomps

    Thread Starter Member

    Mar 30, 2010
    15
    0
    Hi all,
    I trying to build a sound circuit that was used in a 1974 pitch and bat arcade game. The circuit plays crowd sounds depending on whether a hit or a home run has taken place I have a schematic for the circuit but I'm having some trouble identifying all the components and/or what can be substituted in their place:

    1. Op Amp
    2. Zener diode (What should it's breakdown voltage be?)
    3. All transistors
    [​IMG]

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    Any help would be appreciated
    Thanks,
    Scott
     
  2. kkazem

    Active Member

    Jul 23, 2009
    160
    26
    Hi,
    The parts list shows all the diodes are the same p/n, DA1704, which is cross-referenced to the ubiquitous 1N4148 signal diode, yet d6, which the schematic shows as a zener diode, is also ID'd in the parts list as the DA1704. The amp is just a pre-amp to boot the audio signal to about the 1V level, which can be easily made from most any op-amp with a gain of perhaps 10 to 100. Although I can't cross it, the NPN transistors can with near certainty be made with the 2N2222 or PN2222, since they are also all the same part number. Since the AC input to the power supply section is 30 VAC, the Zener must be between 15V and 24 V breakdown, or perhaps even a few volts higher, but not too much higher or you'll have reliability problems.
    Good Luck,
    Kamran Kazem.
     
    jsthomps likes this.
  3. jsthomps

    Thread Starter Member

    Mar 30, 2010
    15
    0
    Kamran,
    Thanks for the excellent feedback. One thing though ... the op amp directly drives an 8ohm 2 1/2 inch speaker. Does that change you option re the op amp?
    Thanks,
    Scott
     
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