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Allen 301b 32' Contra Bass Stop

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  • Allen 301b 32' Contra Bass Stop

    Worked when I first fired up the organ but has since quit working :'( However my other 32' bass pedal stop (Contra Bourdin....sp?) works fine. I know its the $64k question but where should I start to look...without a service manual? I have already checked the obvious....the wire connections behind the stop switch tab...they look good.

  • #2
    The stops are activated by switching to ground so be sure the stop bracket is grounded and the switch is working. There should be -27 volts when tab is off, zero volts when on. The Contra bass 32 tab goes directly to the MOS board by way of plug 20, pin 28 on the mother board. There is a 27k resistor to provide a -27 volt bias. It does not use the stopboard array.

    td
    Servicing electronic organs since 1969.

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    • #3
      Thank you Dave! I will check into that as soon as I get time. Your information is very helpful and appreciated!

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      • #4
        One of the "butterfly leaf" contact strips was bent away from the toggle switch contact bar strip.....don't know how but after carefully bending it back this stop works well now :-)

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        • #5
          Per the PM here's the connections to drive your powered sub from the speakers if you don't have speaker level input on you sub.
          Of course you just need one transformer.

          td

          Click image for larger version

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          Servicing electronic organs since 1969.

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