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M42 remote chemical alarm

Discussion in 'General Electronics Discussion' started by Gimli, Mar 21, 2018.

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  1. Gimli


    Mar 21, 2018
    I have a m42 alarm unit from military surplus. It works with batteries in it when you turn it to test the light flashes andthe horn sounds. I'd like to rig up a dummy detector that works with a push button to activate the unit. But I don't want to damage it I just randomly applying voltage and trying to figure out how it works. I also have no idea on how to try to research this well outside my talent set. If that's something one of you can dig up no real effort I would love the info.

    Attached Files:

  2. KMoffett


    Jan 21, 2009
    Google:m42 alarm
    Lots of info and schematics

  3. Gimli


    Mar 21, 2018
    I have, I don't understand stand them
  4. Gargamel


    Aug 15, 2019

    Is there any avenues to purchase the M42 remote alarm? I am looking to purchase new or refurbished units, like 4 of them. Appreciate if some kind souls can produce some leads on this. Thanks
  5. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Sir Gimli . . . . .

    This might just be the least invasive method.
    You see the supplied schematic with the relevant portion of the schematic showing the S1 . . . two pole 3 position rotary switch
    within the YELLOW mark up.

    Normally the unit is connected to the quite involved and bulky M43 detector unit, and then this or additional sited M42 alarm sounding units can be distributed with interconnect of additional units being provided by a 2 conductor WD1TT field wiring pair.

    On S1 . . . it has its top horn / speaker test position, then the option of the deactivation of the horn, for silent operation, in the second lower position with only the alarm lamp illuminating.
    And finally, the third position gives both aural and visual lamp indications.

    What you do is open the connection shown at the RED X and run 2 wires to your " BOGUS " hand carried unit *** with its sole internal pushbutton switch.
    Possibly, it *** being constructed with a cardboard core from a roll of toilet paper, painted RED or Black and a CIRCULAR ball " detector" element of crumpled up alumininnyyumyum foil crammed into one end. The insides gets the pushbutton switch mounted there and the 2 conductor "speaker" wire is then routed out to go over and connect into to the newly added M42 connection points across the opened circuit at the RED X .
    Tightly stuff paper in the tube for the internal filling and as a retainer of the wiring.

    Normally the S1 switch would be in the bottom position for operating as aural and visual detection. The mid position silences the audio.
    BUT NOW, the top TEST position will now activate if used in the horn test position, when you hit the pushbutton for a closed duration.

    TECHNO INFO . . . . .


    Now, will that work out for you ?

    Effectively, now all you have to do is thoroughly shake down a person with some HEAVY probing about the body, then you let her rip upon touching the persons anal orfice.proximity.
    OR . . . le femmes areolas . . . don't ya' just love areolas ?

    73's de Edd . . . . .

    Take me drunk . . . . . I'm home.

    Last edited: Aug 18, 2019
  6. 73's de Edd

    73's de Edd

    Aug 21, 2015
    ADDENDA . . . .
    I see that in a much later proof reading, that my very initial paragraph was not pasted in . . . .to wit . . . .

    Initially test the unit by creating a short across the two external binding posts located at the bottom front of the speaker.
    You work the S1 rotary switch beween its 3 possible positions, fully expecting it to be sounding at the position opposite of the TEST position.
    If so, that would be the connection point of the two wires from fabricated BOGUS detector hand unit.
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