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Repair Allen MDC Theater Organ Pedal Contacts?

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    Repair Allen MDC Theater Organ Pedal Contacts?

    Hi There! I just acquired a "free" allen MDC theater organ. About half of the pedals either do not work or play the wrong note, or do not stop playing (cipher). I disconnected the pedals, opened the pedal contact board and used a magnet to determine that the problem was with the contacts, not the pedal mechanism. I do not know how to correct this problem. Do the tiny little glass tubes with the metal pieces inside them need to be replaced, or is it a wiring issue. Help!
    Christine J.

    #2
    It might just be that the pedalboard is not positioned correctly. If the pedalboard (or part of it) is too high, low, close, or far from the reed switches, then some keys will cypher, not play, play the adjacent notes, etc. Often it's just that the carpet is holding part of the pedalboard up. The fix is often to shim the front of the organ up a little so the pedalboard rests in the notch in the blocks on each end.

    Since you have opened the reed switch panel, you might try turning on the organ and running a magnet near the reed switches to see if they all turn on the correct notes. If the reed switches are working, then it's probably an alignment issue.
    Sam
    Home: Allen ADC-4500 Church: Allen MDS-5
    Files: Allen Tone Card (TC) Database, TC Info, TC Converter, TC Mixer, ADC TC SF2, and MOS TC SF2, ADC TC Cad/Rvt, MOS TC Cad/Rvt, Organ Database, Music Library, etc. PM for unlinked files.

    Comment


      #3
      Rereading your initial question, it appears that you have used a magnet to see if the reed switches are functioning correctly. Are some of the notes still dead, wrong, or ciphering while using the magnet? If so, when you hold the magnet (and your ear) close to the switches with issues, can you hear the reed switch click (faintly)? Do any of the reed switches look like the glass is cracked?

      If the reed switches are cracked or non-functional, you may have to replace them. There are a few threads on the forum where members documented that repair.

      If the reed switches are working but the organ still has ciphers, dead notes, or wrong notes, then there might be an issue with the boards or wiring inside the organ. That is outside of my experience, so you'll have to wait for one of the more knowledgeable techs to write back.

      You might also check that all of the magnets on the pedalboard are there and whole. Sometimes they break off and that could be the cause of dead notes.
      Sam
      Home: Allen ADC-4500 Church: Allen MDS-5
      Files: Allen Tone Card (TC) Database, TC Info, TC Converter, TC Mixer, ADC TC SF2, and MOS TC SF2, ADC TC Cad/Rvt, MOS TC Cad/Rvt, Organ Database, Music Library, etc. PM for unlinked files.

      Comment


        #4
        As Sam says, the most common problem with these pedal boards is caused by misalignment. This is frequently the case if the organ has been moved between carpeted and un-carpeted floors as this can change the vertical position of the pedal board relative the console. There are adjustment screws for raising and lowering the reed switches to compensate for this which are accessible on the console with the pedal board removed.
        -Admin

        Allen 965
        Zuma Group Midi Keyboard Encoder
        Zuma Group DM Midi Stop Controller
        Hauptwerk 4.2

        Comment


        • myorgan
          myorgan commented
          Editing a comment
          Also, it is unfortunate you took off the contact rail, as it is difficult to re-align properly. When I had to replace a couple reed switches on one of my organs, I discovered the note can be activated BOTH above AND below the neutral position. Don't make the mistake of believing a sounding note needs to be lowered only. Best of luck with the repair.

          Michael
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