Forum Top Banner Ad


Ebay Classic organs



No announcement yet.

missing tone on M100

This topic is closed.
  • Filter
  • Time
  • Show
Clear All
new posts

  • missing tone on M100

    Hi there,

    I have a weird problem on my M100.

    It is missing a tone on both manuals.
    It is frequency / tone #36 (should be a B on the fundamental (3rd) upper drawbar).

    I have #72, so it is not a stuck tone wheel.

    I also checked the freq. itself by connecting the coil output from the TG to a drawbar.
    The note is there, I can hear the tone in correct tune.

    So I thought it is a broken wiring to the manual.
    As the lower is connected via the upper manual (and the freq. is missing on both), It should be a broken wire from the TG to the upper manual at least.

    I then checked the lower manual terminal (because of easy access) for this freq. and connected this to a drawbar.
    The tone is also there!
    Now I am lost.
    Why is the tone not there when pressing a related key (with drawbar pulled), but is there at the terminal of the manual?

    Ok, it could be a broken connection inside the manual from the terminal to the key contacts.
    But why should it be exactly the same issue on the upper manual??
    All other key contacts work perfectly...

    Any other ideas than completely disassembling the manuals to check the connections there?
    Any comments are really appreciated!

    Many thanks, Mark.

  • #2
    The wiring from the TWG goes to the upper manual where the wire is formed into a tight U with the insulation pushed back on soldered then on to the lower. Since you have tone on the lower terminal but not on the upper or lower manuals when the key is depressed I would suspect that the ground on the TW pickup is loose or corroded. Loosen and re-tighten the set screw for tone 36.



    • #3
      Hi Jim,

      thanks for that hint. I completely missed to think from that side....
      I will try this.



      • #4
        Had the same puzzler awhile ago. Reflowed solder on the terminal strip for that tone and it reappeared.
        A100/251 A100/147 A102/222 B2/142 BV/147 BCV/145 M3/145 M102/145 M111/770 L101/760 T222/HL722 M111/770 no B3/C3!


        • #5
          Thanks Pete,

          worth a try.


          • #6
            Hi Jim,

            I tried to follow your thought, no success so far.

            If the ground would be loose, wouldn't there be no tone at all on the terminal as the circuit was open?
            My understanding is that by depressing the key, the corresponding frequencies from the manual terminals are forwarded to the single bus bars and so to the drawbars.
            Feel free to bring me up to speed :)



            • #7
              It has to do with the load impedance. I had a tone that would meter ok (high impedance) but no tone through the manuals (low impedance). Pete's suggestion is also something to try.



              • #8
                Thanks guys, for you support.

                Finally, I got it sounding again.
                I really measured a lot and tried different things - with your help.

                After redoing all and all again, I started resoldering all connections just to make sure. In the end it turned out to be a bad soldering at the tg which it seems I always shorted during the measurements.
                It was strange as the lower and upper end were soldered OK, but in between there seemed to be a thin break.

                In the end I am happy...and can now focus on fixing my percussion issue.

                Thanks a lot to the forum!