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  • Missing Tone

    Hello gents. While playing today, I noticed I have a missing tone on a ‘62 B3. I’m quite confident it’s a new issue, and not something that’s been there but hadn’t noticed.

    Lower manual only. F# key (43). The 16’ drawbar on ALL lower manual preset keys, It’s only this key, this manual, this drawbar. I’ve checked every key with every drawbar, and everything else is operative. Occasionally it will sound faintly if the key is pressed lightly - - if I hit the key hard, it will no longer sound.

    Looking for general suggestions on where to look first, trying to eliminate any guesswork and wasted time. (I fully realize that an online diagnosis is far from ideal.) Thanks.
    Last edited by Rich V; 10-13-2021, 03:51 PM. Reason: Further investigation.

  • #2
    Standard Missing Tone Procedure:

    1) Using one of the lower manual drawbar presets (A# or B) pull out only the 8' (lowest white) drawbar.
    2) Start on the lowest C playing key on the lower manual, which will be Tone 13, and play up chromatically one key at a time, counting as you go, till you find the missing tone. This will take you from Tone 13 to Tone 73.*
    3) Run the same procedure on the Upper Manual to confirm the same findings on both manuals.
    4) With the missing tone numbers recorded, find the Hammond service manual page that shows the terminal strip tone numbers. They are not in sequential order on a B3. Locate the relevant terminal.
    5) Connect an alligator-clip wire or other jumper wire to the terminal in question, and touch the other end to one of the preset panel busbars. If the tone is present at the terminal strip, the tone will sound.
    6) Check the solder joint on the terminal, and check to see if the wire attached to it is broken.
    7) If the tone is present and the joint at the tone generator terminal strip looks good, the break is most likely where the harness attaches to the upper manual. The upper manual terminals are in order from 13 to 91. In more unusual cases, the wire may be broken somewhere else.

    If the tone is missing at the tone generator terminal strip, it gets trickier. You'll have to look at the wiring on the top of the tone generator to see if one of the fine wires on the tone filters is broken.

    *To check Tones 74-91, push the 8' drawbar in and pull out the highest drawbar. Start on the 3rd C and play up two and a half octaves to F#.
    I'm David. 'Dave' is someone else's name.

    Comment


    • Rich V
      Rich V commented
      Editing a comment
      Excellent, thanks David! On it…

    • Rich V
      Rich V commented
      Editing a comment
      So, it seems the instructions you’ve provided would be relevant for a tone missing on both manuals… but that’s not the case here. Using your procedure, the only missing tone on the lower manual is F# 31. Same procedure on upper manual reveals no missing tones.

      On Hammond Wiki, a missing tone on one manual only suggests the problem may be:
      - remedied by a bus bar shift. I did this to varying positions but no result.
      - the usual striking of the key repeatedly. This had no result.
      - broken resistance wire in the manual. Perhaps, but I’ve not moved/jarred/etc this rig in forever.
      - bad connection at manual terminal strip. Haven’t check this, yet.

      Any other thoughts are welcome!

      UPDATE: FYI, lower manual drawbars other than 8’ reveal other F# dead tones as well as B dead tones and one D dead tone up and down the lower manual. All dead tones associated with single drawbars revealed just one dead tone on the manual. (Hope that’s clear…)
      Last edited by Rich V; 10-13-2021, 07:40 PM.

    • enor
      enor commented
      Editing a comment
      If the same frequency is missing from ALL places on the manual where it should appear, you're in luck. That means that your problem is in the harness between the upper and the lower manuals (there's no risk of tedious resistance wire repair).

  • #3
    Enor seems to be correct. I identified the missing tone to connection #43 on the terminal strip. Both connections on the strip were solid, but I reflowed them anyway. No joy. However, simply moving the loom with a mild touch brings the note in and out. Going to check the manual connection.

    Comment


    • #4
      The way Hammond attached the wiring harness to the manuals was a bit idiosyncratic, so it will help to be able to picture it in your head.

      One continuous wire runs from the tone generator to the upper manual AND the lower manual for each tone. At the upper manual terminal strip, they slit the wire insulation, bent the wire double, and pushed the doubled/bent part through the terminal (and soldered it). They left part of the insulation intact. Then they soldered the end of the wire to the lower manual terminals. What can happen is that the wire itself breaks at the upper manual terminal, but it's still held in position by the insulation. It can break either on the TG side or the lower manual side. If it breaks on the lower manual side, you'll have the tone on the upper manual, but not on the lower.

      That's why the procedure I described does, in fact, tell you what you need to know.

      To fix the problem, you have to find the relevant wire, cut the insulation holding the wire in place at the upper manual, put the wire back through the terminal, and solder. With the older cloth-insulated wires, you just push the insulation back. With later plastic-insulated wires, you may have to strip a bit of insulation, very carefully so as not to nick the wire.

      But if you move the harness and have the tone come and go, there's definitely a break in that wire somewhere.

      Edit: And, of course, you've got to raise the upper manual to get to all this and work at odd angles.

      Also, yes, each tone is wired to a number of contacts inside the manual. The key is to keep track of the tone numbers and where they are located relative to the keys. If you aren't making careful comparisons of the tone numbers, drawbars, and key locations, you'll confuse yourself and anyone trying to help you.
      I'm David. 'Dave' is someone else's name.

      Comment


      • Rich V
        Rich V commented
        Editing a comment
        Thanks again, David. I think for this one, I’m going to have my tech, Paul T., handle this one. I know what I can and can’t do… and sometimes that’s half the battle.

      • Rich V
        Rich V commented
        Editing a comment
        So David, I decided to check it out based upon your detailed instructions. Lower manual connections were all solid. Upper manual… I see exactly what you mean about the wiring, bent at 180 degrees. And that’s where I found the break. The downward wire had broken but was still attached by the insulation. Removed everything, cleaned the terminal, resoldered and back in business. Thanks again!

    • #5
      The broken wire… tough to see as it was hanging by a thread - literally. That cloth insulation made it simple to simply snip, push back to solder, then slide back up to the terminal.
      Attached Files
      Last edited by Rich V; Yesterday, 03:52 PM.

      Comment


      • #6
        Well done! It's always good when the fault turns out to be the typical one you'd predict.
        I'm David. 'Dave' is someone else's name.

        Comment


        • #7
          Final question…. I also found a different “repaired” wire going from the upper manual terminal to the lower manual terminal. There’s a twist-and-solder repair halfway down the wire, wrapped with (falling off) electrical tape. The soldering at the upper manual terminal is atrocious.

          What modern wire would be suitable to replace the entire wire from the upper to lower manual?

          Comment

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