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Cresendo pedal not working on Baldwin Howard D910

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  • Cresendo pedal not working on Baldwin Howard D910

    One last issue that I have to take care of my D910. The crescendo pedal does not work. At first I thought it was the switch in the pedal itself. I ordered a new one and replaced. It appears to be working. This is indicated by the crescendo level lights provided on the console. As you depress the pedal the lights cycle from p to FF, but no stop lights illuminate and no sound is issued. No sound at soft, no sound at loud. Any suggestions that could be provided would be much appreciated.

    Bob

  • #2
    Hi,

    If I am not mistaken this is a re-badged Galanti PII.

    If you are getting readout of the LEDs relating to crescendo pedal position, that means the computer is getting it as part of the data stream. From the schematics, it looks like if the crescendo is problematic, that something else is not working the way it should either.

    You might want to check the following ICs, on the interface board which is located on the shelf just above the expression shoes. ICs 3 and 5 (74HC00), ICs 2 and 4 (LM324 op amps). Also IC #6, a 74HC138 decoder chip.

    AV

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    • #3
      Thanks for the details, Arie.
      Note IC's with an HC in the middle are CMOS technology, which has been more short lived than other technologies. Also the inputs are static sensitive compared to other technologies with the same warning sticker on the inventory bag. (the sticker is risable on power transistors, for example) When changing them be sure to wear a static collar connecting your body to chassis ground, and if soldering is involved, use a grounded tip soldering iron.
      Op amps you can often check the + and the - inputs with a DVM to make sure they are at about the same value reference the power supplies or signal ground if you can find one. Use a dip clip and pamona grabbers, shorting the pins together while bumbling around with probes can blow up things.
      You can download the datasheets on these IC's usually at datasheetcatalog.com, although if you are willing to stumble around a bit they will also be available at TI.com, the owner of National Semiconductor (LM line) these days.
      city Hammond H-182 organ (2 ea),A100,10-82 TC, Wurlitzer 4500, Schober Recital Organ, Steinway 40" console , Sohmer 39" pianos, Ensoniq EPS, ; country Hammond H112

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      • #4
        Thank you gentlemen, really appreciate the suggestions although a bit over my head. If nothing is visibly wrong on the board at these locations, first thought would be to replace the board and I have asked general music for a quote. The main boards were $75, not sure how much the smaller board will be.
        Quick question: the insides of the organ were literally caked in dust and dirt.I have used compressed air, soft cloth and lots of hours removing what I could. Is there anyway that dirt and dust accumulation could be causing this on the board? If I decide to jump into the board repairs myself, I guarantee there will be more posts here. Thanks again
        Bob

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        • #5
          Originally posted by RbtWagner View Post
          ... but no stop lights illuminate...
          Are the stops supposed to illuminate with the Crescendo on this organ? Most organs do not do this; i.e. the Crescendo action is generally "blind".

          Greg

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          • #6
            Use of compressed air can cause static buildup which can blow HC parts. I use a damp paper towel and a pick to get into crevices. For serious dirt I also use Family Dollar non-chlorine bathroom cleaner containing ethylene glycol monobutyl ether, on the paper towel. Unplugging and replugging connectors with the power on, or in a dry environment without a ground strap on your body, can also blow up HC parts. Same with changing boards. Unplug the organ and ground yourself to the metal chassis with a ground strap before changing the crecendo board containing HC parts.
            city Hammond H-182 organ (2 ea),A100,10-82 TC, Wurlitzer 4500, Schober Recital Organ, Steinway 40" console , Sohmer 39" pianos, Ensoniq EPS, ; country Hammond H112

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