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Rodgers 340 - need help!

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  • Rodgers 340 - need help!

    Hello Friends,

    As of last week, I am now the proud owner of a vintage Rodgers 340. I've wanted a three-manual theatre organ with second touch for many years, so this is a dream come true! The organ previously belonged to a gentleman in the Atlanta area who recently passed away at the age of 95. It most likely sat unplayed for several years. I was wondering if some of the many experts on this forum could help me fix a few minor problems as I try to restore this beautiful vintage instrument to full functionality.

    My first issue involves the Clarinet rank. It is barely audible, yet puts out a continous loud, rumbling static sound. The only way I can play the organ is to turn the Clarinet's volume all the way down in the first panel of controls.

    The second issue is similar, but involves the Posthorn. It seems to be playing a soft "open fifth" of C# and G# softly in the background. The buzzy tones get louder when I play those keys. Right now, I just keep the Solo expression pedal closed when I am not playing, as this stop is essential to theatre organ style.

    I also have some noise coming from the Tibia channel. It's soft, but sounds like someone put their entire arm down on the keyboard, playing multiple notes at the same time.

    The current speaker compliment is:
    W-6 Brass channel
    W-3 Tibia channel
    W-3 Pedal notes
    M-13 Main channel

    And yes, the glockenspiel works great! : )

    I really want to get rid of all of this extraneous noise before attempting to do any serious voicing. Any help that forum members could give me would be so greatly appreciated! I've worked on vintage Hammonds and pipe organs, but analog technology is something I'm completely inexperienced with. This organ has such a beautiful, warm sound - I really want to get it back into tip-top condition!

    Thank you so much,

  • #2
    Since you are not familiar with analog circuitry it's probably best if you have a service call. If you are in the Atlanta area, see: http://www.chapel-music.com/service.html

    If you are elsewhere, you might add your location to your profile so the members here can guide you to an appropriate service provider.

    The issues you mention are likely in the keyer circuits and/or summing amplifiers. It could also be power supply problems since the organ is so old some of the power supply capacitors might be dried out and need replacing.


    • #3
      Thank you Toodles! I'm now located in Beaufort, SC, about halfway between Savannah and Charleston. The nearest MITA tech seems to be up in Dorchester - Zippy's Organ Service. Does anyone on here have any experience with them?

      I really don't mind doing the work myself if someone can point me in the right direction. The noise in the Clarinet reminds me of a problem I had with my Hammond PR-40, a single NPN transistor that goes bad over time. It was causing hissing and rumbling.

      The power supply capacitiors appear to be in good shape - no visible leakage, thank goodness!


      • #4
        The clarinet keyer in the 340 uses one transistor for every note, so unless you have diagnostic tools like an oscilloscope, it might be hard to figure out which one is a culprit if, in fact, that is the problem Also, some noisy transistors in the summing amp could cause a similar problem, and, of course, there are some possibilities that I haven't thought of. Diagnosing such a problem is a matter of eliminating the possibilities, and usually you start from the back (the speakers) and work to the front (the oscillators) to find the problem.

        Chapel Music is the dealer that covers your area, so it's worth it to at least give them a call.


        • #5
          The first thing I would do is mark the position of each trimpot then exercise them, with power off, through their full range several times then return them to the marked position.
          IIRC there are keyer bias adjustments that can cause strange noises.



          • #6
            Thanks for the suggestion. I adjusted the trim pots for volume, voicing, and the three formants on the Clarinet to no avail, unfortunately.

            I did notice a little blue “dial” on the back side of the first rack. It appears to be connected to the Clarinet or possibly the Kinura. Just seems to be out of place. Does anybody know if it’s supposed to be there? Thanks!


            • #7
              It could have been added in the field, or a revision to the design done at the factory. If you can find out where the signal wire connects, you'll figure out what it does.


              • #8
                Good news - I got the clarinet working today! I kept working the pots associated with this stop and the noise finally just went away. The clarinet tone returned with this adjustment and sounds great. Thank you all for the tips! I’m still trying to solve the noise coming from the Posthorn and Tibia.

                I’ve also got one stoptab that will respond to the general cancel, but not set on any piston. The wiring looks ok, although it’s on the bottom row and a little difficult to see. Anybody familiar with 70’s/early 80’s Rodgers stoptab mechanisms?