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I have parts and a service manual for a Conn 720

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  • I have parts and a service manual for a Conn 720

    Greetings all,

    I have loved having a Conn Artist 720 electronic organ for many years. Unfortunately, during its life in basement storage this last year, mice have wreaked havoc, and the house is being sold. This instrument has lost most of its value. (I plugged it in, turned it on, lots of popping sounds, phantom notes, strange noises, some keys no longer working.) I am sorry to say it will be broken down into pieces and disposed of.

    I have a service manual that I am willing to give away for the cost of shipping ($3.00)
    I can also take off some parts if you contact me in the next couple days. I am willing to remove small easy to reach parts for no cost, so long as shipping is paid. Going to sell most of the tubes elsewhere, but willing to give some away if anyone needs them.

    Should anyone somehow want the instrument and be willing to take the whole thing, it is in Waterville, WA (North-Central/Eastern Washington).
    Last edited by zylstra555; 04-03-2017, 12:38 PM.
    My instruments:
    Home: A late 50's to early 60's Conn 720 (tube powered, of course)
    One reed organ; in pieces at the moment pending a helping hand to do some gluing.
    Two pianos (upright grand and a spinet) and an accordion (Hohner)
    Hammond A-105 with Leslie speakers
    1979 Allen 123-C (MOS1) digital computer organ

  • #2
    Wild, I'm about to check one out tomorrow and probably buy it. I'm in Portland OR, so not terribly far away either. I might be interested but I'd have to figure out where to put the stuff... some spare parts would be nice


    • #3
      Hello, a newbie here...

      Has anyone taken you up on he offer of a service manual for the Conn "Artist" 720? I was about to pick up a "working" unit from a nearby church but was informed that after having moved it the seller (not an organist) was unable to make it work in the new location for a "hands-on" demo. I would like to read as much as possible about this model before I go to troubleshoot. I'm not an organist either, but I have had occasion to help restore a Hammond C-2 a few years ago. (I realize the Conn Artist 720 is not going to have much in common with the C-2, nor will there be as many parts available.)



      • #4
        You can probably get big money for the 6L6 power amplifiers, as well as the leslie, from a guitar guy.
        1914 Estey Parlor Organ. 196x Allen T-12a "Special" (MIDI VPO project). Digital piano. Various guitars. Autoharp. Banjo. Bowed saw. Musical Cat.


        • #5
          Hello again, and happy Independence Day!

          Even though I was unable to obtain a service manual for the 720 and knowing very little about the inner working of an organ, I went to have a look at the 720 mentioned in my redundant posts above (my apologies for that, I thought I was just editing my typo). It took me only about 2 minutes to figure out that a power cable had not been plugged into an outlet. Once plugged in everything seemed to play, so I rented a trailer and brought the organ home. Unfortunately, while I was getting the trailer, the organ was disconnected, wrapped with blankets, and attached to a dual-truck piano dolly. The tubes had been lightly taped in place with "gentle removal" masking tape at my request.

          When I got it home and unloaded I realized the connections had not been "dummy proofed" and I had no idea how I was to proceed. I did my best to hook it up properly after carefully removing the tape but was unable to get any sound.

          Here's what I've since learned (the hard way)...
          • The original amplification had been bypassed and the separate box I noticed had not been plugged in was actually a set of three Allen A-100 single input amps (I think... they're all stamped "905 1000" - the spaces for the second inputs each contained blanks). There was a bundle of wires going from the organ to the amps containing the aforementioned power cable and three speaker wires, each paired to a shielded cable with an RCA male end. The speaker wires appeared to be still connected to the internal speakers (including a functioning Leslie). I figured the RCA cables carried the organ's various outputs and all I had to do was connect them to Input 1 on each amp, attach the corresponding speaker wire to the screw terminals on that amp (marked with red and black), power on the amps and turn up the gain.
          • After getting no sound I feared I had somehow "killed" the organ. I decided to try connecting another source to the inputs of two of the amps and playing recorded music through the internal speakers. Nothing.
          • I then tried attaching a pair of bookshelf speakers to those two amps. Still nothing.
          • Next I connected a home stereo power amp to the internal speakers and signal wires. The amp went into thermal protection. It had been sitting for a while, so I tried a Crown XLS1000 pro amp, and it too went thermal.
          • I connected a pair of Yamaha stage monitors to the Crown amp and finally got some sound out of the organ.
          • I had pressed the circuit breaker on each Allen amp but that didn't help. I suspect whatever caused my other amps to go thermal may have blown (not visually accessible) fuses in the Allen amps.
          At this point I'm hoping someone can tell me what and how many fuses to buy, including where I might find them (before I dismount the amps to look at the undersides).

          I haven't yet examined the wiring going to the internal speakers to try to find the short. I will want to eliminate that before I try any amps again. Where shall I begin this task?

          Any help would be greatly appreciated. Please note, I'm not doing this for profit but to bless my widowed neighbor


          • #6
            The amps I have are like these but with only single inputs.