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Thread: Rodgers 702 not working

  1. #1
    ppp Pianississmo Dr Z's Avatar
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    Rodgers 702 not working

    There is a slight possibility that I may be coming upon a good deal on a Rodgers 702 and the accompanying PR300S. The organ was new about 15 years ago (when I played at this church) and was a wonderful replacement for the Baldwin predecessor. Sadly, it has only been played a few times in the past 5 years. I was recently told that the organ is not working. Also, the church is no longer interested in using the organ and they would like to utilize the organ niche for something else. Therefore it is unlikely that they will have it serviced - either for diagnostics or repair. A friend is on the Property and Space committee which will meet next week. He will try to find out the scoop as well as tell them that I'm interested in getting the organ - assuming that they don't want much for it and there's a good chance that I can get it playing for not much $$.

    I plan to visit the organ within the next few weeks and will take along some headphones (speakers have been disconnected). Does anyone have any suggestions on how I might do some basic diagnostics?

    1. Assuming that the organ powers up, lights come on, lighted stops turn on/off when pressed, pistons cause registrations to change might it be safe to assume that the problem lies in the sound-producing portion or amplifier?

    2. If it will play through the headphones, I'm thinking that the pre-amp is fine and the problem might be the main amplifier. I had a Yamaha Clavinova that quit after a lightning strike. All fuses I could find inside looked fine. Decided to try the headphone jack and it played, so I gave it away to a beginner. According to the 702 Owner's Manual I found online, there are L/R output jacks next to the headphone jack, so might I be able to connect it to a home stereo which should be satisfactory for basic practice?

    3. Somewhat unrelated question that should probably be posted in another thread: eventually, I would hope to interface it to my pipe organ control system to play my 13 ranks of pipes once I gather the energy to get the wind chests set back up. Is it difficult to tap into the key and stop switching? I would let the organ's own computer handle the pistons. This question might be important if I can't get sound via headphones.

    Thank you,
    Keith in Athens, GA.

  2. #2
    Moderator jbird604's Avatar
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    Keith,

    I replied to your post about the MIDI on a 702, though I had to admit that I was not fully up to speed on that subject. However, having seen and serviced a 702 and many other models of the same series (sometimes called "Cheetah" organs), I can tell you a few things to look at before you commit to this organ.

    #1 - keys. These organs used a keyboard built by Roland which was later found to have a fatal flaw. A pinkish epoxy was used to glue the metal weights up inside the hollow plastic keys, and that glue can fail over time, turning into a thick goo that slowly oozes out of the keys, letting the key weights fall out. The first symptom may be sticking keys. The weights come out still coated with enough of the goo to cling tightly to whatever they land on, and the oozing goo will get all over the piston rail and other parts. In short, it is a horrible mess and ruins the organ.

    For many years, Rodgers provided a replacement key action, but the supply of those has long been exhausted. AFAIK, they cannot be bought anywhere at any price. Some techs claim to have fixed them by soaking the keys in lye to remove all the epoxy, but I have not done this myself. At any rate, take a look underneath the keys and see if the pink goo is oozing out. If it is, that's much cause for pause.

    #2 - exploding capacitors. Many Rodgers models built during that era contained at least a few of the infamous silvery-blue 1000 mfd capacitors in one or more power supplies, or as final filter caps on certain boards, such as the four-channel pre-amp which is the audio processor in this model. These infamous caps were from a flawed batch of parts that were used over a period of years before the trouble was found. These caps tend to leak corrosive juice onto the circuit boards, and will sometimes catch fire and explode, making a cloud of stinky smoke and sometimes damaging the circuit board. To my knowledge, none have caused an actual fire in a building, because the fuel involved is very small. But they will of course disable the organ and require a repair that may be expensive.

    So......... look at the keys for the pink goo, and check the four-channel pre-amp board to see if it still has the silvery blue 1000 mfd caps. Either or both problems MAY have already been caught by a tech and taken care of long ago. Or maybe not.

    Beyond those issues, these organs have been quite durable and have a fantastic feature set and a great sound. You should look at the speakers. Some of them could have rotted foam surrounds on the woofer cones, but that is not nearly as big a problem, quite simple and cheap to fix.
    John
    ----------
    Church: Allen MDS-45 with Allen MIDI-DIVISION-II expander
    Home: Allen Renaissance R-230 with expanded four-channel audio and MIDI-DIVISION-II
    Shop: Bunch of organs in varying conditions, some good, some not...
    Half of an incredible two-man organ service team -- servicing all the major digitals in Arkansas churches
    https://www.facebook.com/pages/Birds...97551893588434

  3. #3
    ppp Pianississmo Dr Z's Avatar
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    John,
    Thank you for your reply. I don't think the organ has ever been serviced. A friend and I reconnected the speakers after we moved their locations. I remember at the bottom of the rear section there being two pairs of connectors - L/R Bass and L/R Treble. Also were knobs (I forget how many) to set the overall volume of the organ as well as to balance the Great and Swell to the sides. I sent the Great mostly to right and Swell mostly to left. That's all I remember from being inside the back of the console.

    1. So, from your description, I should look and feel over the underside of the overhanging portion of the key? If things are looking OK, I'm wondering if there's something I can do to prevent this problem from happening.

    2. Relative to where I would have connected the speakers, can you tell me where to look for these capacitors?

    I'm thinking that my first test will be to try headphones. If no sound comes, then I should probably pass on this. I already have 2 consoles that are OK for my pipe organ project. I was hoping that this would give me a currently functioning digital that I could practice until I get the pipes set up.

    Thanks,
    Keith

  4. #4
    Moderator jbird604's Avatar
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    You'll have to discern the condition of the keys. If they are not dripping glue, they probably don't have the bad epoxy, so you'd be ok. The four channel preamp board is the one with a set of 12 thumb pots, 4 orange to set levels of the four channels, 4 treble (yellow) and 4 bass (red). They are near the right edge as you look at the board from the rear.
    John
    ----------
    Church: Allen MDS-45 with Allen MIDI-DIVISION-II expander
    Home: Allen Renaissance R-230 with expanded four-channel audio and MIDI-DIVISION-II
    Shop: Bunch of organs in varying conditions, some good, some not...
    Half of an incredible two-man organ service team -- servicing all the major digitals in Arkansas churches
    https://www.facebook.com/pages/Birds...97551893588434

  5. #5
    pp Pianissimo baldwinc630's Avatar
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    Another thing that you can do is to look to see if there is a pipe interface in the organ. Some 602/702 organs had them provided just in case. If this organ has one, you may be in business. B630

    - - - Updated - - -

    I almost forgot. The keyboards, if they are not oozing out the glue, should be ok if not exposed to extreme temperatures. Also, on the audio side. This particular organ uses the STK-4192 stereo amplifier chip in its audio output modules. On some Rodgers organs, they are known to go bad by blowing the fuses on the module itself. Also, As JBird604 indicated, the audio pre-amp boards also go bad on occasion. I've had to replace both of these on a 580 which has a similar layout. Hope this will help. B630

  6. #6
    ppp Pianississmo Dr Z's Avatar
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    Thank you. I'll have to check on the pipe interface. I was pianist/organist at this church when the organ was purchased and even connected the speaker wires when the speakers were relocated.

    I haven't heard from my friend on the property and space committee of the church. If they decide to let me take it for a very low price, it might be worth it to pay a service person to check it out for me so I can find out exactly what's wrong and how much it will cost to repair it. The primary advantage of this particular organ is the hope that it will play in some capacity as a digital organ in order to let me practice regularly while I get my pipes set back up. Also, insofar as my MIDI question in another thread goes, Give me circuitry to tap into (MIDI or not) to connect to my Opus-II control system.

    Thanks again.

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