Ebay Classic organs

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  • myorgan
    commented on 's reply
    Vebo,

    Based on your last post, it appears you would like to close this thread to further postings and concentrate on the other thread. Please send me a Private Message if you'd like for me to re-open this thread.

    I'm glad your problem was solved, and that we could help.

    Michael

  • Vebo
    replied
    While complete updates can be found on the link in the above comment, just wanted to finish off this thread with the fact that the major issue was resolved - seems as though all the affected voices were going through the S-100 amp, and exercising the volume knob (marked Gain) brought the stops back to "normal" but the Tibias were still out of balance - too soft on ACC or too loud on SOLO. Adjusted Pots on the TG card for the SOLO Tibias turning down the Gain Pot, as it was maxed. This brought the SOLO Tibias in line with the ACC Tibias. This was mostly the focus of this thread. There are a couple of other things fixed, and a few annoying things I couldn't figure out how to fix, but if you're curious about that you can read the tail-end of the other thread.
    Last edited by Vebo; 12-02-2019, 06:53 AM.

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  • Vebo
    commented on 's reply
    Amplifier knob turned out to be the culprit. But please check out my other thread in the post below

  • Vebo
    replied
    Moving my updates on this topic to this thread

    I have had my ADC 3500 for a few months now, and a couple weeks ago, I lost proper functioning of 21 of my stops/voices – this issue is discussed in the following thread: https://organforum.com/forums/forum/electronic-organs-midi/theatre-electronic-organs/670176-i%E2%80%99m-devastated Likely culprit is suspected to be the EG

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  • Vebo
    commented on 's reply
    Ok, I pulled eg1 in slot 6. The affected voices were just barely hearable, just like before I pulled the card. I cleaned the contacts with alcohol, and reinserted it, still no change.

    What else might all these voices/stops have in common? I guess I'll proceed with pulling each card, cleaning contacts, and start exercising pots after noting position

  • jbird604
    replied
    As several have already suggested, open the cage and remove the EG-1 card in slot 6. The stops might then be at the correct level 100% of the time, and that would prove that the EG-1 is at fault. That one board is the only thing I see in the cage chart that is common to all the affected voices, at least with a casual look at it. There could be something else in common, such as the AP board, or some external device, such as a Trem generator or amplifier, but the EG-1 is a very likely suspect and easy to check. The organ will play without it, but the attacks and decays will be "Hammond-like" instead of pipe-like.

    You need to seek out and read all the threads on the forum about routine service on ADC organs. Your organ is 30 or 35 years old, and likely has never had the cage opened or any kind of serious maintenance. After all this time, there are pots with dead spots, sockets in the backplane could be corroded, and every RCA plug/jack union could be making poor contact. A good dose of Vaseline (or your favorite electronic cleaner/lubricant) will work wonders. Amplifier volume knobs may need to be sprayed with WD-40 or another solvent/lube and exercised to clean them up and make them reliable. You have quite a lot of potential work to do, but after routine maintenance, if there isn't anything truly wrong with a board, your organ will be as good as new.

    I totally understand how difficult it is to pull a big console away from the wall and do work behind it. I'm having the same trouble right now at my house!

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  • Vebo
    replied
    I think the temperature thing may be a red herring. Approximations: at power up, 30% volume of affected voices, 3 hours later, 50% volume, 4 hours later, 15% volume, 5 hours later, less than 10% volume. It’s been toasty in here since +1 hour.

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  • myorgan
    commented on 's reply
    P.S. Make sure the organ is OFF before you reinsert the cage card. Sorry, forgot to mention that.

    Michael

  • myorgan
    commented on 's reply
    Vebo,

    That cage chart makes me believe the EG-1 card in Slot #6 is the culprit. Try removing it and see what happens to the voices then. It turns out Larry may actually know what he's talking about–go figure!

    FYI, sometimes service people will use cold to diagnose solder intermittent issues. Your window may be doing the diagnosis for you. Let us know what the result is.

    Michael

  • Vebo
    commented on 's reply
    This information is PURE GOLD. I feel bad I declared tibias were alone the problem, I've been working on a simple piece, and trying to learn constraint in registration. With the panic that something seemed/is wrong with my new baby, I panicked rather than doing a proper check. I feel bad about wasting your energy with incorrect information, but: you managed to see beyond the misinformation, and in doing that, helped me start to understand how the system works. Thank you so much for patiently sharing your knowledge and time!

  • Vebo
    replied
    Today, the problem voices are back to low volume upon switching organ on. Am going to leave on for a while and see if I get my voices back again after it has thoroughly “warmed up.” Three more clues though:

    1. There is just enough volume on the affected voices that I can hear (I think) the attack in the sound envelope is markedly slow. Important because of what Larry said regarding the EGs above.

    2. This all started when the arctic blast hit (and the back of the organ is near a drafty window). You know, that Arctic Blast that’s in the news right now. Maybe that’s why it came back after being on all evening - it overcame being too cool (just guessing, it's around probably 60F near that window when heat goes lower during the workday and we are experiencing very cold conditions).

    3. I matched up the affected stops/voices with the cage chart. Note that the percussion stops on the ACC aren’t listed on the chart, so I had nothing to mark for them but they are also affected, but LOOK, a PATTERN! (DATA!) I'm still figuring out the chart, but all the affected stops are in the A row.

    Finally, I've resigned myself that I need to do the basic service and voicing jbird outlined in another post I found (https://organforum.com/forums/forum/...en-adc-voicing), but I'm going to make that a different thread, because regardless of what happens with this issue, that just needs to be a thread on its own.

    Click image for larger version  Name:	44B33992-D10B-45D4-94F7-7149B588BCA2.jpeg Views:	1 Size:	88.0 KB ID:	670433
    Last edited by Vebo; 11-12-2019, 05:12 PM.

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  • AllenAnalog
    commented on 's reply
    Dave, welcome to the Forum and thanks for posting. Based on reading the specs, your ADC-6500 looks like quite the nice instrument.

    While the "golden age" of Allen ADC-era instrument technical discussions on here seems to be winding down (witness the lack of responses to a more technical thread of mine on here) the availability of cage and external boards on ebay, Daffer, etc. is still quite good for these instruments.

    If a problem does not stem from a defective EPROM but some other component failure, you can still buy a used board and transfer your existing EPROM on the problem board to the replacement board. Some of the cage boards do not have EPROMs so that makes the exchange even easier.

    Worst case, dollar-wise, you can still get an exchange board from Allen through your dealer.

    Fortunately, some percentage of problems just come from pots that need exercise (don't we all?) and boards that are no longer making good contact with the cage edge connectors.

  • DaveADC6500
    replied
    Hello All,
    I have joined the group and can already see by Larry's post that this is a worthy investment.
    Larry's right. You have to stick with following the data that you have.
    I only have some block diagrams but it's been enough to get me through some times when I've lost half of the organ.

    I worry about the next time when I may need an IC instead of a bulb or pot exercise.
    Now that will be a real problem. But so far my ADC6500 is still going. Good luck Vebo
    Dave

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  • AllenAnalog
    replied
    Presuming your card cage has its front cover on and the cat did not pee on the vented top of the card cage, this continues to point to the EG card in slot 6. Once you can access the back of the organ the first thing I would do after taking off the cage cover is to pull the EG card in slot 6.

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  • Vebo
    replied
    Ok, Y'all are gonna think this Munchausen syndrome, but as another test, I left the organ powered up all evening. All the voices are back (right now). Next test, what happens after powering down and up again.

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