Allen ADC 220 short sustain and reverb issues

[Matt Philaya]

CONTEXT - I am a pastor, and our church received a 1985 ADC 220 in good condition. We have a much larger Allen in the sanctuary, and in our small rural community in southwestern Minnesota, church organists are quickly becoming rare. This 220 needed a home, and we aquired it to provide our pianists a less intimidating instrument on which to learn and build confidence in order to play the much larger organ for worship.
ISSUE - Overall, this 220 works fine, but the 'short sustain' and 'reverb' features do not appear to work. Upon opening the back, I see that there is a reverb unit installed. Should simply flipping the reverb and/or short sustain tabs provide the effect, or is there another combination of settings? Also, are there some simple ways to troubleshoot the reverb unit in case that's the problem? It sounds okay without reverb, but I would like to see if I can get at least the reverb if not also the short sustain to work.
Thanks

[jbird604]

The reverb should activate when you flip the tab. It's possible that the reverb tank has gone bad, or that the electronics on the audio processor board that send to and receive from the reverb spring have gone bad.

Another possibility is that the RCA audio connectors are not making good contact. On organs of that age, it is always good practice to pull the RCA plugs out of the jacks (gently but firmly), use your finger tips to rub on a tiny film of Vaseline on the pin of the plug and on the shoulder of the jack. This will remove corrosion and restore good contact. This ought to be done to EVERY RCA plug/jack in the entire organ system.

Finally, there is a reverb level adjustment on the audio processor board. You need a very small miniature flat screwdriver to turn it. It may be turned all the way down, or it may be sitting in a dead spot and will return to life if you just "exercise" the pot a few times back and forth.

Please note that the "short sustain" tab by itself does not cause any sustain to happen. It merely causes the normal sustain on the chimes (if you have chimes) or on the percussion tab to become shorter when engaged.

[Larrytow]

Pastor Matt, welcome to the forum. Jbird gave you good advice as usual, so I have nothing to add.

I'm really posting to tell you that I think it is a Wonderful idea to have another organ at your church for your pianists to learn to play the organ on ! So many churches just give up trying to find an organist, and here you are trying to make your own organists. That is really a great idea. Once they get comfortable with a smaller organ, they will Want to explore the resources of your larger Allen.

And of course curious organists here ( speaking for myself, anyhow ) would be interested in knowing which other Allen you have there.

Keep us posted as to your findings on the 220. Plenty of helpful advice here, should you need more.

[Matt Philaya]

Thank you! This was very helpful and it did get the reverb to work.

I’m not used to posting to forums, just reading, so I hope this appears where it’s supposed to.
The model of our larger Allen is something I’ll check into.
Taking in this 220 as a practice instrument at our church was also the best excuse our regular organist and I could come up with to justify having it. It turned out to be a well received idea. One of our pianists came to the church last night, and I ran through the basics with her on how to use it. She kept remarking “Oh, so THAT’S how that works!” She then stayed for a while to try some hymns on it, which is exactly what I hoped would happen. She’s never dared touch the one in the sanctuary because I suppose it seems like the cockpit of a commercial jet.
This morning I opened the back of the 220, having first done my research, and carefully put Vaseline on all of the RCA jacks I could find. I then found the adjustment for the reverb, and turned that up. I discovered that when on, the reverb hums. I set the volumes to 7 (where they originally were), and that helped. I also found that the PROJ PRES tab now worked as it was supposed to, with a faint crackle, that seemed to disappear.
I should that that I’m not an “organist”, but I have a music background and am mechanically inclined, so I know just enough to try out the instrument, troubleshoot and repair small problems, and also when to quit before I break something.
That said, the inside of this 220 could use a good dusting. I vacuumed the inside staying away from any circuit boards and sensitive parts. The dust I would like to remove is between the keys and on the wood and contacts of the keys, as well as the contacts of the tabs. I certainly didn’t want to vacuum it or touch it. I figured a can of compressed air might work, but what do you do with all the dust that would blow around? I would prefer to leave it, although I wonder if dusting this is an important maintenance routine.

[myorgan]

All,

Do the ADC-220 keyboards lift up like the other ADC and MOS keyboards? If so, it would probably be more effective to clean them that way.

Michael

[jbird604]

You can certainly vacuum the keyboards and even the key contact switches (gently, with a brush attachment). The contact switches are heavy-duty industrial leaf switches, so you're not going to break them. If one of them ever fails due to dust on the contact points, the "hundred dollar bill" method works well. Take a clean hundred dollar bill, insert it between the two leaves of the switch, push the key down enough to close the switch, and pull the dollar bill back and forth a few times to polish the points.

If you don't have a hundred dollar bill handy, a regular $1 bill works just as well ;-)

To get to the keyboards easily, raise the top lid, remove the screws that hold the stop rail in place and set it aside (it has a very long pigtail, though you might have to release the pigtail from a wire tie.) The swell keyboard will simply lift up I think. It's possible for it to be anchored with a screw in the side, but usually not. Then you can see the contacts of the great keyboard to clean them as well.

The stop tabs are simple open switches and they sometimes get gunked up with a black tarry deposit. You can clean them with a Q-tip dipped in alcohol or WD-40 or other solvent or light lubricant.

The rest of the console interior can be safely vacuumed, but be cautious around all circuit boards, as the chips can be static sensitive, and a vacuum cleaner is a notorious source of static electricity.

The hum in the reverb might be due to a ground connection still not making good contact. Did you clean the RCA plugs and jacks on the reverb spring tank itself?

[Matt Philaya]

I found out our sanctuary organ is a 2006 Allen Quantum 275 with back rest and pull out stops. Before Easter our only organist broke her right wrist tripping on cords in the loft. Bless her heart, she played through Holy Week and then got a cast. She's out for six weeks and the organ is silent. It did raise awareness that we really need more people to play.