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Allen Organ problems

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  • Allen Organ problems

    Our church has an Allen organ that I donated several years ago. I'm the church organist so I'm the only one who plays it, the organ has suddenly developed an issue, the volume all of a sudden just drops. Then it increases to normal then immediately drops again. This happens on both the preset stops and also the manual stops. You can hear a crackling raspy sound in the speakers. I love that Allen. I hope it's not going to be a serious problem, I've done some checking on it, and have been told the contacts need cleaning. The organ is from 1981, it's a 2 manual digital computer organ. What could be wrong? Sorry I don't have a picture of it. Thanks for your help.
    Nathan L Thomas

  • #2
    Yeah, in the back of a MOS organ is one volume dropper chassis or possibly two. They have a cable coming from the power amp (s) and are typically mounted on the side. Another cable goes out to the main or antiphonal speaker. The chassis has a relay and a power resistor stuck straight up from the chassis, with a sliding tap on it (when unscrewed) to change the volume.
    With the power off for some time, take an auto points file (hard to find these days). or a nailfile and stick under the relay arm at the end where the bumps are and file the oxide off a little. You may need to take a plastic cover off.
    Do not use emery cloth or sandpaper, it can embed insulating sand in the surface and cause more problems later.
    This could also be a dirty wiper on the volume pot on the amp, but start with the chassis after the amp. It is easier to get to.
    city Hammond H-182 organ (2 ea),A100,10-82 TC, Wurlitzer 4500, Schober Recital Organ, Steinway 40" console , Sohmer 39" pianos, Ensoniq EPS, ; country Hammond H112


    • #3
      Dirty key contacts will not cause that issue.
      A model number would be helpful. 1981 would be a MOS 2 series.

      Does the volume drop out completely or just get soft?
      Does it happen on all voices? All speakers? are speakers internal, external or both?
      If it's on both channels that eliminates amps.

      Reseating all plugs and plugin circuit boards would be the first step.
      Next would be measure power supply voltages when the volume is low.

      Servicing electronic organs since 1969.


      • #4
        I would add that an Allen organ from 1981 is not an "old" organ at all. Plenty of Allens going back to 1971 are still in use around here, and a few of the analogs that are even older than that. So it's not time to replace it or panic about it become obsolete or crippled with unfixable problems. A newer organ would have some nice features, but unless you are unhappy with the sound you should stick with it.

        While it's not yet an old organ, unless it has been getting an occasional service call, it is long past due for some serious routine maintenance. Sockets where the boards plug in, RCA audio plugs and jacks, terminal strips, and other points where electricity must jump from one metal part to another -- all these points are subject to become intermittent. Good maintenance involves taking them apart one at a time, gently cleaning as needed, applying a bit of light lubricant, and re-assembling firmly so as to assure a reliable connection at each point. Power supply voltages can drift and need to be regulated. Pots, wherever they are found, become sketchy after all those years and need to be "exercised" and sometimes lubricated or even replaced.

        Do get the info Dave mentioned above -- model number, internal or external speakers, a more specific description of just what happens. With more information, there are several of us on the forum who have a lot of experience with Allen digitals, and we can possibly diagnose the trouble from here.

        Just a wild guess -- you are probably losing just one of the audio channels intermittently. When that channel goes out, the impression is that the volume of the organ drops greatly. One very likely cause is the volume control knob on the amplifier. There should be at least two Allen S-100 amplifiers in the console (or they may be on a rack if this is a larger instrument). The volume control knob can be rotated back and forth through its full range about a dozen or so times to "clean" its wiper. Do this with each amp, then reset the knob about where it was before you started. This might be all the cure you need right now, but remember that routine maintenance is still needed.
        *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!


        • #5
          I tried all the preset stops as well as some of the manual stops. When I noticed the volume drop it's when I want to play hymns, when I increase the volume pedal for the hymns it just drops and gets real soft, then makes static noise in the speakers. The organ has 4 external speakers. It's sounding like something to do with the volume pedal, is it hard to get the innards of the organ? I'm not very much mechanically inclined, so may have to call an organ service man. I'm not sure of the model number, seems like it's a 300 series but I may be wrong.


          • #6
            It acts up when you increase the volume. It starts making static noise.

            Could it be as simple as the potentiometer in the Swell pedal is making intermittent contact?

            Bach On
            Make being happy a way of traveling, not just a destination.

            Church organ - 2 manual 12 rank Estey Pipe Organ with 12 Artisan Digital Stops
            Home organ - Allen R-230 organ (We also have 48 pipes in a facade)
            We have a Yamaha 6' 8" Grand
            Have used an older Korg T3 keyboard and MIDI for doing musical arrangements.
            I'm a Methodist organist.
            I taught high school chorus, elementary music and middle school music.
            Became a Technology Specialist.
            Retired from Education after 32 years.


            • #7
              My Allen organ sometimes does the same thing. Good thing it's not played in public.


              • #8
                Originally posted by Bach-On View Post
                It acts up when you increase the volume. It starts making static noise.

                Could it be as simple as the potentiometer in the Swell pedal is making intermittent contact?

                Bach On
                Uh-uh. Expression uses a lamp and a light-dependent resistor.


                • #9
                  It did that at church today, fortunately I go to a small church that's mostly elderly folks but the sudden drop and static sound is embarrassing to say the least especially when you're wanting to increase the volume so we can sing the hymns. So today I just shut it down and played the piano. I hope to have it serviced soon, from price quotes there's a local organ service man that quoted me about $250-500.00 to fix it. It is worth it to fix it as you can't beat an Allen for true pipe organ sound. We are a small church, located in Tulia, Texas.


                  • #10

                    First of all, welcome to the Forum. To find the model number of the organ, you don't need to be too technical. Just lift the lid from the front, and pivot it toward the back. There is a chain on the right-hand side of the organ that will keep the organ lid from going too far back. On the left-hand side of the back rail, there should be a metal tag with the patent codes, serial number, and model number on it.

                    No tools are needed to get inside the back of the organ. To remove the back panel of the organ and get access to the innards, you'll just need to rotate the 2 wing nuts at either end of the back rail, and the back of the organ will tip outward. There are 3 or 4 metal clips on the bottom, holding it flush, and after you've tipped it outward approximately 3-4", you can lift an inch or two to completely remove the panel and set it aside.

                    If you have a camera, could you take some photos and post them? That will help members to be able to guide you concerning where to look to diagnose what is going wrong with the organ. If you have the means to record the anomaly, you could also post that so we could hear it.

                    We look forward to helping you and finding out what is wrong. The fix could be significantly less than the cost of a repair person.

                    Way too many organs to list, but I do have 5 Allens:
                    • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
                    • Lowrey Heritage (DSO-1)
                    • 11 Pump Organs, 1 Pipe Organ & 7 Pianos


                    • #11
                      Hi Michael and all other organ posters. To see a picture of the organ go to Google search, type in "electrolux-dude", then click on images. My picture will be the first one, it was taken a couple of years ago at church, in the summer, it gets very hot in Texas in the summer so the picture is of me sitting at the Organ at the console, you can see 2 of the 4 external speakers of the organ. The model MOS 505-B sounds like it might be right, I do remember that it has B in its model number. I do not know how to get that picture to transfer over to the forum but if you will do a Google search of electrolux-dude and images you will be able to see the picture. I am wearing shorts as it gets very hot here in the summer.


                      • #12
                        I can't tell the cabinet style for sure since the flowers are in the way but it might have the model number under the keyboard shelf about where your knees are.

                        I don't think the 505 had preset pistons.
                        If a MOS 2 then maybe 124 or 224? Jbird? Jbird? Bueller?

                        Last edited by tucsondave; 03-22-2015, 07:58 AM.
                        Servicing electronic organs since 1969.


                        • #13
                          Yeah I don't know for sure the model number but I do know it is under the keyboard. I will look next time when I am going to church. I guess to make a long story short I found the organ in a local thrift store, they had $675 marked on it and I told them I wanted to buy it for our church and they let me have it for $300.00. When I bought it I contacted Allen with the model and serial numbers and they told me it was installed at a church in Vega, TX in 1981. Anyway I'll try to get some better pics posted and a model and serial number.


                          • #14
                            I do love a mystery and should have been a detective. Here's what I can surmise from your pic (it appeared just as you said it would).

                            The Allen "contemporary" (spaceship) console dates it to between 1971 and 1985, and since it has 5 presets and a "0" piston, and has no tabs in a separate "general" section, it can't be an ADC model and (thankfully) not an MDC model either, so it's some variety of MOS organ. I see that it has the folding top in place of a roll-top cover. IIRC, the folding top had been completely retired before MOS-2 organs came along, making this one a MOS-1 model.

                            It looks to me like it has brown grille cloth on the kneeboard instead of solid wood, so that would make it one of the 100 series models, of which there are several. Some models have presets and others have DM or Sequential capture. Yours has presets.

                            Could be a 120 or a 124, both of which have 5 preset pistons and grille cloth. There was also a model 182 sold only to LDS churches that would also match the pic. Your remote speakers are of the "Monitor II" type, which would add weight to my guess that it's a 100 series. The 200 series and larger organs were sold with either HC-xx speakers or with the bigger 16-1 and 32A/B speaker cabinets.

                            So, I'm guessing it's a 120, given the folding top lid. All the sleuthing aside, we need to discover why the audio cuts out when you try to increase it with the expression pedal.

                            Since the expression in all Allen digital organs is by a lamp and photocell, there is no expression pot to get dirty, and it would be highly unusual for any kind of mechanical malfunction to affect the expression shutter. Since you also get a crackling noise when this happens, that also turns the attention away from the expression pedal itself.

                            Once or twice I've known the physical movement of the pedal to cause something else in the organ to move -- perhaps a wire has come loose from somewhere and is touching the back of the pedal when it is pushed forward. That's a remote possibility, but something to look for.

                            Also, the expression lamp brightness control is by means of a slider resistor that is mounted right below the expression pedal. Check to see if the motion of the pedal is somehow affecting that little unit. I suppose it's possible for the sliding part of it to become loose and somehow create some electronic noise that gets into the system.

                            However, I'm more convinced that you have some kind of amplifier issue. It may be nothing more than a poor connection where one of the RCA plugs goes into the amplifier. Or something like a loose screw on one of the speaker terminals. A worse thing would be an electronic problem inside the amp, such as a bad transistor or other component.

                            To look inside the "contemporary" Allen console, unlike all other Allens, you only have to remove two screws that are holding the wooden panel in place, then it will tilt outward and you can lift it off. In the floor of the console you will probably see two amplifiers, and they will be quite distinctive, with large transformers and capacitors on top and with three RCA plugs connected to each one close to the volume control knob (which may not be a knob, but just the shaft of a volume control sticking out of the chassis).

                            It won't hurt to try a little simple maintenance on the amps. Remove each RCA plug individually, then re-insert it with a very small twist so it will clean its connection points as it goes back in. After doing this, sweep each volume knob through its range several times then put it back where it was when you started. (There may be a red mark to help you put it back.) Also look at the screw terminals where the speakers connect and make sure they are tight. Look at the terminal strip, if present, to which the external speakers are connected, and make sure all the screws are tight and that there are no short circuits between any terminals.

                            Look at the expression pedal and make sure that it doesn't bump into anything when it is moved.

                            There are other things you can do if you're up to it, such as regulating all the power supply voltages, checking for AC on the DC supplies, cleaning and tightening up all the connectors in the system. But these may be best left to a tech, if the simple amp maintenance doesn't do the trick.

                            Good luck!
                            *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!



                            • #15
                              Did you take the back off and take a nailfile to the points on the volume relay on that little chassis? The one controlled by the echo tab, on the 301 I worked on. It is about a 5 minute job.
                              It would be a shame to spend $500 to get a 5 minute job done professionally. Wiggling the volume pot on the amp or amps is a very cheap maintenance procedure, too. That would be the one minute job, too, once you had the back off. The back of the 301 I worked on had two screws, I think they were phillips but take a 6 way screwdriver, or at least a phillips and a flat blade screwdriver. Removing and replacing any RCA plugs is very quick, as is making sure the screws on the cables from the amp to the little volume drop relay chassis, and the cables from that chassis to the speaker, are screwed tight.
                              Make sure the power is off before you take the back cover off.
                              You could also have wiring problems from the volume drop relay chassis to the speaker, in the wall somewhere, but that is a more complicated job. If the wiring was installed by amateurs, poor quality connections may have resulted. Wire nuts are not very good on speaker wiring, I'd use crimp connectors like butt splices at least, on any connections additional to the speaker screws and the volume drop relay chassis screws.
                              city Hammond H-182 organ (2 ea),A100,10-82 TC, Wurlitzer 4500, Schober Recital Organ, Steinway 40" console , Sohmer 39" pianos, Ensoniq EPS, ; country Hammond H112