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Allen ADC Amplifier Module Repair

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  • #16
    Otay!

    Hooked up the amplifier, and at first the channel didn't work. Then, I cycled the organ off, then on again, and it came to life. When I tested the stops, however, they were still scratchy and intermittent. I went directly from the cage to the amplifier, and had the same result. So, now that I've ruled out the amplifier, it HAS TO BE the TG-6 board.

    So, I went to Daffer to see if they have a TG-6 board I could substitute in--they stop at the TG-5!!!X-( Anyone know where I could find a good, cheap TG-6 board to sub in for the one I have? I'm not up to the level of replacing the pots on the board (AA group), but I can certainly move the EPROMs from board to board. I have tried exercising the pots back and forth, but the effect isn't lasting--temporary at best, with the end result being 1/2 of the Choir not working.

    Ideas? Suggestions?

    Michael
    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

    Comment


    • #17
      Michael, I assume that you've done this, but if you haven't .... Before you go any further, pull a TG-6 board from a different slot in the organ (or from another organ). Make sure it's one that you know is working perfectly. Move the EPROM's from your defective choir TG-6 to this other TG-6, and then install it into the choir slot. Check to make sure that the choir stops are now working perfectly, and that they don't stop working after warming up. If this is the case, then put the EPROM's back on the original choir TG-6 and install it in the choir slot. Now check the stops, and if they are bad again, you can be sure it's really the TG-6 and not some extraneous factor.

      BUT, if the choir stops are still distorted and/or intermittent with a different TG-6 board in that slot, you have some other problem -- USAP, amp, speaker, or antiphonal relay. So this test will tell you once and for all if your TG-6 is indeed the problem.

      Try this repair before you give up on the board: Work a drop of WD-40 into each of the pots. Take the board out and turn it so the pots are facing upward. Put a bit of WD-40 on a Q-tip and work it into the pots right around the screwdriver adjustment slots. There is a minute gap between the movable part and the plastic housing, and just maybe a few molecules of the lubricant can seep into the pot. It might require several applications over a period of an hour or more to get some of the stuff into the moving parts. Turning the pot gently while applying the WD-40 might also help it get inside.

      When the lubricant finally gets to the carbon tracks, you will "feel" a difference in the way the pot turns. Exercise it gently but firmly, turning it back and forth many times before you put it back into the cage and try it out. This may not work, but it's worth a try, considering that you'll no doubt have to pay a thousand dollars or more for a new board from Allen.

      Also, I'd recommend testing your repaired amp by playing a complex signal such as the output of a CD player through it at high volume. If the sound is perfect, you can be pretty sure that the amp is OK (and the speaker connected to it). Don't overlook the antiphonal relays (if present) as a possible source of this intermittency and distortion. I've heard of several people having that problem with the relays, as the relay contacts inside the sealed plastic assemblies deteriorate over time and start to garble the sound. You can rule out the relay by simply wiring your speaker directly to the output terminals of the amp instead of to the relay assembly.
      Last edited by jbird604; 10-17-2016, 03:21 PM.
      John
      ----------
      *** 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!

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      • #18
        Originally posted by jbird604 View Post
        You can rule out the relay by simply wiring your speaker directly to the output terminals of the amp instead of to the relay assembly.
        John,

        I already bypassed and went directly from the cage to the amplifier--it did, indeed need repair on that module. Later this week, I'll try the other ideas you suggested to rescue the board & board swapping, as well as checking the antiphonal relay. Fortunately, I have a spare antiphonal relay board I can sub in, just to test the theory.

        Thanks so much for the detailed post.

        Michael
        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

        Comment


        • #19
          Ok. It will put my mind at ease to know that you have broken the problem down into all possible pieces. The only way to determine the faulty component is to isolate each of the links in the tone production chain.

          Are you saying that you ran an RCA cable directly from the cage output (the channel that keeps going out) directly to one of your amp inputs that you know to be good (one of the amp channels that works perfectly)? Doing that would tell you once and for all if there is a good clean signal coming out of the cage at that channel.

          If you can run that RCA cable from the choir cage output directly to any of your amps and get distortion or nothing at all, regardless of which amp and speaker you are connecting to, then your problem is either the TG-6 or the USAP board.

          BUT, if you get a good signal when playing that channel through some other amp/speaker combination, it means the trouble is NOT in the cage, but is either a bad amp module, a faulty antiphonal relay, a bad speaker wire, or a bad speaker.

          Just let me know how it turns out. I'm not going to sleep at night until I find out! (JK)
          Last edited by jbird604; 10-17-2016, 03:22 PM.
          John
          ----------
          *** 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!

          https://www.facebook.com/pages/Birds...97551893588434

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          • #20
            Michael,

            I just realized I've been saying the the "USAV" board could be involved in your audio issue. What I meant to say is that the "USAP" board could be involved. Obviously, the USAV board is concerned only with the Alterable Voices and has nothing to do with audio. The USAP (audio processor) board however could be the faulty link in the audio chain. Sorry about the confusion. Senior moment.

            - - - Updated - - -

            I just now re-read the last few posts, and I'm thinking you may have truly ruled out almost everything except the TG-6. However, to be absolutely positive, I do encourage you to pull a TG-6 from another slot, move the choir EPROM's to it, and test it in the choir slot. If all is perfect, then move the EPROM's back to the original choir TG-6 and put it in the slot. If the voices are now bad, you've certainly isolated the trouble to the TG-6 and nothing else.

            And once you have proven that it has to be the TG-6, I encourage you to try soaking some WD-40 into the pots and exercising the heck out of them. If that doesn't fix it, at least you've tried. And I'll get some sleep, maybe...
            John
            ----------
            *** 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!

            https://www.facebook.com/pages/Birds...97551893588434

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            • #21
              John,

              You can rest easy now. I discovered the issue. You were ABSOLUTELY RIGHT when you pointed me to the antiphonal relays. Just after church today (and before my wife had to leave for a performance), I had her help me swap the TG-6 boards, amplifiers, and speaker inputs to the antiphonal relays (she played the organ and turned it off and on--saves time).

              The antiphonal relay is the culprit. Only then did I notice that one or two of the relays had a date code stamped on them, where evidently they had been changed out before. Note the left-most relay card next to the handle of the screwdriver.Click image for larger version

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              So I changed all my general pistons so they add the Choir to Antiphonal, and also the Choir Main Off. John, can you tell if the following board could be substituted for the board that's in there?Click image for larger version

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ID:	600120I have performances coming up in the next week or two, so I really need to get things working. It also says to remove tape after cleaning--is there tape on that board I should remove?

              BTW, I found my soldering stuff. I called my wife while I was on the way to work one AM (around 6:45) and asked her where she hid it (I know--living dangerously). That night, she found the tool kit I had taken to the bedroom to fix a hallway light. It was in her way, so she'd kicked it under her vanity and promptly forgot about it!X-( Now I can fix the pedal reed switches, and the card reader light that went out.

              Michael
              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

              Comment


              • #22
                Good deal. Glad it was confined to one simple part. Probably just the relay contacts inside the plastic housing. These generic relays are available somewhere for not much money, so you can eventually repair that one if you get time.

                The one in your pic will certainly replace the old one. All Allen relays marked "Univrel" are operationally identical, except for the ones that were specially modified for the "bass softer" function. So just swap the new one for the old one, making sure to transfer the wires in the same order and to the same terminals. The terminals should be in exactly the same order on both relays.

                We should all make a mental note of the trouble that the antiphonal relays can cause. Yours is just one of several recent situations where the relay contacts had gone bad and caused a dead channel and/or distortion. I'm about to decide that I'll remove them from all the organs I service except for the very few that actually have antiphonal speakers connected to them. (Allen started including the relays by default at some point, whether or not the antiphonal speakers were ordered with an organ, so there are lots of organs out there with relays sitting there just waiting to cause the same trouble that you had, while performing no useful purpose whatsoever. Including the Allen in my own church.)

                Oh, and I have no idea about the tape that should be removed after cleaning. Never seen that before. If guess if the tape is still there it should be removed!
                John
                ----------
                *** 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!

                https://www.facebook.com/pages/Birds...97551893588434

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                • #23
                  Is that 6 conductor cable for the speakers I see in your photo? If so, what Allen dealer installed that system? That is a violation of the Allen prime directive:

                  "NEVER combine the outputs of two or more amps into a multiple conductor cable. Each amplifier should always have its own separate cable, and this rule should never be violated. If outputs are combined in a multiple conductor cable, such as 18-4 or more, oscillation can occur which can cause the amp to run abnormally warm, trip the circuit breaker, have high frequency squeal and possibly even damage the USAP-1 Audio Processor. "

                  td
                  Servicing electronic organs since 1969.

                  Comment


                  • #24
                    That's rather interesting to me. Was this edict something that came about with the later models of digital organs or have they had that proscription against multi-conductor cables forever? I'm wondering about the era of the earlier generation amplifiers (S-100 and predecessors)?

                    Back in the 90s when I was doing a lot of custom homes it was not unusual to use similar cable as shown in the photos for runs from power amps to stereo in-wall speakers. And the Johannus organ I recently acquired had a 100+ foot long factory-made cable with eight parallel wires (not 4 twisted pairs) for the four audio channels.
                    Larry is my name; Allen is an organ brand. Allen RMWTHEA.3 with RMI Electra-Piano; Allen 423-C+Gyro; Britson Opus OEM38; Steinway AR Duo-Art 7' grand piano, Mills Violano Virtuoso with MIDI; Hammond 9812H with roll player; Roland E-200; Mason&Hamlin AR Ampico grand piano, Allen ADC-5300-D with MIDI, Allen MADC-2110.

                    Comment


                    • #25
                      Originally posted by tucsondave View Post
                      Is that 6 conductor cable for the speakers I see in your photo? If so, what Allen dealer installed that system? That is a violation of the Allen prime directive:

                      "NEVER combine the outputs of two or more amps into a multiple conductor cable. Each amplifier should always have its own separate cable, and this rule should never be violated. If outputs are combined in a multiple conductor cable, such as 18-4 or more, oscillation can occur which can cause the amp to run abnormally warm, trip the circuit breaker, have high frequency squeal and possibly even damage the USAP-1 Audio Processor. "
                      Dave,

                      I won't throw the dealer under the bus--but I'd certainly like to!X-( There are so many things about this organ that were (IMHO) Mickey Mouse contraptions. And that's giving Mickey Mouse a bad name!
                      • The ADR was mounted on a panel that was swinging freely inside the organ as I brought it back home--only one screw holding the wooden door in place, and the anchor you tighten was swinging loosely just above the cage. It may have caused damage to the door just behind the cage, but I haven't found any.
                      • The 6-conductor cable is just one thing.
                      • The amplifier in question was affixed to the shelf from underneath, and the screws were dangling when I removed it. Not sure why they never screwed it in from the top.
                      So, after practicing all afternoon, I went in the house to get my wife's *Pad to make sure the organ is in tune for the upcoming performance. When I returned, this is what I heard:
                      • 161023_0012.mp3--This was me pressing Piston #1, and playing on the Choir, Great, and Swell
                      • 161023_0011.mp3--This was me trying to play with my first attempt. I tried full organ that time. The clicks you hear are me changing pistons.
                      I thought perhaps the *Pad was creating interference, so I turned off the Bluetooth and Wireless, and experienced the same issues. So I removed the *Pad from the situation, and experienced the same thing. A few times I turned off the organ for a few seconds, and then turned it back on, but it would only play for a split second before reverting to what is recorded above.

                      I wonder what happened? Overheating? The garage was only about 60ËšF, so I doubt it. I want to be sure it will play for the upcoming performance, or I will have to find another organ.

                      Thanks so far for all your help, Dave & John.

                      Michael

                      - - - Updated - - -

                      Originally posted by AllenAnalog View Post
                      That's rather interesting to me. Was this edict something that came about with the later models of digital organs or have they had that proscription against multi-conductor cables forever? I'm wondering about the era of the earlier generation amplifiers (S-100 and predecessors)?
                      That statement came from the Allen ADC Audio Manual. I'm not sure if it was ADC only, but all the other organs I have/maintain have a single pair per jacket. This is the first time I've seen 6-pair. I have a couple of Allen's original, brown-jacketed, single pair on a spool, so I can replace at least one pair from each of the 6-conductor to help eliminate the issue, to which Dave is referring.

                      Michael

                      P.S. For the recordings, I used my new Tascam DR-22WL I picked up in Florida in August. MUCH simpler recording organ now than before. I was hoping to get a nice recording, but instead ended up with what you hear above.
                      Attached Files
                      Last edited by myorgan; 02-16-2021, 08:23 PM. Reason: Remove whitespace.
                      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

                      Comment


                      • #26
                        Best guess -- cage power supply, or USCM supply. Test the cage supply to see if the voltages are correct and without AC on top of them. Same thing for the small 5 volt supply in the floor that runs the USCM.

                        All your ADC organs probably have the same USPS-3 cage supply, so you can swap one from another organ to verify that it is the problem.

                        It it's not the USPS-3, try the trick of popping out one USEG board at a time to see if the problem goes away. According to Allen, a malfunctioning EG board in the cage can cause problems for the whole organ, not just for the stops associated with that board. If you have a bad one, you might get one from Daffer or somewhere. Be sure to get the exact same number, EG-1, EG-2, EG-3, etc., as they are not interchangeable.

                        Beyond that, you might have to swap the USMA or the USKA from another organ. Worst case, swap the USCM. Do that last since it has so many connectors to pull off and so many screws holding it in place.


                        Oh, and the thing about multiple speaker wires in one sheath... Allen has been saying that for decades, but I've seen a number of Allen installs with wires bundled together, and haven't found any problems that it caused. Rodgers and Johannus, among other companies, don't seem to prohibit this. The dealers around here do it all the time.

                        - - - Updated - - -

                        Another thing that came to my head just now .... I surely hope it's not a backplane issue caused by a leaking USAV battery in the past. That is what sidelined our MDS for several weeks this past spring. But surely not.
                        John
                        ----------
                        *** 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!

                        https://www.facebook.com/pages/Birds...97551893588434

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                        • #27
                          Originally posted by jbird604 View Post
                          Best guess -- cage power supply, or USCM supply. Test the cage supply to see if the voltages are correct and without AC on top of them. Same thing for the small 5 volt supply in the floor that runs the USCM.
                          I'll have to take a look at that. The strange thing is that the organ has been fine for the past 2 years, but only first showed the issue today.
                          It it's not the USPS-3, try the trick of popping out one USEG board at a time to see if the problem goes away. According to Allen, a malfunctioning EG board in the cage can cause problems for the whole organ, not just for the stops associated with that board. If you have a bad one, you might get one from Daffer or somewhere. Be sure to get the exact same number, EG-1, EG-2, EG-3, etc., as they are not interchangeable.
                          I did switch the Swell TG-6 with the Choir TG-6, but did not change the EPROMS just to verify the Choir card was fine--it was. I made sure all the cards were seated properly after swapping them back, and the organ was fine at that point for a few hours.
                          Beyond that, you might have to swap the USMA or the USKA from another organ. Worst case, swap the USCM. Do that last since it has so many connectors to pull off and so many screws holding it in place.
                          I may need to swap those cards from one of the other organs. Running out of time, though.
                          Oh, and the thing about multiple speaker wires in one sheath... Allen has been saying that for decades, but I've seen a number of Allen installs with wires bundled together, and haven't found any problems that it caused. Rodgers and Johannus, among other companies, don't seem to prohibit this. The dealers around here do it all the time.
                          I've never had troubles with it before, but I'm not beyond splitting out the channels to make sure. This is the most likely culprit, in my mind, because it sounded like the MIDI adapter did on the ADC-4300 when I had it improperly grounded. I did add one of Allen's surge protectors. I wonder if it's not grounding the organ properly and causing the problem? I'll try removing it later this week to see if it solves the problem.
                          Another thing that came to my head just now .... I surely hope it's not a backplane issue caused by a leaking USAV battery in the past. That is what sidelined our MDS for several weeks this past spring. But surely not.
                          I doubt it's the backplane. When I got the organ, removing the AV batteries from the cage is one of the few things the dealer did right. Therefore, I don't think the backplane is compromised in any way. I haven't seen any damage, at least.

                          Thanks so much for the information. I'm hoping one of these possibilities will solve the issue. It can certainly not cause more damage. I am hoping the problem can easily be sorted out. Thanks for all your help.

                          Michael
                          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

                          Comment


                          • #28
                            Michael, note that I mentioned popping out the USEG boards one at a time. This is an old service trick that Allen taught us a long time ago. Their engineers discovered that a single faulty USEG board in a cage could disrupt the operation of the entire system, not just the particular voices that are driven by that board. So they taught us this troubleshooting trick.

                            You can do this without turning the organ off while popping out EG boards, but the organ MUST be turned off before you start putting them back in place. This applies ONLY to the USEG boards, NOT to TG, FG, or any other boards in the cage.

                            With the organ turned on and malfunctioning, pop out the first USEG board in the cage, starting at the left. Just pull it out smartly with the two white lever/tabs, all in one quick motion. Do NOT put it back in, just pop it out and then try the organ to see if that fixed it. If not, move on down the line (leaving the first board popped out -- remember NOT to put it back in place with the organ powered up!). Pop out the next EG board and try the organ, etc.

                            This may not prove fruitful, but if it does, you can put all the EG boards back in place except for the one that finally stopped the issue. That is the bad one. Now you can check it over, pull out the EPROM and clean the legs, look for any obvious defect, put some Vaseline on the card edge before re-inserting it.

                            With EG boards removed, stops affected by each board will no longer have appropriate attack and decay, but will just be "on and off" like Hammond organ sounds. Percussion and sustain will be disabled. So you don't want to play an organ like this, but it is a good troubleshooting tool. At least you can rule out these boards, given that they have a history of causing trouble.

                            BTW, the multi-wire speaker cable wouldn't cause this kind of trouble. The thing that Allen feared about using that kind of speaker wire was amplifier oscillation -- they thought one amp might start feeding high frequency signals into another amp by some kind of capacitive coupling inside these wire bundles, and that on-going feedback might cause an amp to oscillate a high frequencies and thus overheat or burn itself up. It wouldn't cause the whole cage to go bonkers like yours has done!
                            John
                            ----------
                            *** 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!

                            https://www.facebook.com/pages/Birds...97551893588434

                            Comment


                            • #29
                              Originally posted by jbird604 View Post
                              Michael, note that I mentioned popping out the USEG boards one at a time. This is an old service trick that Allen taught us a long time ago. Their engineers discovered that a single faulty USEG board in a cage could disrupt the operation of the entire system, not just the particular voices that are driven by that board. So they taught us this troubleshooting trick.
                              Thank you, John.

                              I remember when I pulled the Swell TG-6 board, thinking it pulled fairly hard. If it's just an EG card, can I "borrow" one from the Symphony's organ (ADC-6000), and will it work just as well in the organ I have at home (ADC-5400)? It will be Wednesday before I get a chance to try it, but I'll keep you posted then.

                              Thanks again for the hint.

                              Michael
                              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

                              Comment


                              • #30
                                If that TG-6 card was a bit hard to pull, it might indicate some degree of corrosion or "freeze-up" in the sockets themselves, which could in fact the cause of your current problem. Before doing anything else, I'd pull each board individually and do the Vaseline thing, and also carefully re-seat each EPROM while the board is out. That just might solve your problem.

                                You can of course borrow any board you need from one of your other ADC organs, provided it is EXACTLY the same. USEG-1 cannot be interchanged with USEG-2 or any other number. Same with all the boards, though having a letter "A" or "B" after the number only means that it is an improved or updated version, and it will interchange.

                                If you borrow a board from another organ and there are EPROM's on it, do swap the EPROM's so the properly characteristics of your 5400 will be preserved.
                                John
                                ----------
                                *** 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!

                                https://www.facebook.com/pages/Birds...97551893588434

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