Conn 653 theater organ issue

[Kingkeys]

Hi all
Well I am at it again!!! I have a chance to pick up a beautiful Conn 653 Theater organ for free. the only thing there are some issues The dude stated "The organ has sound but it hums and a whole bunch of sounds comes on in once as if its haunted. I had this problem and had changed a bunch of capacitors that made it work fine for years." So can anyone help with this should I pick up the Conn and try to fix it? Or just let it go to someone else?
thanks all jr Kingkeys

[andyg]

I'd be inclined to let it go. This one uses multiplex keying and if those circuits go bad then you can get those symptoms. No replacement ICs available IIRC. Hums could well be capacitors but if they were changed already, then they shouldn't have gone bad this quickly.

Free is always good, though. And it would be a perfect candidate for gutting into a 3 manual virtual organ console. Depends how much it's going to cost to shift it and how much work you're prepared to put into it.

[jbird604]

Good advice from Andy. I too would say that the console itself is quite awesome and would make an unsurpassed basis for a VPO. The 653 was the final iteration of the 3m Conn AGO theater series, of course, with extreme "Kimballization" -- the revered Conn multiple oscillator system augmented with those deliciously synthetic Kimball solo sounds of extraordinary variety.

As Andy notes, the system stands on the multiplexer foundation Conn had introduced in the precursor model, the 652, and also employed in a few other models toward the end of production. Notably the 717 classical model. This very flexible digital control system replaced the vast number of separate key contact wires that had always been underneath the keyboards on large Conn organs prior to this, thus getting rid of one of the most troublesome aspects of the Conn organ -- the sketchy, erratic keying of the "pulse" voices (strings and reeds). With the digital control system, all pitches of all stops were keyed with a competent solid-state circuitry, free from the static and irregular volumes, cutting in and out, and so on that had plagued Conns up until them.

So what's not to like about it? Well, the multiplexer system was a fine idea, but apparently the construction methods were not top-notch. Nearly every one of these organs eventually develops cracked solder joints throughout the long motherboards (located on the keydesk shelf, right underneath the keyboards. Each motherboard has a number of sockets into which are plugged the individual keying boards for all those separately generated notes in each rank. Each keyer board has a card-edge connector with about 20 or so contact points on it, and thus about 20 or so solder joints under the socket, going into the motherboard. For some reason, possibly the insufficient amount of solder applied in the manufacturing process, these solder joints tend to open up with time, producing all kinds of weird keying malfunctions and noises. No doubt the huge sound the seller described.

Other weakness of the system are found in the push-on connectors in various locations. A problem I ran into a few years back on a 652 was that the pedal generator system (a fully digital synthesizer) developed a bug that made it untunable, and we failed to fix it, despite changing out many of the components on the board. And the parts are NLA from anywhere in the world, AFAIK.

Thus, these once-fabulous organs are usually shot through with troubles. Maybe fixable with extreme amounts of TLC and diligent hand-work, but you gotta really love one to put that much effort into it.

But the keys, pedals, casework, and other hardware are quite excellent and would certainly be worth salvaging and turning into a magnificent theater VPO.

Free is good, but happens to be about what it's worth. As Andy notes, the cost of getting it moved may be the deciding factor.

[Kingkeys]

Well i just got off the phone with the person and she said the organ is working fine .Do you both think it is dirty contacts? the person stated that it takes 5 minuets for the crescendo to warm up ? what is up with that? but she said everything is working fine now no issues.here is a picture. look good maybe I will midi the keyboards

[andyg]

It doesn't need to 'warm up', it's 100% solid state. So we know that it hums, has keying issues and has to warm up, but is 'working fine'. I smell a rat!

Good for gutting as it is a lovely AGO spec console. Go get it if the moving costs are OK and you have the space, and then see what you've got.

[Kingkeys]

She still has the organ on and everything is working perfectly I going to take a gamble and pick it up myself I know the monster weighs 500+ lbs. i keep saying for nothing. don't the console look like it is in excellent shape? maybe I can clean all the connector pins if this problem is intermittent.

[jbird604]

It is a pretty thing for sure! But keep in mind that the erratic keying is NOT due to dirty contacts! It is due to the lousy soldering and cracked joints in the keyer motherboards. If most of it in fact seems to be working, you may be able to cure the rest of it with judicious re-working of the motherboards.

I'd start with a THOROUGH diagnostic process. Keep in mind that while it may seem superficially ok, don't be surprised if once you start checking it out you discover all kinds of irregularities. You'll have to turn on each stop one at a time, and play every note of every stop up and down the keyboard to truly ascertain its condition. Also be sure that it makes NO sound at all with all the stops turned off and presets canceled.

A little old man here loves "organ music" (he says), but of course he isn't a musician of any kind, just sentimental about hearing an "organ" played in church when he was younger, whatever it may have been.

Anyway, he loves to pick up "free" organs and "donate" them to churches. He often comes by the shop with an old organ in the back of his truck and wants it checked out before he gives it away. He'll tell me that it seems to work, because "It makes some kind of a racket on every one of them keys!" That's his definition of a "working organ." Needless to say, such an organ is often far from "working" from a musical point of view!

Anyway, good luck. If it can be fixed, it fan once again be a fabulous machine. If not, then it will make a lovely base for a MIDI VPO.

[Kingkeys]

How can i purchase a MIDI VPO. DO you have any info and Pricing on the unit Do I have to remove all the stop tabs like I seen on youtube? Do you know where I can get a service manual for the Conn 653 I don't know where the keyer motherboards are. OH also I noticed the organ has a 10" Leslie speaker .Does it have a 11 pin Connector that I can hook up a Leslie 720? I have 3 of them. thanks for all your help You and Andy are the best "HOWS BETTA THAN YOU"

[jbird604]

Now I'm out of my league! You will have to do some googling and reading in various places to find out about doing a VPO setup. There are certainly individuals and companies out there that can sell you a turn-key VPO setup, or you can take the path that many hobbyists have, building your own from scratch. Whether or not you can use the existing stop tabs and other controls will depend on the details of your VPO system. I do know that some who have built a VPO have fully integrated it into the existing console controls, which certainly looks nicer than having to place a touch-screen monitor on the console. But again, that's out of my league.

The small company called "Organ Service Corporation" up in Merango Indiana that provided support and parts for Conn for decades has recently folded up completely. That was, to my knowledge, the only official place to buy Conn service manuals. Nowadays they are often for sale on ebay, so you might keep an eye open for one there.

We have some Conn organ experts on this forum who might be able to direct you. As to the motherboards, you can't miss them if you raise the keyboards. They are mounted flat on the keydesk and right in the open once you swing up the manuals.

To do that on a typical Conn, you raise the top lid, swing up the stop rail, then simply fold up the manuals starting with the top one. They may be latched to one another with snap catches, and it's possible that you have to slide them forward a bit to swing them upward. It's been quite a while since I was inside a big one like the 653. Again, maybe one of the real experts will weigh in now.

Good luck! Please post pics and update us on your progress. Have fun!

[Kingkeys]

Thanks Brother I will do that when I get the Organ. What happened Conn Hired techs that don't know how to solder? what happened? now when I take off the keyer motherboards are they PC boards single side or double sided?. What year did the Conn 653 hit the market? OH also I noticed the organ has a 10" Leslie speaker .Does it have a 11 pin Connector that I can hook up a Leslie 720? Thanks again

[jbird604]

The 653 probably came out in the early 80's, soon after Conn was bought by Kimball. The soldering of the motherboards was probably done using the automated technology that had just come into use at the time, and there were in fact other organ companies whose products have suffered the same issues. I don't know just how that automated soldering worked, but it evidently didn't put a thick enough coat of solder on the joints, and many of them broke down in time.

The boards are probably single-sided. I know this was before double-sided boards became common. The little individual keyer boards just pull up straight out of their sockets, and they are all identical, I think. so you just remove them, disconnect the jumper wires that join all the motherboards together in a daisy chain, then you can unscrew them and flip them over for re-soldering.

I don't know what kind of Leslie speaker the 653 was designed for. I know that a Leslie cabinet was an option with many Conn models, so I assume the 653 will have a standard round Leslie socket of some kind.

[twnelson]

The 653 came out in 1980, shortly after Conn was acquired by Kimball.

The main problem with the solder joints was that the quality of the pin part of the connector was crap, in that any plating or tinning that would have inhibited corrosion before PCB assembly was poor to non-existent by that time in the company's history. The engineers that I knew at Conn were really frustrated that they were cutting corners in that manner because they knew what the problems would be: incomplete, crystallized wave solder joints due to oxidation on the pins that would eventually fail. This actually started showing up on some models as early as 1976 where they were trying to cut production costs on new models.

The keyboard bus bars on the digitally-keyed model actually consist of 12 key segments that are scanned in a matrix by the LSI circuitry. Not ideal for the typical x8 matrix commonly used these days by MIDI converters. The one I helped convert (a surge-damaged 652) we connected all the segments together and used a 61-note input interface.

[Jay999]

You can probably restore that 653 by heating up all the plug connection pins, and scrape the legs of all the chips. If you are good with a soldering iron, it helps too. I did that to a couple of the 653's lesser cousins....a 635 Caribe and a 644 Martinique...both 2 manual instruments with the same kind of circuitry as the 653.

It's not difficult work, but it does take quite a bit of time and patience to go through each and every board in the organ. Rather than two sided boards, this organ has a few mother and daughter boards, where the daughter is mounted on top of the mother board.

When I scraped the legs of the chips, I made a drawing of the board, and a detailed drawing of the notch on the chips, so I re-plugged the chips back in like they were originally mounted. As I went through the organ, I marked the boards I had already done with a little piece of tape...there's a lot of boards, and you will soon forget what you have already worked on.

I had the guidance of an old Conn technician to do some telephone advice. That gave me a lot of courage to tackle the job on the first organ. I did the second one on my own, and both instruments turned out flawless after the work was finished. Both of these instruments continue to play....one went to the organist for the Braves Baseball team, and the other to a general all around musician, who plays mostly pop standards.

[jbird604]

I guess the bottom line is that a 653 is indeed repairable, given enough time and patience. Great care in marking things, noting the orientation of all removable socketed items. I'd recommend taking close-up detailed snapshots of each board and the surrounding connectors before removing anything.

Given that these organs were actually quite wonderful in their design, they are beautiful to the eye, and the sound of Conn was very nice and pleasant, even considered desirable by some theater lovers, it's probably a worthy project for someone who has the time and patience.

OTOH, the VPO route is so very attractive -- the instant ability to create exactly the organ you want, to tweak, voice, swap, modify to your heart's content -- it makes you wonder if it's really more productive in the long run to simply strip out the old electronics and jump into the MIDI-fying of the console, daunting as that may be as well. At least there will be a ton of possibilities once the MIDI is installed.

But then, is there really anything you want that you can't have with the glorious native voices of the Conn? By the time the 653 came out (and it was the fourth version of Conn's massive AGO Theater organ that began in the 650), the concept had been highly refined, and the addition of the exotic Kimball solo voices and such had brought this organ to something of a pinnacle in the world of electronic theater instruments.

Of course, as good as it might have seemed back then, some of it is pretty poor by today's standards. Even cheap keyboards today have a million times better piano, harpsichord, and other such sounds than the best 1980's organs.

You just gotta make a decision and go for it!

[Jay999]

Hi John...and yes, that's what I did, after reworking those two Conns. I bought an old Allen 3 manual theatre organ, stripped it out, and installed a MIDI system, with a custom built computer, and installed the advanced Hauptwerk 3/32 in it. There was no looking back at the Conns.

There's a huge learning curve in understanding what is needed for a MIDI conversion...(choices of equipment, language, etc.) and I got really frustrated trying to figure out all of that. In the end, I turned to a custom built system, and followed recommendations from a knowledgeable friend in my ATOS club, here in Atlanta. I now have an instrument that very closely approaches the Wurlitzers that I hear on my treasured George Wright recordings.

I enjoyed the work I did on those old Conns. They taught me a lot about restoring old circuits, and when I was finished with them, I was quite proud of the accomplishments. But there simply is no comparison between the sound of an analog organ, and a digital organ. As you say, a decision has to be made....analog or digital. But once you cross over to the digital side, there's no wishing you'd gone the other way, and no desire to look back.