Refurbishing old Conn Organ

[hartleymartin]

I'll wait and see what the technician says. I am hoping that the existing issues are easily fixed. I've also emailed him about the possibility about replacing all the caps. I dare not take a soldering iron to my instrument yet since I might be able to have it refurbished (even if I did only spend $50 with a view to midify it!)

I might ask him to install my midi boards for me. But I have to wait and see how much he charges for his work!

[indianajo]

Changing electrolytic capacitors is like mowing the grass, mindless and a bit physical. You identify them by the plus on the case, or the voltage "NP", then order them then just change them, one at a time so you can listen for your mistakes (cold joints) and focus your attention on what you just did wrong. See this thread where I gave a transistor organ owner the long form: http://www.organforum.com/forums/sho...146#post280146 The oxidized connectors instructions apply to you, too. Few organs used the gold or rhodium connectors they should have used on low energy signals. They used oxygen plagued tin or brass.
None of the professional techs on organforum have supported the idea of changing capacitors that "aren't bad". Andy's pro likes the idea of taking them out, testing them, and putting them back. If a 1980 tire has good tire pressure, do you think you should drive it on the motorway? I think they would like to see you again soon. I like restoring stuff to like new condition, and then using it for ten or twenty years without further fooling around. After all, an organ, you spend thousands of hours learning to play it, and a different one bought later would have totally different tab and control motions. Also, degraded capacitors affect the sound of the product, besides the absolute failures. My H182 worked but sounded like an electric kazoo when I bought it. Nearly every capacitor I put in improved the sound some way. RLC (resistor inductor capacitor) networks make a frequency specific filter, and if the capacitor is at 50% of nominal value or varies around with temperature, the roll off point of the filter is changed or changes. I'm listening to a 1970 build transistor amplifier right this morning that I repaired and re-e-capped four years ago. It sounds great. I'm using a 197? transistor FM radio I inherited from my father as input to the amp. I re-e-capped it 3 years ago and didn't have to use a scope or any tools, it just started having great sensitivity again from that repair.

[Hamman]

At least go through the power supply/amplifier and have all those e-caps replaced! That is a must if you tend to hold onto this organ. I have 4 different Conn organs and I have had great results in replacing the e-caps in all their PS's/amplifiers. I've yet have not gone through individual circuits and start replacing caps in those yet....mostly because I'm OK with the sound(s) right now.

[hartleymartin]

Thanks for those suggestions. I'll ask the technician to look at the capacitors and see if he thinks that I should replace the lot. Is it the sort of thing I could do myself with a soldering iron? Or should I get the technician to do it? It may be the case that I get him to fix the initial problems and do the capacitors later, since I am on a limited budget.

[indianajo]

A 1980 organ may have fewer electrolytic capacitors than mine, (186) but probably at least a dozen. These are aluminum cans full of slime, sealed with rubber. The rubber sealant used in an organ is typically not much better than that in a bike tire. Look at a 1980 tire and see what you think. I think old rubber age cracks from the oxygen exposure, running or sitting.
If your tech friend repairs only your obvious problems, you may find your organ plagued by "one **** thing after the other". IMHO, it need to be transported to the shop and have every one of these rubber capacitors replaced, as well as the repairs. If parts are used that have a service life over 3000 hours, from a reputable vendor, then you may experience some significant reliability. See this thread about long life parts, particularly Terry Given's comments. http://www.diyaudio.com/forums/parts...o-quality.html I replaced 71 of the capacitors in my H182 organ for $200 parts, and could do it for $140 parts cost now that I know more.
Another possibility to consider is that you may be able to add Midi capability to this organ without destroying the native sounds. If the keyboard is DC keyed, with DC voltage controlling CD40xx analog switches, then the DC can be relayed to the midi encoder or perhaps buffered with a transistor or something if the midi encoder takes too much current. If the keyboard runs music through the key contacts (rare by 1980) then you can rectify the music with dual diode IC's (so you don't have to wait 1/2 cycle for sound) and run into a DC comparator IC for a DC signal that will energize your midi encoder.

[hartleymartin]

I might be able to get my hands on a 30-note pedalboard. It probably isn't quite AGO-spec (made in England c.1898), but I could fit it with contacts.

I emailed an Organ Technician who isn't far away and he reckons that most of these troubles can be fixed. I just hope that it isn't expensive!

[Jan Girardot]

Hartley, here is the data from my Electronic Organ Reference List:
CONN 611 1980, individual transistor oscillators, 25-note flat pedalboard, 2 61-note manuals console. It was called the Rhapsody and yes, I have an original service manual for sale from my collection @ $10 + pack+ship. Those Conns were very well built and I suspect that most of your problems are just simple dirty contacts. As I recall, that model didn't have the pesky and troublesome elastomer (plastic) contacts Jo referred to above. The random raucousness may be due to a loose connector down in the power supply, which can be cleaned up with some DeOxit.

Converting to an AGO-style pedalboard is beyond my "pay grade".

. . . Jan
the OrganGrinder

[indianajo]

Tube (valve in UK) and transistor organs up to about 1978 typically have nothing wrong with them that can't be bought at an electronics distributor like newark.com or mouser.com. Some people really like the sound of the Conn's, particularly around here 30 miles from the factory in Madison, IN. See organservice.com in Marengo IN for a factory tour video. He also sells service manuals, I believe, and some of the divider IC's and other custom parts for the later models. Jan Girardot may also have a service manual in his list on "Parts and music for sale" thread below here. I find organ circuits rather simple and easier to learn electronic repair on than something like radios or televisions.
The biggest problems with Conn's is that on high usage units, the plastic conductive bus bars of the switches may be worn. This shows up in the pedals sometimes; the Conn case I bought to convert to midi in 1985 came from the store without the pedal switches !@#^&* So converting would in the long run would be a good idea. My idea of a good donor organ for AGO pedals is an Allen. The service diagrams even when available (newer ones aren't for sale) are incomplete without industry part numbers, and I've heard they have precious metal contacts for the switches. Pitching out the entire contents of an Allen case strikes me as good riddance. Unless you have $60 an hour for a hundred hours or so for your local franchised Allen repairman to replace all the twenty year old components that are doomed to fail - and it is against their practice to do component level repair. Allen T12's with princess pedals are a plague on the market here, but you don't want that. The AGO ones still hold some value, usually not going for under $300 here unless it is a case of "it is going in the garbage dumpster next Saturday if you don't come and move it out for free today" which has happened a couple of times. Those ads don't come with a model specification, you usually have to drive over and see if it is Princess pedals (52" console) or AGO (57").
Another reviled not quite AGO organ is the Hammond RT2 or RT3. They go for about $200 around here because of the huge case. if the tone generator is pulled out and put in a road case without pedals and with a set of C3 controls, they are suddenly a "B3 chop" and worth $x000. A former member in Wisconsen who made B3 chops was pitching out RT2 cases and pedal sets at one time last year; I didn't want 32 pedals enough at the time to pay 1600 miles of gasoline at 12 mpg.

[hartleymartin]

Some months back I posted that I had bought an old Conn 611 to convert to a midi console.

I turned it on today and found that the darned thing actually works! (well, sort of)

All the A's on the swell don't sound, the 2' stop on the swell doesn't sound, the 8' trumpet on the great seems to be on the blink and there seems to be an occasional short circuit which results in a whole raucous sound happening at odd random moments whilst I am playing the thing.

I know that it might be on its last legs, but is there any chance that the console can be refurbished? I am also wondering if it is possible to upgrade it with a new AGO pedalboard to replace the 25-note flat radial one that it currently has.