Conn 652 no notes playing on keys but all notes sounding when I press a tab down

[Max the Icie Owner]

Hi,

So today I made a trip to a guy who had a Conn 652 for sale. He said that everything worked fine when last used.

His parents bought the organ 8 years ago, and used it until 4-5 years ago. They had it tuned up and everything when it arrived. It has sat in a heated walk out basement all of its life since they bought it.

Now he has to clean out his parents' basement, and so he needs to sell the organ.

I took a look at it today, and cosmetically, it is 100%. However, not a single key on any of the manuals plays. Here is exactly what happens:

1. I turn the organ on.
2. I press a few keys - nothing happens (because no stops are selected).
3. I stop pressing the keys and select a few stops on the great, solo, and swell.
4. There is silence for several seconds, and then all of a sudden there is the sound of at least an entire keyboard if not all three keyboards being pressed and held down. I have not pressed any keys.
5. There is no way to stop the sound except to power cycle the instrument.

I have moved all of the switches back and forth to make sure it wasn't a contact issue. Originally I thought it was a problem with the keys not latching correctly or something like that, but then as I said above I discovered that the sound happens once I press even one stop tab down, and when no keys have been touched.

The pedalboard is currently detached because the organ is on a wheeled dolly so I'm not sure if that is a factor.


I'm wondering if this could be an issue with a buss bar perhaps has shorted out, or become displaced.


What are your thoughts?

Thank you,

-Max Thompson

P.S. He wants around $400 for it, but is willing to go down to $300 currently. He has given me the name of the shop where his parents bought the organ from and who tuned it up (they are still in existence). I am going to call tomorrow to get an estimate from them on repair costs.

I only have until Sunday at latest to decide on it most likely.

[tucsondave]

$300 for an organ that doesn't work at all? He'll have to pay to have it hauled away. Offer him $0.
4-5 years unused in a basement? First check for rodent damage.
Power supply faulty, cracked solder joints, circuit board connections....

td

[andyg]

Ditto to what David just said.

FWIW, here is our oft-repeated Golden Rule:

DO NOT buy an organ with fault(s) - unless:

1) You are 100% certain that it can be fixed, ie are the required spare parts available
2) You can do the work yourself, to the required standard - or
3) You have deep pockets and don't mind spending out more than the organ will ever be worth.

There are a few exceptions to 3), where the organ is of 'classic' status. Much though I love the 652, and I used to have one, it's not a 'classic'.

This is one of the Conns that went with multiplex technology IIRC. Not sure if things like keying circuits, ICs etc are available any more.

So value is just what the console alone is worth to a buyer who wants three decks and and AGO pedalboard for a virtual organ. There is a value there, but that type of buyer knows exactly how low it is.

[Max the Icie Owner]

I will see what the few shops that I have called have to say before scrapping the idea entirely.

The guy literally thought that since the organ powers on, it works. For real.

[jepsound]

[QUOTE= This is one of the Conns that went with multiplex technology IIRC. Not sure if things like keying circuits, ICs etc are available any more.[/QUOTE]

Sounds like a failure in the multiples system. Andy is correct when he says the keying circuits are very hard to find, if at all. I had a bunch of them but sold them to a gentleman in Australia. Good news is that the ICs that drive the keying circuits are very much available as they are standard TTL chips. Thea chips send various signals to the keyers and a failure of one or more of the ICs could be causing the problem. I had a similar issue with a Conn Artist instrument that used this technology. Replacing one low cost IC on the oscillator/divider board solved the problem.

Bottom line: If you do not have access to an oscilloscope, a schematic diagram of the PC board and know how to troubleshoot it, walk, rather RUN away from this instrument.

[Max the Icie Owner]

Well, I decided to pass of course. I’m not very mechanical, and really do not have much electrical skill. Not to mention that even if I got it for free, it would still cost $143 plus tax for the U-Haul trailer, and I would have to hire a few helpers on each end. Plus repairs.

If anyone actually wants it, he listed it on Craigslist, but as a 552. =-O Oh well. If anyone wants a link, let me know. Oh, and he posted in Furniture instead of Musical Instruments.


Boy.