Turning home organ rhythm units into standalone drum machines

[publicradio]

I recently bought two rhythm units from ebay: A Hammond Rhythm II, and a Hammond Aurora 8200 series rhythm unit. The Aurora one is exactly the same as an Auto-Vari 64, just not a standalone version.

Now with the Aurora/AV64, I have the connector in the back that looks like one of these, and then just wires sticking out of that. There are 14 wires sticking out of the connector. I assume two of these are for power and two are for mono out, and the remaining 10 probably control the rhythmic accompaniment of the organ.

Can I just get a wall wart, hook a phone jack up to my audio out, and use this as an Auto-Vari 64? That is my hope, and why I bought it. I would like to do the same with my Hammond Rhythm II, but I am not seeing any demos or tutorials of this on Youtube. How do I do it?

[BertKoor]

Well, you have to solve the puzzle of what is what on that connector. Or find schematics. Some electronics knowledge may help.

You are at risk of frying the thing in the process of solving the puzzle. Apply the wrong voltage or by accident shorting some connectors will let it die.

[Ah_Dziz]

You should be able to figure out which wires are the power very easily with a multimeter. Once you've eliminated the power (to avoid zapping anything) you should be able to find the audio by trial and error with either a scope or a test cable. The rest are probably just control voltage for the various ways the thing interacts with the organ. Those can be replaced with buttons or switches if you want all that functionality without using the organ.

I know this is an old thread but I'm in the process of adding individual outs to the top and bottom manual and the drum machine as well as an input for the Leslie so I figured I'd mention how I sorted it out. I didn't bother adding "non organ controls" to mine but it would be simple.