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I've been unsuccessfully trying to get hold of a Native Instruments B4D drawbar MIDI controller. So I decided to build my own. I had a Raspberry Pi lying around, and hadn't come across this site back then, so I decided to use the Pi to control it all. I've tried out IO piggy back boards and ADC piggy back boards. The Raspberry Pi experiments were successful. I have a Java program reading the IO ports and the ADC channels, and sending MIDI events over the Pi's USB to a USB-MIDI adapter and a synth. Then I obtained some Hammond drawbars. They aren't B3/C3. They are from an H100, allegedly. I've read the posts here, about the original wiring of the drawbars, but I'm still confused. I understand that they are giant switch buses and not potentiometers. But all the buses are connected to each other by a little circuit board at one end. I wondered if there were some differences in resistance between the ciruit board connections, but it doesn't seem so. It's not a show stopper as I can unsolder the circuit board and add some resistors as mentioned elsewhere on the forum, but I'd love to understand what I'm disconnecting. Can anyone kindly explain how everything isn't actually connected to everything, please??