Thursday, March 27, 2014

Digital Analog

Progress update: The Rodger 32C console has all keys midified. Now I only need to midify the expression and crescendo pedals, presets, stops, and possibly a sforzando button, along with finding a dedicated computer, amp, and speaker system. Some contacts need cleaning, and some minor ribbon cable shortening is in order, but I ran out of IDC-16 cable end connectors so the photo-op will have to wait for now.

 As some of you may recall, I used the MidiBoutique HWCE2x Bundle #3 along with 5 Keymux 64's and 20 BO-16 breakout boards to eliminate the need for using diodes or solder. Probably next time I'll save money and do my own scanmatrix, but putting together an organ like this for the first time was daunting enough without that challenge.

 Of course, there were a couple of wait-a-minute moments. I had changed out all the reed switches in the pedalboard. One word: Don't! (if you don't have to). But I did. And of course, there were a couple of pedals that insisted on continuing to sound after depressed. Moving the reed switch further from the pedal magnets ever so slightly took care of that easily.

Then there was the section of missing notes on the swell keyboard. All the notes played until about 16 notes up from the left, then stopped for 16 notes, then resumed. Light bulb moment. 16 is a special number with computers, and also happens to be the number of wires in the ribbon cables. Solution: It always helps if you plug ALL of the cables in.

Lastly, a little peculiarity of the Keymux64 system (which allows me to keep the busbar under the keyboards intact and just attach one wire per note to the BO-16 breakout boards). Turns out these Keymux64 boards have two power supply terminal connector screws each, and each of them needs to be connected to a corresponding terminal on the HWCE2x motherboard. I have no idea why, but perhaps there are two different voltages or one is used for switching, or perhaps it is just extra current capacity.  But the two screw terminals do not appear to be electrically connected at least when the system is unplugged.  Solution: Two parallel wiring systems.

Next step? Replacing the swell expression pedal potentiometers. My 32C had the retro-fit modification that uses a light bulb and photoresistor system to smooth out the inevitable glitches that develop in an often used pot, but I'm not sure I will be using that here. Might put it on the 32B instead.

Until next time, enjoy organ music!

PS - here's a quick snapshot of the mounted PC boards before adding ribbon cables and modifying the power supply wiring slightly.


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