The previous project logs were all written in retrospect. With this one, I'll be caught up to the present.

Board bring up was fairly uneventful, just a ton of soldering. It all came up on the first try, and I did not need to add any buffering. My Arduino Uno clocked all 14 shift registers at once, no problem. The only big issue was not my fault. The 45 year-old original board I'm interfacing with had one broken tab:

I didn't really fix it properly, just soldered some hookup wire and wadded it up to jam into the connector. I don't expect to be unplugging it very often.

Partially, progress has been a little slow, because it's just too fun to play, even with partial functionality! I'll post a video after I get the volume pedal working.

I also have a DPDT switch near the lower manual that was originally part of the accompaniment functionality. I'm not sure exactly what it did because it didn't work when I got it. I'm thinking of making that switch some sort of preset button, or emulate a third keyboard, or shift the upper manual up and down an octave. Let me know if you have any other ideas in the comments.