The 'I can power the whole board with a Trinket' notion quickly faded when I realized that components on the card reader board were using enough of the power to silence some of the buzzer notes. The first idea I had was to cut the traces from the buzzer, but i discovered that the card reader board was 4 layers. In frustration, I sawed half of the board off. This, combined with I carrying Bruce Hall's method of note entry over into a slightly modified version of Dr. Leah Buechley's beep method, resulted in consistent output to the buzzer.

I then began fitting the new circuitry into the old enclosure.