Bugfixes (Mainboard marked Rev 2.007)
Issue 1: Accents not triggering drum voices in voices test mode
IC3 (CD4049) is not suitable for the job of interfacing the Atmega microcontroller with IC111 and IC114 (CD4051 Multiplexer). A small circuit needs to replace the entire chip in order to interface the address lines correctly.
A single MOSFET per inverting buffer channel with drain resistor replaces IC103 and provides IC111 and 114 with enough drive strength to change channels
better description and circuit schematics soon