The MIDI function they forgot, for YAMAHA TX816 only !This is a very simple MIDI Switch based on a common 80C31... I have done it to control through MIDI the "Output Slot" button on the front panel of the TX816... It provide a full remote control for TX816... It is really cool to access each TF1 modules, while editing or dumping, whitout having to push any button. The Midi channel of the switch is set with 4 dip switches. The Midi controller used to perform an"Output slot change" is actually the number 20. The MIDI Switch pcb is piggy back mounted on the TX816 selector pcb. Psu and MIDI are extracted from this pcb, simply, the TTL counter (an 74LS293) has been removed and emulated by the MIDI switch...
- schematics & pcb
- eprom software source code
- eprom software binary file ( to be burned in the 2764...)
Actualy i think this mod should be done
using only a little PIC chip, and less parts on a smaller pcb !