Yamaha MU100R Owner's Manual page 177

Initialize Functions (INIT)
Factory Settings (FactSet)
This restores the original factory settings of the MU100R.
NOTE
This function replaces internal performance data to the "Internal Performance 2." To restore
the "Internal Performance 1" (loaded at first), load the data from included floppy disk. (Refer
to the "Sound List & MIDI Data" booklet.)
Selected Sound Module Mode:
Extended General MIDI (XGInit)
General MIDI (GM Init)
Computer Music (C/MInit)
166
Utility Mode