STC:
h to reset the RM1x’s settings to the factory condition, you can perform the Initialization operation.
1 While holding down the [OCT DOWN] and [OCT UP]
buttons and the F#/Gb key [ALL] located at their right,
turn on the STANDBY/ON switch.
2 When “RM1x” appears in the display, release the keys.
3 When initialization has been performed, “Factory Set”
appears briefly in the display.
CAUTION!
When initialization is performed, all internal memory will be
erased. If you wish to keep any of your data, you must save it
to floppy disk before initializing.
http://www2.yamaha.co.jp/manual/pdf/emi/english/synth/RM1xE1.pdf