MD: Digital Sound Preset on MZ-R900

This is the point: I set the treble and bass settings of the Digital Sound Presets "Sound1" and "Sound2" on their zero levels (Bass +-0, Treble +-0). Then I switched between no sound settings (nothing appears on display) and "Sound1/2" (sound1/2 appears on display :). Even the levels were

MD: problem with erasing the name bank without any disc

Hello! Recently I bought R900, my first experience with MD. And this is my (first :) problem: I can't get into "edit" menu and erase the name bank when no disk is present. I press L (MiniDisc turns on), find "edit" menu and press L again. Then message "BUSY" blinks for a while and then message