- Make sure the Drumulator is in Segment Mode (SEGMENT light is lit).
- Hold down ERASE and tap CASSETTE. The display will flash 'PooF'.
- While continuing to hold ERASE, press ENTER. The display will continue to flash 'PooF' until you release the buttons.
- To abort the process, release any buttons before pressing ENTER.
Source: Drumulator — emu-drumulator-owners-manual (manual)