On page 28 of the TX81Z Service Manual it explains the test/reset
procedure. Press the <- Master Volume key and the Cursor key while
powering up the TX81Z. This will start the test mode at Test #1 and
load all the presets into memory. It also resets the midi channel to
Channel 1 and the Effects will be the factory default along with some
other settings. The full range of tests can be run if desired.