The synth shuts off randomly when moved, or will not turn on at all.
What is your Juno-Di showing (e.g., dead keys, power issues, or broken buttons)? roland juno di service manual work
If certain keys do not play, or if they instantly play at maximum volume (127 velocity) regardless of how softly you press them, dirt or dust has compromised the key contact matrix. The synth shuts off randomly when moved, or