Dave Smith Instruments SYNTHESIZERS

hi there,
i love playing with my evolver, 
but my box has this strange behavior:
sometimes, when i turn it on, i can`t get any sound out of it.
all led`s are blinking, sequencer is running, but no sound.
(clip-led is not blinking)
help please,
as i want to integrate it into my live-set because of its
awesome sound !!!