Shutter problem of 3.5E3

Dear all, my 3.5E2 has a problem:
The shutter opens and does not open in the next time. It opens normally the next next time.
i.e. it opens alternately. Is it a series problem for repairing?
Thanks.
The shutter opens and does not open in the next time. It opens normally the next next time.

i.e. it opens alternately. Is it a series problem for repairing?
Thanks.