You will need to do a CLA on the shutter. The timer is a clockwork mechanism that is regulated by a pawl. By turning the gear by hand the shutter will release. This is a common problem with all shutters that have timers. I use watch oil on all of the pivots of the clockwork. Take your smallest jewelers screwdriver (flat blade) and pickup a small drop. Get some Superlube and a artist brush for sliding contact, remember a small amount is needed. No oil or grease is needed for the shutter or iris. I wil not flush out a shutter if it is fairly clean. Just take apart clean parts with lighter fluild and reassembe with correct lubrication. Hope this helps, Steven.