My new/ sh om4 jammed during the first reel after 22 frames. The wind on won't move, the shutter rlease won't fire ( batteries are fine ) in either electronic or mechanical mode. The rewind button has stayed down and the takeup spool is free. No sound of loose screws. Any ideas?
The shutter will lock when the batteries die, but it resets automatically when you put in new ones. So there is no "reset" you have to push like on the OM-2. If you changed the batteries with some known good ones without any luck, it sounds like it may be time to sent it for a repair.
If it has never been serviced, OM-4s are of an age where they need a good overhaul anyway. It should give you many happy years after that.