I've got a couple of Olympus SLRs I got for cheap on eBay I need some assistance with.  
 
First on is an OM2n with a funky shutter.  When I first got it, it worked fine in spite of being sold as is and unreliable.  Shortly after that, the ope

 There is indeed a screw that holds the drum onto the spindle, right in the middle... if the screw's come out, ithink there might be some other parts floating around in there too.  I haven't gone into the OM2 to this depth, but from other models

 Rick:
 
About what I expected.  Too much to hope that there is an access port just to reach the shutter.  If I read the diagrams right, the only thing that came loose is the screw, it goes through the drum and into the winding shaft -- OM2 shutt