Hi all, I've really tried to search before asking this but couldn't quite find anyone who described the same problem. I'm new to film and chose the om2n because of some great reviews on here and other sites. I purchased one that had been sitting around for a while but was in superb condition. I changed the light seals as the foam had corroded and also removed foam from prism and cleaned the viewfinder which is still a little dim but perhaps that's more to do with the focus sceeen.... Anyway, whilst shooting I noticed that on a few occasions I would fully push the advance lever only to press the shutter button and find it locked. I'd have to push the advance lever again and could feel it move another notch or two which then fully engaged the shutter release. Is this a regular occurance for my model or is there something I can adjust do you think? Would I have nudged anything when taking the top plate off? I was very careful not to. Hope someone can help! Apart from that minor annoyance the camera is superb!