The Olympus OM-1 was released in 1972 as a revolutionary 35mm SLR, offering a professional-grade, fully mechanical system in a body significantly smaller and lighter than the competition. It featured a bright viewfinder and unique controls, such as the shutter speed dial located around the lens mount rather than on the top plate.
Are your pictures coming out clean? Looking into the mirror box via the Lens mount does not mirror intact and go up and down cleanly when in bulb mode when you release the shutter. Looking though the eyepiece a an evenly lit wall is there any shadows?