I've recently purchased a Richoh af 70 and I've only used one roll to test the condition of this thrifted camera. I have very straight scratches that can be felt on the negative that show up white once scanned. I own a few film cameras and get them processed at the same vicinity so I'm positive it is the new camera and its also not the pressure plates since I ran an old negative through the film roller with the door open. I haven't liked a camera this much in a while and I'm hoping this can fixed and interested in how I can do this myself if possible
Don't rule out the pressure plate prematurely. Otherwise, while you're looking at everything else, you might find that the pressure plate is at fault. In particular, running film through the rollers with the door open should increase the likelihood that the pressure plate is involved, unless the camera has a completely different design from what I found while searching for the camera model you mention. The solution is the same regardless.
- Identify the side that the scratches appear on, front or back.
- Use an air compressor to blow foreign particles out of the camera.
- Run a fingernail along all parts of the camera that have contact with the film.
- Check everything, but especially focus on the areas that correspond to the side of the film on which the scratches occur.
- If you have poor sensation in your hands, find someone else to do it for you.
- If you don't find a source of the scratches, it might have been a loose piece of grit that got blown out. Shoot another roll of film to check.
- If you do find a camera defect that could cause the scratches, get a set of knife sharpening plates. Use the finer plates to sand away the cause of the scratches. In my case, I have 200, 500, and 800 grit plates. Unless the defect is very large, I would start with the 500 plate, then finish with the 800 plate. (Higher number is finer.) Try to sand perpendicular to the direction the film will travel and away from other surfaces that will contact the film.
- Use the air compressor to blow the camera out again. Then use a damp paper towel to wipe everything down.
- Shoot another roll of film to see if you've fixed the problem.