I've got an MX in great shape except that the viewfinder has a small dark streak from the centre to the bottom - it looks like a stain. I've determined that it's not on the mirror or focussing screen, so I think it must be a problem with the prism.
So anyway, I have a couple broken Pentax MEs around and I'm wondering if A) the prisms are interchangeable between these models and B) whether it seems like a reasonably possible thing to do. Thanks for any and all help. Damon