Quote Originally Posted by Ryuji View Post
In Mamiya TLR’s, shims are also used to align viewfinder screens... as a general suggestion, do not disassemble the viewfinder chamber, even if it is dirty. There is little to gain and a lot of risk to misalign the screen.
As other posters have encouraged people to do and as detailed here, I have already replaced the foam under my focus screen. It was deteriorated, but interestingly not enough to lose enough springy-ness and be the cause of the problem.