Nikon F2 DP-1 finder problem: speed cannot change

[Renamable]

Just got a bargain sold as is from yahoo. Everything works fine without the finder, but the dp-1 cannot work properly. I can neither lift the ASA ring to set film speed or rotate it to change shutter speed,. I can change shutter speed with the dial on the body so I can just purchase a 3d printed waist level finder but I still want to repair the original finder if possible. Anyone has sandy suggestion or encountered the same problem? Thanks!

 

[Kino]

There could be any number of reasons why it does not function properly; too many to guess.

Maybe someone just took a DP-1 with a destroyed metering system and glued it down to have use of a reflex viewer, when the non-metered prism was not available to them.

Here is the service manual. It may point you in the right direction if you are mechanically inclined...

https://learncamerarepair.com/downloads/pdf/nikon-F2-DP1-service.pdf