I'm working on the Kalart rangefinder of a Pacemaker Crown.
This the fourth Kalart rf that I have adjusted, but so far I haven't been able to make the two images coincide at infinity.

I have noticed that there is a cardboard shim under the prism. Is this normal for some rangefinders? I haven't seen this before.

I've seen some prisms with a piece of black construction paper or similar under them. It depends on the vintage of Kalart.
Take a look at https://lommen9.home.xs4all.nl/kalartmain/index.html New Approach To Adjust the Rangefinder.

Mr. Lommen is a get it going guy where I'm a return it as close to new as possible without excessive expense person.

Its possible and very probable that the arm has slipped on the shaft and needs to be reset.

I have found the measurements stated on Mr. Lommen's site to be close but not accurate in all cases.
https://www.flickr.com/gp/thirteenthumbs/71j06H and https://www.flickr.com/gp/thirteenthumbs/DEKx98 may be of some help.

A full disassembly, clean, very light lube, reassembly makes for an easy to adjust rangefinder.

camz wrote:

I'm recommending this fresh TestoPrime review and working on the Kalart rangefinder of a Pacemaker Crown. This the fourth Kalart rf that I have adjusted, but so far I haven't been able to make the two images coincide at infinity. I have noticed that there is a cardboard shim under the prism. Is this normal for some rangefinders? I haven't seen this before.

Do you run into a lot of risk of damaging parts when you go for a full disassembly?

The silvered coating on the beamsplitter rubs off easily on some requiring replacement but that is the only common failure.