[kalleboo]

I took apart an old bakelite phone to replace the cord with an RJ11 one (connected two old phones together with a Cisco SPA adapter, the kids love calling each other) and was surprised when there was a little bit of paper wedged between two components with the full schematic!

edit: went to the trouble of uploading some photos https://kalleboo.com/microblog/posts/111001749605994561.html