Meissner model 9-1065

Hello. I have a Meissner model 9-1065 that needs some servicing. Now, being an uncommon piece that's 70 years old at the youngest, this thing is impossible to find literally any helpful information on past "here's how to turn it on, and here's how to record something." Now, since I need a repair document, but I don't want to spend money on said documents (call me cheep, I don't care), I don't know how to find them. If anyone can help, I'd be thankful.