These large models retained cast iron top rings/grates/trivets/pan rings (The first two are Primus terms, the later two are terms used you'll also come across on this forum) until the end of production, by which time they were somewhat archaic. Primus were always based in Sweden. The lettering on these large cast top rings changed to simply 'Sweden' after Optimus bought Primus in the early 1960's, so they could be used for both brands. Fantastic stove, these large models are impressive!
Yes, I have learned a lot about these. Yes mine has had a few repairs. It is definitely a Primus. It does not say Optimus anywhere on the stove. But the stamp on the bottom, definitely seems to make it newer than older.
I believe I sent a picture. Imprinted on the bottom says AV5z. I was told that this makes it newer than originally thought.
