Hi K.
With a little research, this is what I found about the All New Remington Portable. By the looks of it, I'd say that a manual for a Remington Quiet-Riter would be a pretty good place to start. Hope this points you in the right direction,
Sky
We humans go through many computers in our lives, but in their lives, typewriters go through many of us.
In that way, they’re like violins, like ancestral swords. So I use mine with honor and treat them with respect.
I try to leave them in better condition than I met them. I am not their first user, nor will I be their last.
Frederic S. Durbin. (Typewriter mania and the modern writer)
