Welcome to the forum.
This article gives a general description of the Herters presses. Googling brings up a bunch of other articles and forum threads.
You may want to buy the adapter for accepting standard shell holders.
Ch4D used to sell them. Check there.
The mechanics of the ram sticking is curious. I believe those pressed have a detent ball of some kind for keeping the arm up? If that was gone or messed up in some way, I suppose it might jam it? Other than that, I'd have to look at the thing to figure it out.
Try PM'ing board member F. Guffey. I believe he has a number of older presses and may be familiar with your's?