This is mine, bought about 30 years ago, I do not remember how much (but a lot cheaper than a Rollei), nor where (but must have been at a local dealer here in Paris, because it was before internet).
It is called "Planet CF 66A-F" (no known brand ?), has a fair lens from Will (Wetzlar) and (by the base plate) was made in Italy for Cine+Foto GmbH.
It is heavy, simple and sturdy, and worked well all these years ; I just had to readjust once the slide changing mecanism, but it is very easy to service "oneself"
It has only manual focusing and slide changing (both working with the same cable remote control) and the lamp has a two-step brightness control (dim and full). The fan is ON all the time the projector is powered.
It uses Rollei slide magazines, indeed ! and I have all my (6x6 and 645) slides under anti-newton glass, of course.
By the picture, does it look like a branded model that you know ?