> > >> I misremembered the 350 (I don't have one): it can have memory in the > I/O > >> card cage, but it also has memory daughter cards, two of them, with 40 > pin > >> connectors. > >> > > Many years ago I upgraded those daughter cards and changed them from > using > > 64kbit chips to 256 kbit chips. I don't remember the exact type which I > > used. It was very successful. The system went from 512kbyte total to 1280 > > kbyte total. There were no stability issues what I remember so the > refresh > > seemed to have worked fine. > > You're talking about the Pro-380 daughtercard, right? It has a jumper on > the card to indicate to the software whether the card has 64k or 256k > chips. I don't see anything like that in the Pro-350 description. > > > No. Actually the 350. I still have the machine, though it hasn't been ran for ages. I did this "upgrade" more than 25 years ago so the (my...) memory is a bit fuzzy. But I think I remember that it was just a simple change of chips. No extra wiring needed to handle the extra address bit, it was all there.
I just looked up the tech manual page 5-46: "The system can address up to 512kbytes per daughter board slot" so my memory wasn't that bad after all.