pdb@sei.cmu.edu (Patrick Barron) (06/09/88)
I opened up my 7300 a few days ago to look around inside, and now I have a few questions: 1) I may not have looked hard enough, but I didn't see any slots or empty sockets, or anything resembling anyplace to plug board-level expansion in. Where do such boards go, and how do they talk to the main board? 2) In this newsgroup last week, I saw some instructions on how to expand the memory on a 7300 to 2mb on the main board, and thought that this would be a good thing to do. Of course, when I opened the machine up, I saw all the 64K DRAMs soldered in. Now, I'm not at all un-handy with a soldering iron, but desoldering 72 chips, putting 72 new chips in their places, and expecting the whole thing to work later, is not my idea of fun. It would probably be much easier to build my own expansion memory board. So, can anyone tell me (or point me to a reference) what the interface specs are for 7300 expansion boards? 3) The diagnostics floppy can tell the difference between on-board RAM and expansion RAM - I assume it can do this because expansion RAM is in a different place in physical address space. Where does expansion RAM live in physical address space, and how much expansion RAM can you have? --Pat.