Spectravideo 738 X'Press to MSX-2 upgrade

There are two mainboard models. The earielr (3.2, most popular in Poland) has no space for additional hardware, the other has spare places for extra chips.

128kB VRAM

In version 2.3, desolder both 4416 (IC22, IC25), solder precise sockets and plug the SVI128V board with 128kB DRAM on it. (For test purposes, you can just replace 4416 with 4464.) The /CAS of the second 4464 pair should be connected to pin 60 of VDP (IC37).

In newer board replace 4416 memory with 4464 and add next two 4464 in spare space.

Z80 CPU @ 6MHz

To be continued...

MSX2+ ROM

To be continued...

Files for download

svi128v.zip 15.5kB (2005-04-13 20:42)

Board for 128kB VRAM upgrade - 4×4464 memories. Board picture and Eagle data files.