2MB RAM Expansion

An Issue 2 Spectrum Next has 1024Kb of RAM in two 512Kb modules, which can be expanded to with a further two modules for a total internal maximum of 2Mb.

The RAM modules known to work with a Next are:

• 71V424S10Y(G) by Integrated Device Technology, Inc (IDT).
• AS7C34096A-10JCN (10JIN) by Alliance Semiconductor Corp.

(Core version 0.7 fixed a timing problem with the memory access, this list assumes you have at least this version.)

IMPORTANT: when fitting RAM note that the memory expansion sockets are slightly longer than the memory chip (40 pin sockets for 36 pin modules). This is because sockets of the precise size are no longer produced. The chip should be slotted into the left-hand side of the socket as shown here:

https://www.specnext.com/wp-content/uploads/2017/12/ram_final.jpg

Note the four connectors to the right (two on top and two on the bottom) are left empty, as the memory chip is aligned to the left. There is a small depression/hole in one corner of the memory chips. There is a cut out section on one corner of the sockets. These need to align.

NextZXOS shows the available RAM in the bottom corner of the start-up menu.