Z80 Mark III (continued)

This is the Z80 Mark III Random Access Memory (RAM) board. It contains four 2K byte chips for a total of 8K bytes.

The two switches at the top right choose where in the address space the RAM is accessed. Choices are 0000-1FFF, 4000-5FFF, 8000-9FFF or C000 to DFFF. For the Mark III, the switches were set to put this 8K bytes of RAM at address 0000-1FFF.

All the other chips are buffer and support chips. The empty socket on the right side of the board was for future expansion when more memory was to be added.