Just in case this picture has begun to baffle you, we are now looking at the insides from the right-hand side, not the front!

This shows the arrangement of the two ROM boards and the Econet module.

I can't pretend to understand how these little ROM boards work. One of them uses up ROM slots 0-3, which is why the ROM cartridges on this machine are not filled, and the other rather ingeniously allows certain ROMs in the standard system ROM to be replaced by ROMs on board.

How all this works is something of a mystery to me, but the little yellow spring clip and the various jumper settings on the boards make it all work. If I remember rightly, the board containing Wordwise and the Master ROM has a set of pins which lay directly onto the CPU, but I can't quite recall and I didn't take the board out for fear of not being able to put it back correctly.

The other board requires the main system ROM to be removed from its usual home and inserted into the board - notice here that the ROM is a version 3.50 ROM, not the standard MOS 3.20. More on that later!