Changes
Althought the new ICs could be soldered directly to the PCB, I chose to use sockets to make any future modifcations or repairs easier. There is more than enough room inside the case to allow for the extra height needed for the sockets. The components can be added in any particular order, although to make testing and debugging easier, I added only the 64K RAM components first and tested this before I continued with the floppy control components. The minimum parts required to get the extra 64K working are: R28, R55, C12, C13, IC12 and IC13. Remember that the black bridge wires must also be connected in order for the CPC to run in this state.
If you intend adding an ABBA switch to the CPC, it's a good idea to make the modifications to the external floppy connector before you solder it to the PCB. If you have borrowed the floppy power connector and leads from a PC, then you will need to remove the yellow wire from the connector and move the red wire to the position where the yellow wire was, as Amstrad (in their infinite wisedomwisdom) decided once again to steer clear of unnecessary things such as standards.
When all the components have been added the board will look quite a bit fuller and you should now have a 6128+ PCB in front of you.