"To keep the prices down Sinclair used faulty 64K chips (internally 2 X 32K). All the chips in the 32K bank of RAM had to have the same half of the 64K chips working. A link was fitted on the pcb in order to choose the first half or the second half. It was possible with a few logic chips for an experimenter to have access to the faulty 32K bank with all sorts of odd results possible!" ‎· российский соотечественник