Changes

Note that the photos seem to be showing a spanish remake, not the origial hardware (as indicated by the "P DE FRANCISCO" text on the solder side). The two schematics are a "remake-of-the-remake" (ie. the PCBs seem be authentic old hardware, the latest YYWW year/week datestamp on the chips is from 1989. The schematics were drawn at a later time, when reverse engieering engineering how the those PCBs worked).