Brother ProCal 512 Technology
Electronics
12 displayed digits using individual Nixie tubes. Negative indicated by a separate lamp.
Construction
General construction is typical of early generation machines with elaborate fabrications, brackets, fasteners and neat craftsmanlike construction.
The keyboard uses reed switches and moving magnets.
Electronics are on two double sided PCBs with an unusual interconnect plug across the width of the boards, near the centre. Therefore, no edge connectors or backplane. This arrangement is unhelpful for service as it is very difficult to gain access to much of the working circuit. Such an arrangement suggests that the designers were more focussed on a compact form and were not considering ease of service.