Texas Instruments SR-60A

This Texas Instruments SR-60A programmable desktop calculator was introduced early in 1977 and succeeds the SR-60. At first glance the SR-60A seems to be an SR-60 with a factory installed memory expansion, the base model could hold 1920 program steps and 100 memory registers. A second memory expansion was available as an option. The huge printed circuit board (PCB) with a total of 27 TMC0599 RAM chips was mounted below the keyboard next to the Main PCB. A fully-optioned SR-60 could hold programs with a maximum of 5760 steps and 430 memory registers.