Additional Pictures 


This Radio Shack EC-425 was manufactured in October 1974 by
Texas Instruments  (Date code 454 wk 45 yr 1975.

The printed circuit board (PCB) of the Radio Shack EC-425
is identical with the PCB of the SR-10.

Close-up view of the TMS0120 calculator circuit and the four display drivers.

horizontal rule

If you have additions to the above article please email:

Joerg Woerner, May 11, 2011. No reprints without written permission.