Additional Pictures 


The battery compartment of the SR-51 gives access to the electrical
contacts used to connect the PC-100 printer cradle.

Different font sizes found on an early SR-51 (TOP, Serial No. 0001589)
and a later SR-51 (BOTTOM, Serial N
o. 0044521).


The Main printed circuit board (PCB) of a SR-51 calculator. The brain of the
calculator uses the TMC0501 and a stack of 2 SCOM (TMC0522,523) circuits.

A second PCB holds the keyboard contacts, display and driver circuits. 

The printed circuit board PCB of an early SR-51 reveals production codes 
of week 42 year 1974 on the SCOM chip holding the firmware.

horizontal rule

If you have additions to the above article please email:

Joerg Woerner, July 14, 2002. No reprints without written permission.