Friden 1160/1162 Board #2, Revision 2 and 3

Board #2 was used in the Friden 1160 and Friden 1162 calculators. The 1166 calculator utilized a somewhat different board #2, using more integrated circuits, but performs roughly the same functions. The 1166 board is not interchangeable with board #2 in the 1160/1162 calculators. Board #2 contains the master clock and timing chain circuitry, along with logic that generates many of the timing signals that orchestrate the operation of the calculator.

There are two known versions of this circuit board installed in 1160/1162 calculators, Revision 2 and Revision 3. It is not known if Revision 1 boards were installed in any production calculators. The components and general board layout between the two revisions but there are differences in the board trace routing as well as some slight differences in component placement. The Revision 2 board shown above is a relatively early board by virtue of the roll pins installed in holes in the circuit board at the upper left and right corners. These roll pins were not installed on 1160 and 1162 calculator circuit boards after June 12, 1969 as the result of a factory change order. The roll pins were originally installed on the boards to make removal of the circuit boards easier for service technicians. Friden eventually created a special tool used for extracting the circuit boards without requiring the roll pins, eliminating the need for them. Revision 3 of the circuit board has "1160" etched below the circuit board number, even though the circuit board can be used in both the 1160 and 1162 calculators. The Revision 2 version of the board does not carry the "1160" identification etched on the Revision 3 board.

Both versions of Board #2 contain a total of 22 integrated circuits, of which half are 7400-series TTL devices (made by Texas Instruments or Signetics), with eight 7474 Dual D-Type Flip Flops; two 7473 Dual J-K Flip Flops; and one 7400 Quad 2-Input NAND gate chip. The other 11 chips are various types of DTL ICs. The board also contains three transistors, nine diodes, 20 resistors, and nine capacitors.

The bare circuit board has Friden Part #7002183 Revision 2 or 3, and the complete board assembly has Part #7002182.