Friden 1160 Circuit Board #4

Board #4 in the Friden 1160 calculators contains mainly sequencing and control logic, and is unique to the the calculator. Board #4 and Board #5 combine to form most of the logic that orchestrates the operation of the calculator.

Board #4 contains 23 integrated circuits. Two of the IC's are TTL 7474 Dual D-Type Flip Flops, and the remaining 21 ICs are DTL devices. Along with the ICs, there are 40 diodes, 13 resistors and five capacitors.

The bare circuit board has Part # 7002187 Revision 2. The completed assembly has Part # 7002186. Note from the photo that this board has the roll pins in each top corner of the board, indicating that it was manufactured before June 12, 1969, when a production line order was implemented that removed the installation of the roll pins in the circuit boards.