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Friden 1150 Logic Schematic
This is a logic-level schematic for the Friden 1150 printing electronic calculator. The 1150 was Friden's first printing electronic calculator, introduced in February of 1968 at a retail price of $1,495. The 1150 was the first of a series of 115x calculators, which also included the 1151, 1152, 1154, and later, the 1155 and 1155A calculators, which were much more advanced programmable scientific calculators, but shared many mechanical components, including a similar printing mechanism and cabinetry. The 1150, 1151, 1152 and 1154 calculators shared a common architecture based on the original Friden EC-130, utilizing small-scale DTL and TTL logic, and three counter circuits in conjunction with a magnetostrictive delay line. The later 1155 and 1155A machines utilized large scale MOS integrated circuitry, with a microcoded architecture, Binary Coded Decimal math unit, MOS ROM for microcode storage, and MOS RAM for register and program storage.
The schematic includes all of the logic for the 1150 calculator at the gate and flip-flop level. The schematic only includes the circuitry located on the five plug-in circuit boards, and does not include the power supply, printer driver, delay line amplifiers, and motor start/stop circuitry.
The numbers preceded by an "M" inside the logic symbols indicates the board number and IC package on the board in which the logic element exists. The first digit after the "M" indicates the board number, and the next two digits indicate the package number on the board. In general, the package number is identified by etched notations on the circuit board near each package.
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