This document is an internal Friden "Master Design Document" (MDD) that
describes the entire design of the four-counter version of the EC-132
calculator (Serial Number below 3902). It documents the signals
used, logic gate connectivity, and component connectivity and location
on the circuit boards for the Four Counter EC-132 (Serial Number <3902).
This document has not been decoded fully in terms of how to read/interpret the
content. It is presented here in hopes that it will solicit discussion
and perhaps lead to the document being decoded. If you have comments or
questions about this document, please contact the curator of the museum.
Section I (glossary) appears to define all of the signal names
used in the machine. Section II (logic schematic), appears to
define the machine in terms of its logic elements (gates, inverters, flip
flops), and how the logic elements are interconnected. Section III
(construction file) appears to define the actual component netlist
and cicuit board component layout.
The document also includes schematics for various subsections of
the calculator, as well circuit board layouts, with all components
identified by a number that refers back to the Card Map Legend page to
specify the component value or part number.
This document is intended to be used with the
Friden 132 Logic Schematic
for troubleshooting purposes. The Logic Schematic can be used to identify
the general logic that could be causing a problem, and the MDD then used
to track down the actual components used to implement the logic in question.
From there, diagnostic testing can identify any failed or out-of-spec
components fo replacement.
Any re-distribution of this document, printed or electronic,
must include the watermark indicating its source as the Old Calculator Museum. Thank you.
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