Description
Technical Manual (TM 9-1220-221-20P) for M18 Gun Direction Computer January 1969
This Technical Manual TM 9-1220-221-20P covers the M18 Gun Direction Computer with equipment and is dated January 1969. The complete equipment is identified by FSN 1220-448-0131.
The publication is an official Organizational Maintenance Repair Parts and Special Tools List for the M18 computer system.
Historical Significance
The M18 Gun Direction Computer, commonly known as FADAC, was one of the U.S. Army’s early field-deployable digital computers. FADAC stands for Field Artillery Digital Automatic Computer.
The M18 processed battery, target, ammunition, meteorological, and other ballistic information to calculate firing data for cannon and rocket artillery. It became an important fire-direction tool for U.S. artillery units during the Vietnam era.
Programs were loaded into the computer’s rotating magnetic-disk memory from punched paper tape using the AN/GSQ-64 Signal Data Reproducer.
What This Manual Covers
This -20P publication identifies repair parts and special tools authorized for organizational maintenance of the M18 Gun Direction Computer with equipment.
The manual supports:
- Identification of organizational-maintenance repair parts
- Location of components through illustrated parts groups
- Cross-referencing of figure and item numbers
- Identification by Federal Stock Number or manufacturer’s part number
- Interpretation of source and maintenance codes
- Parts requisitioning and maintenance planning
- Identification of authorized special tools
The M18 incorporated a magnetic-memory assembly, power-supply assemblies, cooling blowers, electronic circuitry, and a removable control section containing the keyboard, control panel, and indicators.
Key Features
- Official publication number: TM 9-1220-221-20P
- Publication date: January 1969
- Equipment covered: M18 Gun Direction Computer, W/E
- Federal Stock Number: FSN 1220-448-0131
- Common designation: FADAC
- Full designation: Field Artillery Digital Automatic Computer
- Publication type: repair-parts and special-tools list
- Maintenance scope: organizational maintenance
- Application: cannon and rocket artillery fire direction
- Published by: Headquarters, Department of the Army
Why This Manual Matters
TM 9-1220-221-20P preserves the Army’s official parts terminology and maintenance-supply information for the M18 FADAC system. It helps identify the components and specialized tools required to support this early field artillery computer at the organizational level.
The publication also complements TM 9-1220-221-10, the operator’s manual for the M18, by concentrating on repair-parts identification and maintenance support rather than operating procedures.
About This Manual
Published by Headquarters, Department of the Army in January 1969, TM 9-1220-221-20P is the Organizational Maintenance Repair Parts and Special Tools List for the M18 Gun Direction Computer with equipment, FSN 1220-448-0131.
Ideal For
This manual is a strong fit for:
- U.S. Army technical-manual collectors
- Field artillery and fire-direction researchers
- Military-computer historians
- Vietnam-era artillery collections
- M18 FADAC restoration projects
- Military museums and reference libraries
- Repair-parts and special-tools manual collectors
Approx length 8", Approx width 10", Approx height .2", Approx weight 1lbs.
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