Description
Technical Manual Change 1 (TM 9-1240-286-35P) for M115/T197 Periscope Mount April 1961
Technical Manual Change 1 (TM 9-1240-286-35P) for M115/T197 Periscope Mount – April 1961
Item Overview
This original U.S. Army Change 1 publication updates TM 9-1240-286-35P, the field and depot maintenance repair-parts and special-tools list for the M115 Periscope Mount, formerly designated T197.
Change 1 was issued in April 1961. It applies to the original technical manual dated July 21, 1960.
This listing is for the Change 1 update only. It is not the complete July 1960 base manual and does not include the M115 mount, M31 periscope, tank, tools, or other fire-control equipment.
About the Original Manual
TM 9-1240-286-35P provided repair-parts and special-tools information for field and depot maintenance of the M115/T197 Periscope Mount. It helped maintenance personnel identify components and order authorized replacement parts.
The base manual covered information such as:
- Major assemblies and smaller repair parts
- Illustrated component identification
- Official part names and numbers
- Maintenance-level authorization
- Special-tools information
- Numerical parts indexes
- Supply and requisition references
M115/T197 Periscope Mount History
The T197 was the developmental designation for the mount standardized as the M115. It was designed to support and align the M31 gunner’s periscope within a tank fire-control system.
The mount secured the periscope and connected it with the ballistic-drive system. It also provided locking, release, and alignment functions needed to install and service the optic.
The M31 contained a magnified aiming channel and a wide-angle observation window. The M31 was the optical instrument, while the M115 served as its mechanical mounting and alignment assembly.
The system was associated with early M60-series tank fire control. The M115 mount was also documented with the M31 gunner’s periscope on the 90-mm M48A3 Patton tank.
Historical Significance
Issued less than a year after the original parts manual, this April 1961 change reflects the Army’s effort to keep early tank fire-control records accurate. It dates from a period when the M115 mount was moving from its T197 developmental identity into standard service.
Standalone change publications are often separated from their original manuals after installation. This example is useful for comparing different editions and assembling a complete M115/T197 technical-manual set.
Identification
- Publication: Change 1
- Manual number: TM 9-1240-286-35P
- Equipment: Periscope Mount M115
- Developmental designation: T197
- Change date: April 1961
- Original manual date: July 21, 1960
- Publication type: Field and Depot Maintenance Repair Parts and Special Tools List update
- Compatible optical equipment: M31 gunner’s periscope
- Documented vehicle family: M60 and M48A3 tanks
Ideal For
- U.S. Army technical-manual collections
- M60 and M48A3 tank research
- M115/T197 component identification
- M31 periscope restoration reference
- Cold War and Vietnam-era displays
- Collectors assembling a complete manual set
Approx length 8", Approx width 10", Approx height .1", Approx weight .1lbs.
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