Section II. DESCRIPTION AND DATA
test-set-container storage compartments. The test set
container is discussed further in paragraph 1-10 and the test
set chassis assembly, in paragraph 1-11.
a. The test set is used during alignment, boresighting,
and test of a model XM12801- a model XM136 helmet sight
s u b s y s t e m (HSS); HSS XM128 is used in an
1-10. Test Set Container.
AH-1Q/AH-1S(Mod) Cobra Helicopter and HSS XM136, in
an AH-1S Cobra Helicopter. As shown in figure 1-1, the test
All other test set items are stored in the test set
set is made up of a test set subassembly, a linkage
container. Except for the test set chassis assembly, which is
orientation device (LOD), a helmet boresight tool, a circuit
screw-mounted in the bottom part of the container, the
card extractor, a connector shorting assembly, and four
other test set items are stored in the top part (the lid) of
cable assemblies; these items are discussed in detail in
the container. (Figure 1-1 shows the container open and
paragraphs 1-9 through 1-16.
indicates the storage compartments in the container lid;
figure 1-2 shows the closed container). The container is
b. As covered in detailed procedures in TM
aluminum and is equipped with carrying handles, four clasp
9-1270-212-14&P, the test set is used not only for
fasteners to secure the lid to the bottom section, and
alignment and bolesighting of the HSS but also for
slip-out hinges to permit removal of the lid during
complete electrical testing, isolating and verifying
operation. A seal between the lid and the bottom section
equipment failures that are detected by the built-in-test
insures that the container is airtight when the two sections
(BIT) circuits in the HSS EIA. The test set is used to test
are closed and secured. An air-bleed valve on the side of the
the EIA and the two linkages as a system or us separate
container is depressed to equalize the container internal
items, as well as the helmet sight assembly. It can also be
pressure and the external pressure. This valve must be
used to test individual subassemblies of the EIA after they
depressed before an attempt is made to open the container.
are removed from the EIA; separate tests are provided in
TM 9-1270-212-14&P for buffer amplifier modules A1
1-11. Test Set Chassis Assembly.
through A8 and for circuit card assemblies A9 thlough A13
and A15. The only EIA subassembly that cannot be tested
The test set chassis assembly, mounted in the bottom of
as a separate item is azimuth bias circuit card assembly A14
the test set container (fig. 1-1), has an aluminum control
in the EIA for XM136; this circuit card assembly does not
panel on which are mounted all the controls, indicators,
exist in the EIA for XM128.
and connectors. Inside the chassis are the other electrical
components, including the two circuit card assemblies, A2
and A12, which are mounted on brackets secured to the
back of the control panel.
In an EIA from XM128, the logic circuit card
assembly has a designation of A10 versus a
designation of A15 in an EIA from XM136.
a. The LOD is used to align the gunner and pilot linkage
assemblies. The LOD consists of a leveling base to which is
1-9. Test Set Subassembly.
attached a bubble level assembly, a bubble level reflector, a
rail clamp base assembly, an alignment pin, a magnet, a
The test set subassembly consists of two main items,
magnet adjustment device, and a borescope angle bracket.
which are the test set chassis assembly and the test set
container, and two plates, which are the test set instruction
b. The bubble level assembly is used to check the
plate and the test set identification plate. The test set
alignment of the linkage rails after the level assembly has
chassis assembly is mounted in the bottom part of the test
been properly adjusted on the telescopic sighting unit
set container, as shown in figure 1-1, but may be removed
(TSU) boresight device. The bubble level reflector enables
and mounted in an electrical-equipment rack. The test set
the operator to check the bubble level from an angle. The
identification plate is mounted on the top (front panel) of
rail clamp base assembly has deep parallel grooves in the
the test set chassis assembly. The test set instruction plate,
base surface that are designed to fit up against the linkage
which states the part numbers of the HSS items which can
be tested with the test set, is mounted on the cover for the