TM 3-6665-209-35
CHAPTER 2
FIELD MAINTENANCE INSTRUCTIONS-THIRD ECHELON
Section I. CHASSIS GROUP
7. Chassis Assembly
switch S1 closes actuating the keying relay K2 through
the electron tube V1 thereby switching current from the
a. Description. The chassis assembly contains
ACCEPT light DS3 to the REJECT light DS4 and the
virtually all of the components of the indicator with the
electric bell DS5 if the bell switch S7 is closed. After
exception of the cabinet assembly, the panel cover
approximately six seconds, the switch contacts of the
assembly including the test probe assembly, and the
test cycle timer M2 open deenergizing the holding relay
accessories provided. All of the piping and wiring are
K1 which shuts off the power and completes the test
contained in the chassis assembly making the chassis
cycle.
assembly a self-contained unit which could be used
c. Maintenance.
Third echelon maintenance
without any other indicator components to conduct the
personnel are authorized to replace the rubber and
outlet leakage tests.
copper tubing, water manometer, nameplate, valve and
b. Functioning. (fig. 2). Outlet valves to be tested
blower adapter, various pipe fittings, rubber grommets,
are subjected to the test cycle accomplished within the
power cord, and the CALIBRATE knob shaft lock. They
chassis assembly. The test cycle functions as follows:
also are authorized to replace the electric bell (par. 8),
With power supplied to the electrical receptacle
fuse holder (par. 9), indicator lights (par. 10), balance
connector J3, the manual selector valve and the selector
orifice holder (par. 11), motor and pump assembly (par.
switch S8 placed in the proper mode (vacuum or
12), plug cocks, and air shutoff valve assembly (par. 13).
pressure), the mode switch S4 placed in the NORM
Third echelon maintenance personnel are authorized to
position, the LINE switch S6 and the PUMP switch S5
repair the cabinet assembly. Before installing a new or
placed in the ON position, the test cycle is begun by
rebuilt part, make certain it is clean and functions
pushing in on the VALVE fixture (or by closing the switch
properly. Use paint thinner, volatile mineral spirits, or
on the test probe assembly or the holding fixture) to
dry-cleaning solvent to clean dirt, grease, or oil from all
close the valve test switch S3. The interval timer M1 is
parts. Check electrical network for worn, frayed, or
energized as is the test cycle timer M2 and the holding
loose wire connections and for serviceability.
relay K1. Since the solenoid valve L3 is not energized,
pulsations from the pump are applied to the outlet valve
8. Electric Bell
3
under test. After 1 /4 seconds, the switch on the interval
timer M1 moves to the normally open side thereby
a. Description. The electric bell DS5 (25, fig. 3) is
energizing the solenoid valve L2 and permitting current
mounted on the underside of the chassis base. It is
to flow through the closed contacts of the keying relay
operated by a 6-volt, 60 cps, AC at 1.2 amperes power
K2 to light the ACCEPT light DS3. The solenoid valve
circuit from the bell transformer T2 (28). The electric bell
L4 shuts off the pump air and the solenoid valve L2
DS5 rings when the bell toggle switch S7 (22) is in the
opens permitting the test pressure or vacuum to be
on position and the REJECT light DS4 (8, fig. 4) lights.
applied to the outlet under test. If the leakage of the
The bell is a nonadjustable electric bell.
outlet valve exceeds the allowable limit. the diaphragm
AGO 8069A
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