TM 55-4920-231-14
b. Perform the before operation services listed
and check the valves for operation and defects.
in the operator's daily service (paragraph 54).
e. Release the fasteners to open the rear access
panel and inspect for defects, evidence of leak-
age, and the operation of the reservoir selector
Inspect a used tester in the same manner as
valve.
a new one (paragraph 7) with special emphasis
f. Perform the inspections specified in the be-
on inspection for worn parts. Correct deficiencies
fore operation services of the operator's daily
noted or report them to the proper authority.
service (paragraph 54).
A used tester is serviced in the same manner
Perform the following services before opera-
as new equipment (paragraph 8). However, spe-
ting the tester:
cial emphasis should be placed on the before
operation services and lubrication details for a
a. Lubricate in accordance with instructions
tester which has previously been in use.
contained in paragraphs 51 and 52.
Section II. CONTROLS AND INSTRUMENTS
functions as a single control manifold and pro-
11. GENERAL.
vides various vacuum-pressure systems required
This section describes, locates, illustrates, and
to kit and/or calibrate certain types of aircraft
furnishes the operator with sufficient informa-
instruments.
tion pertaining to the various controls and in-
struments provided for the proper operation of
the equipment.
The PRESSURE selector knob (10, figure 7)
12. POWER SWITCH.
has five. positions and operates a valve which
functions as a single control manifold and pro-
The double pole, double throw, toggle-type
vides various vacuum, pressure, and vacuum-
power switch (14, figure 7) has an OFF position
pressure systems required to test and/or calibrate
which opens the circuit and shuts off the elec-
certain types of aircraft instruments.
trical power supply to the tester. The ON posi-
tion (away from operator) is in the opposite di-
rection of the OFF position (toward the opera-
tor) and closes the circuit to provide electrical
Counterclockwise rotation of pressure DE-
current to the tester when the power source is
CREASE knob (19, figure 7) from closed posi-
connected.
tion opens a needle valve allowing system pres-
sure to bleed off.
13. INDICATOR LIGHT.
The indicator light (13, figure 7) illuminates
when the power circuit in the tester is operating.
Counterclockwise rotation of pressure IN-
CREASE knob (12, figure 7) from closed posi-
tion opens a needle valve allowing pressure in
The 28 vdc, 3 amp cartridge fuse (16, figure
system to increase.
7) provides protection against an excessive flow
of current which would damage the electrical
system.
Counterclockwise rotation of vacuum DE-
CREASE knob (19, figure 7) from closed posi-
The spare cartridge fuse (,15, figure 7) is pro-
tion opens a needle valve which permits system
vided to replace the cartridge fuse (16) when it
vacuum to bleed off.
has blown.
Counterclockwise rotation of vacuum IN-
The VACUUM selector knob (20, figure 7)
CREASE knob (17, figure 7) opens a needle
has five positions, and operates a valve which
valve and provides increased vacuum in system.
