TM 55-4920-414-13&P
Section Il. TROUBLESHOOTING
4-3. scope.
a. This section contains troubleshooting or malfunction in-
formation and tests for locating and correcting most of the trou-
bles which may develop in either the Test Box or the Test
Fixture. Each malfunction or trouble symptom for an individu-
al component, unit, or system is followed by a list of tests or
inspections necessary for you to determine probable causes and
corrective actions for you to remedy the malfunction.
b. This manual cannot list all possible malfunctions that may
occur or all teats or inspections and corrective actions. If a mal-
function is not listed (except when malfunction and cause are
obvious), or is not corrected by listed corrective actions, you
should notify higher level maintenance. You should do the
tests/inspections and corrective actions in the order listed.
4-4. Troubleshooting Test Box.
Table 4-2 lists the common malfunctions that you may find
during the operation or maintenance of the Test Box. Before
attempting troubleshooting, do the following test setup.
a. Pull out POWER DC and AC circuit breakers.
b. Place TRIM, POWER AC, and POWER DC switch OFF.
Place SAS and BOOST switches ON.
c. Remove ac and dc power cables from cable stowage com-
partment at rear of Test Box, and mate with appropriate con-
nectors (J1 and J2) at front panel.
d. Connect power cables to source of 115 vac, 60 Hz and 28
vdc power.
4-5. Troubleshooting loot Fixture.
Table 4-3 lists the common malfunctions that you may find
during the operation or maintenance of the Test Fixture. Con-
nect Test Fixture and Test Box as indicated in paragraph 3-3.
Do this test setup:
Position Teat Fixture on bench so that relief valve
cannot vent on personnel during overpressure con-
ditions.
Make certain that hydraulic test stand uses hy-
draulic fluid consistent with each operating en-
vironment.
a. On Test Box place all switches OFF.
b. Place TRIM COIL SELECT switch to BOTH.
c. On Test Fixture manifold, install 0-4000 psi hydraulic pres-
sure gages in BOOST and TRIM pressure outlet ports.
d. Push in POWER AC and DC circuit breakers.
NOTE
Wipe all hydraulic fittings dry of surface fluid.
4-2
