ARMY TM 5-6675-308-34
MARINE CORPS TM 08837A-34/2
Table 4-14. IMU Testing, Alignment, anti Troubleshooting -- Continued
Malfunction
indication/corrective action
Test procedure
Normal indication
Ensure IMU is oriented to 45 10
degrees to any cardinal heading and
the azimuth is correct. Type RDY.
TTY will request a new measure-
ment of the last horizontal angle
followed by azimuth entry
TTY prints:
TYPE ONE OF: ACC REP BYP
ALIGNMENT HALTED:
Type REP and repeat theodolite
test. If test fails a second time,
replace the porro prism assembly
TTY prints:
THEODOLITE READING IN-
NOTE
CONSISTENT
A complete table of calibration pa-
TYPE ONE OF: REP,BYP
rameters, i n c l u d i n g the cal data
checksum, will print during subtest
Before using the theodolite readings
10. A failure table will print after
to calculate the porro prism cali-
test 10 results. OK means the param-
bration constants, several feasibil-
e t e r was within tolerance; OOC
ity checks will be run on the read-
means the parameter was out of tol-
ings. If one or more readings were
erance but has been recalibrated;
in error, these checks will detect
FAIL means the parameter was out
an inconsistency and give the op-
of tolerance and must be corrected
erator the option of repeating the
at the depot level.
readings or bypassing the test. If
an inconsistency is detected for
three consecutive sets of readings,
the system will assume that PADS
is in error and will print out an
IMU failure. Return I MU to depot
if any lines 1020 thru 1025 indi-
cate a failure. If only line 101 or
102 indicates a failure, replace the
p o r r o prism assembly. Return
IMU to depot if following test 9,
TTY prints: NEED DEPOT CAL
At end of test, TTY prints:
ALIGNMENT
COMPLETED
ooOOOoooOOOo
EXECUTE switch-indicator goes off
Press EXECUTE switch-indica-
tor to off
P A D S ON/OFF switch-indicator
Sequentially press PADS ON/
goes off
OFF switch-indicator and EN-
TER switch
System shuts down
Change 5
4-90
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