Thales 421 - Fault on Monitor Subassemblies

LLZ 421
Operation and Maintenance Fault Location
ILS 420
6−25Ed. 01.10
SOAC
Step Fault (cont.) A B C
9 CLR SDM
Alarm and/or
CLR DDM
Alarm
Check in PC user program
dialog Audio Generator Data
against Reference Data.
If deviations change LG−A, if
not go to C.
Check CLR CSB measure-
ments of RF Power Amplifier
Data against Reference Data.
If deviations change CLR
MODPA, if not go to C.
Check antenna system in-
cluding cables from/to.
10 Morse Code
Alarm
Check in PC user program
dialog Audio Generator Data
against Reference Data. If
deviations change LG−A, if
not go to B.
Check 1020 Hz AM CSB mea-
surements of RF Power Ampli-
fier Data against Reference
Data.
If deviations change LG−A, if
not go to C.
Check Backpanel for cor-
rect wiring and replace
backpanel if defective.
6.5.3.3 Fault on Monitor Subassemblies
Step Fault A B C
1 Integrity Fail
Indication
(ECU)
a) Integrity Fail Monitor 1
b) Integrity Fail Monitor 2
If a) and not b) go to C.
If b) and not a) go to C.
If a) and b) go to 2.
Replace the LG−M board
showing the Integrity Fail
condition.
2 Integrity Fail of
both Monitors
Change Main Transmitter and
if no Integrity Fail indicated,
change LG−A of the transmit-
ter being now in Standby
mode,
If Integrity Fail again go to B.
Change ECU board and check
again.