TM 1–1520–238–T–3
17–2
Change 5
Personnel Required:
(2)
References:
TM 9–1230–476–20–2
Equipment Conditions:
Ref
Condition
TM 9–1230–476–20–2
MULTIPLEX SUBSYSTEM
– MAINTENANCE
OPERATIONAL CHECK in
progress
NOTE
All multiplex read code responses are read from right to
left.
Multiplex read codes must be used in conjunction with
applicable Maintenance Operational Check (MOC) in
progress.
Multiplex read codes are observed on the HOD (ADC) or
CDU (ADD).
MULTIPLEX READ CODE INTERPRETATIONS
17–1 SIGNAL NAME:
DEK TOGGLE BIT
MEMORY LOCATION: 000444
MEMORY DATA BIT(S):
4
(BINARY)
CONDITION:
(None)
SIGNAL FUNCTION:
Indicates DEK processor is operating.
REMARKS: From DEK through copilot/gunner (CPG) multiplex remote terminal unit (MRTU) Type III
to fire control computer (FCC). Monitors DEK processor.
PASS:
If sixth digit on heads out display (HOD) changes state from 1 to 0, 0 to 1 every 25 HZ, go to
paragraph 17–2.
FAIL: Location of fault: freezes at one state (1 or 0) for more than two 25 HZ frames. CPG
transformer, wiring from CPG transformer to DEK, DEK,wiring from DEK to CPG MRTU Type
III, CPG MRTU Type III. Troubleshoot wiring to isolate fault (TM 9–1230–476–20–2).
17–2 SIGNAL NAME:
DEK SWITCH
MEMORY LOCATION: 000444
MEMORY DATA BIT(S):
8–11
(HEX)
CONDITION:
If fourth digit displayed on HOD is 0=STBY
If fourth digit displayed on HOD is 1=RANGE
If fourth digit displayed on HOD is 2=FD/LS
If fourth digit displayed on HOD is 3=(NOT USED)
If fourth digit displayed on HOD is 4=TGT
If fourth digit displayed on HOD is 5=CODE
If fourth digit displayed on HOD is 6=SP1
If fourth digit displayed on HOD is 7=OFF
SIGNAL FUNCTION:
Monitors position of DEK DATA ENTRY switch.
REMARKS: From DEK through CPG MRTU Type III to FCC. Selects operating mode for fire control
system.
PASS:
If CONDITION corresponds to proper mode for switch position selected, go to
paragraph 17–3.
FAIL: Location of fault: DEK, wiring from DEK to CPG MRTU Type III, CPG MRTU Type III.
Troubleshoot wiring to isolate fault (TM 9–1230–476–20–2).
