TM 1–1520–238–T–3
Change 4
17–3/(17–4 blank)
17–3 SIGNAL NAME:
DEK DATA VALID
MEMORY LOCATION: 000444
MEMORY DATA BIT(S):
7
(BINARY)
CONDITION:
(None)
SIGNAL FUNCTION:
Indicates whether keyboard entry is valid and to be read by FCC or keyboard
entry is invalid and to be ignored.
REMARKS: From DEK through CPG MRTU Type III to FCC. This bit identifies erroneous DEK data
words.
PASS:
If fifth digit on HOD is 1, 3, 5, or 7, go to paragraph 17–4.
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).
17–4 SIGNAL NAME:
DEK DATA VALID TO TEU (ACY) DEK DATA VALID CMD (ACZ)
MEMORY LOCATION: 001223
MEMORY DATA BIT(S):
4
(BINARY)
CONDITION:
(None)
SIGNAL FUNCTION:
Indicates whether keyboard entry is valid and to be read by target acquisition
designation sight (TADS) electronic unit (TEU) or the keyboard entry is invalid
and to be ignored.
REMARKS: From FCC through left–hand forward avionics bay (LH FAB) MRTU Type I to TEU. This
bit identifies erroneous DEK data words. Check for TYPE I MRTU NO–GO LH FAB
FD/LS message.
PASS:
If sixth digit on HOD is 1, go to paragraph 17–5.
FAIL: Location of fault: LH FAB MRTU Type I, wiring from LH FAB MRTU Type I to TEU, TEU, FCC.
Troubleshoot wiring to isolate fault (TM 9–1230–476–20–2).
17–5 SIGNAL NAME:
DEK DATA
MEMORY LOCATION: 000444
MEMORY DATA BIT(S):
12–19
(ASCII)
CONDITION:
Refer to Table 17–1 for ASCII code conversions.
SIGNAL FUNCTION:
Provides DEK characters in 8–bit ASCII word format to FCC.
REMARKS: From DEK through CPG MRTU Type III to FCC.
PASS:
If ASCII conversion results correspond to the key pressed on DEK, go to paragraph 17–6.
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).
17–6 SIGNAL NAME:
DEK DATA TO TEU (ACY) DEK DATA (ACZ)
MEMORY LOCATION: 001223
MEMORY DATA BIT(S):
5–11
(ASCII)
CONDITION:
Refer to Table 17–1 for ASCII code conversions.
SIGNAL FUNCTION:
Provides DEK characters in 8–bit ASCII word format to TEU.
REMARKS: From FCC through LH FAB MRTU Type I to TEU. The ASCII conversion for memory data
bits 5–11 is the same as for memory data bits 12–19, paragraph 17–5. Check for TYPE I
MRTU NO–GO LH FAB FD/LS message.
PASS:
If ASCII conversion is identical to results in paragraph 17–5, go to Chapter 15,
paragraph 15–151.
FAIL: Location of fault: LH FAB MRTU Type I, wiring from LH FAB MRTU Type I to TEU, TEU, FCC.
Troubleshoot wiring to isolate fault (TM 9–1230–476–20–2).
