W DOC AIRBUS | TSM A320F

Blank Screen on the CAPT ND DU

TASK 31-63-82-810-834-A
Blank Screen on the CAPT ND DU

1. Possible Causes
  • ND-CAPT [3WT1]
  • wiring
  • C/B-EIS/ND CAPT/SPLY [12WT1]
  • C/B-EIS/ND CAPT/SWTG [23WT1]
  • POT-ND, CAPT [8WT1]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 31-60-00-860-001
EIS Start Procedure
AMM 31-60-00-860-002
EIS Stop Procedure
ASM 316102
AMM 31-63-22-000-001
Removal of the Display Unit
AMM 31-63-22-400-001
Installation of the Display Unit
ASM 316801
ASM 316802
3. Fault Confirmation
Subtask 31-63-82-860-091-A ** ON A/C NOT FOR ALL
A. Job Set-up
   (1) Do the EIS start procedure AMM 31-60-00-860-001.
4. Fault Isolation
Subtask 31-63-82-810-103-A ** ON A/C NOT FOR ALL
A. If the operational image of the CAPT ND is shown on the screen
  • no maintenance action is necessary.
Subtask 31-63-82-810-104-A ** ON A/C NOT FOR ALL
B. If a maintenance message is shown on a black screen
  • do the fault isolation procedure relative to this message.
Subtask 31-63-82-810-105-A ** ON A/C NOT FOR ALL
C. If a blank screen (screen completely black) is shown on the CAPT ND DU:
   (1) If the fault continues:
     (a) Do a check for 115VAC at pin AA-79 of the CAPT ND DU ASM 316102.
       1 If there is no 115VAC:
  • check the wiring from the ND CAPT SPLY-C/B (12WT1) to the CAPT ND-DU(3WT1) pin AA-79.
         a If there is no continuity:
  • repair the wiring.
         b If there is continuity:
  • replace the C/B-EIS/ND CAPT/SPLY [12WT1] .
       2 If there is 115VAC:
  • do a check for a ground signal at pin A-77 of the CAPT ND DU.
         a If there is no ground signal:
  • check and repair the wiring from the CAPT ND-DU pin AA-77 to the the ground terminal.
         b If there is a ground signal:
  • do a check for 28VDC at the pin AA-81 of the CAPT ND DU
    . if there is no 28VDC, check and repair the wiring from the CAPT ND DU pin AA-81 to the CAPT ND-SWTG C/B (23WT1)
    . if there is 28VDC, replace the C/B-EIS/ND CAPT/SWTG [23WT1] .
   (2) If the fault continues:
  • do a check for a ground signal at pin AA-75 of the CAPT ND DU ASM 316802.
     (a) If there is a ground signal:
  • make sure there is no ground signal at pin 8 of the CAPT ND potentiometer (8WT1).
       1 If there is no ground signal:
  • check and repair the wiring from the CAPT ND-POT (8WT1) pin 8 to the CAPT ND-DU (3WT1) pin AA-75.
       2 If there is a ground signal:
  • replace the POT-ND, CAPT [8WT1] .
   (3) If the fault continues:
  • do a check and repair the wiring ASM 316801.
    from the CAPT ND-DU(3WT1) pin AA-39 to the CAPT ND-POT(8WT1) pin A2
    from the CAPT ND-DU(3WT1) pin AA-40 to the CAPT ND-POT(8WT1) pin A1
    from the CAPT ND-DU(3WT1) pin AA-36 to the CAPT ND-POT(8WT1) pin A3.
     (a) If the wiring is correct, replace the POT-ND, CAPT [8WT1] .
5. Close-up
Subtask 31-63-82-860-105-A ** ON A/C NOT FOR ALL
A. CLose-up
[Rev.8 from Aug 2018] 2026.04.04 04:31:16 UTC
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