03/25/21
Message Overview:
Message Description:
Left ADC data bus (L-ADC-2) is reported absent by the left PFD, while the left MFD is not inactive and does not report the absence of L-ADC-2 data bus.
Possible Causes:
- Adaptive Flight-Display Unit 'A429 Input' (L PFD) (A27)
- Junction Box 3 (JB3)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Junction Box JB3 | AMM 24-63-09-000-802 |
| Installation of the Junction Box JB3 | AMM 24-63-09-400-802 |
| Removal of the Adaptive Flight-Display Unit | AMM 31-61-01-000-801 |
| Installation of the Adaptive Flight-Display Unit | AMM 31-61-01-400-801 |
| Removal of the Air Data Computer | AMM 34-13-01-000-801 |
| Installation of the Air Data Computer | AMM 34-13-01-400-801 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
| Electrical Connectors - Maintenance Practices - ALL | SPM 20-20-00-02 |
Troubleshooting Recommendations:
- Reset L PFD Circuit Breaker CB1-C3. Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Swap L PFD (A27) with L MFD (A29). Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Do wiring check between L PFD (A27), through JB3, and L MFD (A29) for the following wires:
From: To: Result: Conn. A27P1 - 10 Conn. A29P1 - 10 Conn. A27P1 - 11 Conn. A29P1 - 11 - If the check is not satisfactory, repair defective wiring or replace defective JB3.
- If the check is satisfactory, continue with next step.
- Do close out.