03/04/21
Message Overview:
Message Description:
No LB-RIU-6 bus input at A-DCU and LB-RIU-6 is present at L-MFD and L-CDU.
Possible Causes:
- Data Concentrator Unit (DCU) (A14)
- Junction Box 3 (JB3)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Radio Interface Unit (RIU) | AMM 23-51-21-000-801 |
| Installation of the Radio Interface Unit (RIU) | AMM 23-51-21-400-801 |
| 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 Data Concentrator Unit (DCU) | AMM 31-41-01-000-802 |
| Installation of the Data Concentrator Unit (DCU) | AMM 31-41-01-400-802 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset EICAS DCU A Circuit Breaker CB1-D1. Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Dowiring check between DCU (A14) and RIU 1 (A17), through Junction Box 3, for the following wires:
From To Result Conn. A14DP1 - 6A Conn. A17P2 - 31 Conn. A14DP1 - 6B Conn. A17P2 - 32 - If the check is satisfactory, continue with next step.
- If the check is not satisfactory, repair defective wire or Junction Box 3.
- Replace DCU (A14).
- Do close out.