03/10/21
Message Overview:
Message Description:
A-DCU-5 bus is reported inoperative by Remote Data Concentrator (RDC) channel A, while A-DCU-5 is not reported inoperative by Data Concentrator Unit (DCU) channel B.
Possible Causes:
- Remote Data Concentrator (RDC) (A13)
- Junction Box 4 (JB4)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Junction Box JB4 | AMM 24-63-13-000-802 |
| Installation of the Junction Box JB4 | AMM 24-63-13-400-802 |
| Removal of the Remote Data Concentrator (RDC) | AMM 31-41-05-000-802 |
| Installation of the Remote Data Concentrator (RDC) | AMM 31-41-05-400-802 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset EICAS RDC A circuit breaker CB1-D2. Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Do wiring check between DCU (A14) and RDC (A13), through Junction Box 4 (JB4), for the following wires:
From To Result Conn. A14FP1-6A Conn. A13DP1-8A Conn. A14FP1-6B Conn. A13DP1-8B - If the check is satisfactory, continue with next step.
- If the check is not satisfactory, repair wiring or replace defective Junction Box 4.
- Replace RDC (A13).
- Do close out.