03/08/21
Message Overview:
Message Description:
No R-GPBUS-5 input to Data Concentrator Unit (DCU) B but data being received by at least 3-of (B-SPC, FCU, R-SECU, PSEU, HSTECU, FQGC).
Possible Causes:
- Data Concentrator Unit (DCU) (A14)
- 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 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 B Circuit Breaker CB2-D1. Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Do wiring check between DCU (A14) and IAPS Card Cage (A4), through Junction Box 4 for the following wires:
From To Result Conn. A14EP1-1A Conn. A4P101-1 Conn. A14EP1-1B Conn. A4P101-2 - If the check is satisfactory, continue with next step.
- If the check is not satisfactory, repair defective wire or Junction Box 4.
- Replace DCU (A14).
- Do close out.