02/23/21
Message Overview:
Message Description:
SATCOM SDU-3/ SATCOM DL bus data absent at L-RIU and unit is strapped for data-link capability.
Possible Causes:
- SATCOM Satellite Data Unit (SDU)
- Left Radio Interface Unit (RIU) 1 (A17)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the SATCOM Satellite Data Unit (SDU) | AMM 23-15-01-000-801 |
| Installation of the SATCOM Satellite Data Unit (SDU) | AMM 23-15-01-400-801 |
| 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 |
| Standard Practices -Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset SATCOM (CB4-D2) circuit breaker.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Do wiring check of ARINC 429 data bus SDU-3 from SDU connector A82BP1 to RIU connector A17P2. Repair/replace as required.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace SDU.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace RIU 1.
- Do close out.