04/08/21
Message Overview:
Message Description:
L-File Server Unit (FSU)-1 ARINC 429 data is reported absent at the Left Input/Output Concentrator (L IOC) and is also not present at the Left Multi-Function Display (L MFD).
Possible Causes:
- Left File Server Unit 1 (FSU 1) (A221)
- Left Input/Output Concentrator (L IOC) (A4-IOC1)
- Left Multi-Function Display (L MFD) (A29)
- Integrated Avionics Processing System (IAPS) Card Cage (ICC) (A4)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Integrated-Avionics Processor System (IAPS) Card Cage (ICC) | AMM 31-45-01-000-801 |
| Installation of the Integrated-Avionics Processor System (IAPS) Card Cage (ICC) | AMM 31-45-01-400-801 |
| Removal of the Input/Output Concentrator Unit (IOC) | AMM 31-45-05-000-801 |
| Installation of the Input/Output Concentrator Unit (IOC) | AMM 31-45-05-400-801 |
| 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 File Server Unit (FSU) | AMM 46-21-01-000-801 |
| Installation of the File Server Unit (FSU) | AMM 46-21-01-400-801 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset L FILE SERVER (CB1-C6) circuit breaker.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Ensure power and grounds are available at FSU 1.
28 VDC PWR GND Chassis GND A221P1-14 A221P1-47 A221P1-35 A221P1-67 A221P1-68 - If 28 VDC and grounds are available at FSU 1, go to step 4.
- If 28 VDC and/or grounds are not available at FSU 1, continue with next step.
- Do wiring check between FSU 1 connector A221P1 and circuit breaker CB1-C6 L FILE SERVER. Replace/repair as required.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Swap IOCs.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Swap MFDs.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Swap FSUs.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Do wiring check of the ARINC 429 L-FSU-1 data bus between FSU 1 connector A221P1 and IAPS connector A4P1. Replace/repair as required.
FSU 1 IAPS Expected Results Actual A221P1-91 A4P1-19 ≈0 Ω A221P1-92 A4P1-20 ≈0 Ω - If system checks are good, do close out.
- If fault remains, continue with next step.
NOTE: An internal short of any LRU connected to this ARINC data bus may cause the fault.
- Do wiring check of the Ethernet buses (transmit/receive) between FSU 1 connector A221P2 and L MFD connector A29P1. Replace/repair as required.
FSU 1 L MFD Expected Results Actual A221P2-D1 A29P1-41 ≈0 Ω A221P1-D3 A29P1-16 ≈0 Ω A221P2-D2 A29P1-18 ≈0 Ω A221P2-D4 A29P1-19 ≈0 Ω - If system checks are good, do close out.
- If fault remains, continue with next step.
NOTE: An internal short of any LRU connected to these data buses may cause the fault.
- Replace IAPS Card Cage (ICC).
- Do close out.