06/25/19
Message Overview:
Fault Message:
GCU1 [OPEN CIRCUIT TR4]
Fault Code:
2421106LPS
Associated CAS:
| Reporting LRU: | Generator Control Unit (GCU) 1 |
| System Description: | 24-21-00 |
| Schematic Diagram: | 24-21-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wiring Diagram: | 24-21-01 [ Global Express ] [ G5000 ] [ Global XRS ] |
Fault Description:
Generator Control Unit (GCU) #1 has detected a failure (open circuit) associated with Transistor 4 (TR4), consequently resulting in Generator #1 to tripped off-line or not come online.
Possible Causes:
- Generator Control Unit (GCU) 1 (A56)
- Variable Frequency Generator (VFG) 1 (G1)
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
The GCU NVMs can only be downloaded at position #2 or #3.
A GCU patch cable (GSE REF # 24X-24-02) can be used to swap GCU 1, GCU4 and APU GCU into position 2 or 3 (for troubleshooting only)
Quick Links:
| Removal of the Variable Frequency Generators (VFG) | AMM 24-21-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Variable Frequency Generators (VFG) | AMM 24-21-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Generator Control Units (GCU) | AMM 24-24-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Generator Control Units (GCU) | AMM 24-24-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
Troubleshooting Recommendations:
- Do a complete aircraft power reset. Is the fault still present?
- If YES, continue with next step.
- If NO, monitor for failure and do close out.
- Swap GCU 1 with GCU 2 (Physically or using the GCU patch cable).
- If system checks are good, replace GCU 1 and do close out.
- If fault remains, continue with next step.
- Replace GCU 1.
- Do close out.