Fault Message:

GEN3 OPEN POR/FEED/GEN FAULT

Fault Code:

2423108LPS

Associated CAS:

GEN 3 FAIL
(Advisory)

Generator Control Unit (GCU) 3 has detected a failure (open circuit) associated with the Open POR/FEED/GEN circuit and consequently Generator 3 trips off-line. Inhibited during Take-Off and Landing.

• Generator Control Unit (GCU) 3 (A58)
• Variable Frequency Generator (VFG) 3 (G3)
• AC Power Center (ACPC) (A54)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

A GCU patch cable (GSE REF # 24X-24-02) can be used to swap GCUs 1, 4 and 5 into position 2 or 3 (for troubleshooting only).

The GCU NVMs can only be downloaded at position #2 or #3.

1. Swap GCU 3 with GCU 4 (physically or using the GCU patch cable). Is the fault still present?

   1. If YES, continue with next step.
   2. If NO, replace GCU 3 and do close out.

2. Disconnect connector GCU 3 (A58P1) and ACPC (A54P3). Perform a continuity check as follows:

   From	To	Result
   A58P1-A	Ground
   A58P1-B	Ground
   A58P1-C	Ground

   1. If there is continuity, repair defective wiring as required and do close out.
   2. If there is no continuity, continue with next step.

3. Perform a continuity check as follows:

   From	To	Result
   A58P1-A	A54P3-A
   A58P1-B	A54P3-B
   A58P1-C	A54P3-C

   1. If there is continuity, continue with next step.
   2. If there is no continuity, repair defective wiring as required and do close out.

4. Perform a continuity check as follows:

   From	To	Result
   VFG 3 Stud T1	ACPC VFG 3 Stud T7
   VFG 3 Stud T2	ACPC VFG 3 Stud T8
   VFG 3 Stud T3	ACPC VFG 3 Stud T9

   1. If there is continuity, continue with next step.
   2. If there is no continuity, repair defective wiring as required and do close out.

5. Disconnect ACPC studs T7, T8 and T9. Perform a continuity check as follows:

   From	To	Result
   VFG 3 stud T7	Ground
   VFG 3 Stud T8	Ground
   VFG 3 Stud T9	Ground

   1. If there is continuity, repair defective wiring as required and do close out.
   2. If there is no continuity, continue with next step.

6. Perform a continuity check on the ACPC as follows:

   From	To	Result
   A54P3-A	Ground
   A54P3-B	Ground
   A54P3-C	Ground

   1. If there is continuity, go to step 9.
   2. If there is no continuity, continue with next step.

7. Perform a continuity check on the ACPC as follows:

   From	To	Result
   A54P3-A	ACPC VFG 3 Stud T7
   A54P3-B	ACPC VFG 3 Stud T8
   A54P3-C	ACPC VFG 3 Stud T9

   1. If there is continuity, continue with next step.
   2. If there is no continuity, repair defective wiring as required and do close out.

8. Swap VFG 3 with VFG 4. Is the fault still present?

   1. If YES, continue with next step.
   2. If NO, replace VFG 3 and do close out.

9. Replace ACPC.
10. Do close out.