Fault Message:

ACPC XFORMER/BRIDGE RECTIFER-T1-CR1

Fault Code:

2451368ACP

Associated CAS:

ELEC SYS FAULT
(Advisory)

Fault message is triggered if External AC is AVAIL but there is no 28 V Transformer (T1)/Rectifier (CR1) output detected by the AC-to-DC Converter Card. The output voltage is measured at D4 on Electronic Module (EM) 1 and D8 on EM2.

• AC Power Center (ACPC) Contactor (K1)
• Electronic Module (EM1)
• Electronic Module (EM2)
• Electronic Module (EM3)
• Transformer (T1)
• Bridge Rectifier (CR1)
• External AC/DC Converter Card
• AC Power Center (ACPC) (A54)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Remove Power from the Aircraft.
2. Access ACPC primary logic assembly. Disconnect Electric module 3. Perform a continuity check as follows:

   From	To	Result
   P503-7	Ground
   P503-8	Ground
   P503-9	Ground

   1. If there is no continuity, go to step 4.
   2. If there is continuity, continue with next step.

3. Disconnect K1 contacts A3, B3 & C3. Perform a continuity check as follows:

   From	To	Result
   P503-7	Ground
   P503-8	Ground
   P503-9	Ground

   1. If there is continuity, repair defective wiring as required if the short comes from outside the ACPC or replace the ACPC if the short comes from inside the ACPC and do close out.
   2. If there is no continuity, replace K1 and continue with next step.

4. Perform a continuity check as follows:

   From	To	Result
   P503-7	K1-A3
   P503-8	K1-B3
   P503-9	K1-C3

   1. If there is no continuity, go to step 12.
   2. If there is continuity, continue with next step.

5. Perform a continuity check across EM3 as follows:

   From	To	Result
   J503-7	J503-1
   J503-8	J503-2
   J503-9	J503-3

   1. If there is no continuity, replace EM3 and do close out.
   2. If there is continuity, continue with next step.

6. Disconnect EM1 and EM2 connectors (P407 & P206). Perform a continuity check as follows:

   From	To	Result
   P407-13	Ground
   P407-14	Ground

   1. If there is continuity, go to step 12.
   2. If there is no continuity, continue with next step.

7. Perform a resistance check on EM1 & EM2 as follows:

   From	To	Ω	Result
   J407-13	J407-4	5.62 KΩ
   J407-14	J407-4	5.62 KΩ
   J206-14	J206-4	5.62 KΩ

   1. If the diodes are not serviceable, replace defective EM and do close out.
   2. If the resistance values are correct, continue with next step.

8. Perform a diode check on EM1 & EM2 as follows:

   From	To	Result
   J407-14	J407-8
   J206-14	J206-8

   1. If the diodes are not serviceable, replace defective EM and do close out.
   2. If the diodes are serviceable, continue with next step.

9. Remove the EXT AC/DC Converter card. Perform a continuity check as follows:

   From	To	Result
   P407-4	Ground
   P206-4	Ground

   1. If there is continuity, go to step 12.
   2. If there is no continuity, continue with next step.

10. Perform a continuity check as follows:

    From	To	Result
    P407-4	P520A-9
    P206-4	P520C-30

    1. If there is continuity, continue with next step.
    2. If there is no continuity, go to step 12.

11. Replace EXT AC/DC Converter card.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

12. Replace ACPC.
13. Do close out.