Message Name:

NO A-RDC-3 BUS OUTPUT

Message Code:

B3-369046

Associated CAS:

None

Reporting LRU:	RDC A&B
System Description:	31-41-00
Schematic Diagram:	31-41-00
Wiring Diagram:	21-31-03 31-41-01 31-41-02 31-41-12 31-41-13

A-Remote Data Concentrator (RDC)-3 bus is reported failed by at least 3 of the Adaptive Flight-Display Units (AFD) and at least one Data Concentrator Unit (DCU) channel is receiving the Integrated Air System (IAS) Controller (IASC) data. IASC data is the only data transmitted on A-RDC-3 bus.

• Remote Data Concentrator (RDC) (A13)
• Junction Box 1 (JB1)
• Junction Box 3 (JB3)
• Primary Flight Display 1 (PFD) (A27)
• Primary Flight Display 2 (PFD) (A26)
• Multi-Function Display 1 (MFD) (A29)
• Multi-Function Display 2 (MFD) (A28)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Reset EICAS RDC A circuit breaker CB1-D2. Is the fault message still present?

1. If NO, do close out.
2. If YES, continue with next step.

2. Dowiring check from RDC (A13), through Junction Box 3 (JB3), to the 4 Adaptive Flight-Display units (A27, A29, A28, A26) for the following wires:

   From	To	Result
   Conn. A13FP1-4A	Conn. A27P2-19
   Conn. A13FP1-4B	Conn. A27P2-20
   Conn. A13FP1-4A	Conn. A29P2-19
   Conn. A13FP1-4B	Conn. A29P2-20
   Conn. A13FP1-4A	Conn. A28P2-19
   Conn. A13FP1-4B	Conn. A28P2-20
   Conn. A13FP1-4A	Conn. A26P2-19
   Conn. A13FP1-4B	Conn. A26P2-20

   1. If the check is satisfactory, continue with next step.
   2. If the check is not satisfactory, repair wiring or replace defective Junction Box 3.

3. Dowiring check from RDC (A13), through Junction Box 3 (JB3), to L IASC (A55) for the following wires:

   From	To	Result
   Conn. A13FP1-2A	Conn. A55P2-33
   Conn. A13FP1-2B	Conn. A55P2-6

   1. If the check is satisfactory, continue with next step.
   2. If the check is not satisfactory, repair wiring or replace defective Junction Box 3.

4. Remove L PFD (A27). Is the fault message still present\?

   1. If NO, replace defective Adaptive Flight Display unit.
   2. If YES, continue with next step.
      NOTE: An internal short circuit of the ARINC receiver could result in a transmission failure of the A-RDC-3 data bus.

5. Re-install L PFD (A27) and remove L MFD (A29). Is the fault message is still present?

1. If NO, replace defective Adaptive Flight Display unit.
2. If YES, continue with next step.
   NOTE: An internal short circuit of the ARINC receiver could result in a transmission failure of the A-RDC-3 data bus.

6. Re-install L MFD (A29) and remove R MFD (A28). Is the fault message is still present?

   1. If NO, replace defective Adaptive Flight Display unit.
   2. If YES, continue with next step.
      NOTE: An internal short circuit of the ARINC receiver could result in a transmission failure of the A-RDC-3 data bus.

7. Re-install R MFD (A28) and remove R PFD (A26). Is the fault message is still present?

   1. If NO, replace defective Adaptive Flight Display unit.
   2. If YES, continue with next step.
      NOTE: An internal short circuit of the ARINC receiver could result in a transmission failure of the A-RDC-3 data bus.

8. Re-install R PFD (A26) and replace RDC (A13).
9. Do close out.