Message Name:

NO R-HF-1 BUS OUTPUT

Message Code:

B3-006834

Associated CAS:

None

R-HF-1 bus data absent at R-RIU.

• Right HF Transceiver (HF 2) (A62)
• Right Radio Interface Unit (RIU 2) (A18)
• Right HF Remote-Control Circuit Breaker (RCCB) Contactor (K108)
• Right HF Current Thermal Sensor (RT4)
• HF 2 DC Circuit Breaker (CB2-B3)
• Right Cockpit Circuit Breaker Panel (CCBP2)
• Right DC Power Center (R DCPC) (A36)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Reset HF 2 Circuit Breaker CB2-B3, RIU 2B/AURAL Circuit Breaker CB2-B5 and RIU 2A Circuit Breaker CB2-B4. Is the fault message still present?

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

2. Swap right HF Transceiver (A62) with left HF Transceiver (A61). Is the fault message still present?

   1. If YES, continue with next step.
   2. If NO, replace defective HF Transceiver.

3. Swap right RIU (A18) with left RIU (A17). Is the fault message still present?

1. If YES, continue with next step.
2. If NO, replace defective HF Transceiver.

4. Swap right HF RCCB Contactor (K108) located in the R DCPC (A36) with left HF RCCB Contactor (K109) located in the L DCPC (A35). Is the fault message still present?

   1. If YES, continue with next step.
   2. If NO, replace the defective RCCB Contactor.

5. Swap right HF Current Thermal Sensor (RT4) located in the R DCPC (A36) with left HF Current Thermal Sensor (RT3) located in the L DCPC (A35). Is the fault message still present?

   1. If YES, continue with next step.
   2. If NO, replace the defective Current Thermal Sensor.

6. Do wiring check between the right HF Transceiver (A62) and right RIU (A18) for the following wires:

   From	To	Result
   Conn. A62P1 - m	Conn. A18P1 - 61
   Conn. A62P1 - AA	Conn. A18P1 - 62

   1. If the check is satisfactory, continue with next step.
   2. If the check is not satisfactory, replace defective wiring.

7. Check presence of the ground at the right HF Transceiver (A62).

   Measurement at	Expected Result	Result
   Conn. A62P4 - E	Aircraft Ground (pwr gnd)
   Conn. A62P4 - F	Aircraft Ground (pwr gnd)
   Conn. A62P4 - G	Aircraft Ground (pwr gnd)
   Conn. A62P4 - H	Aircraft Ground (pwr gnd)
   Conn. A62P4 - K	Aircraft Ground (pwr gnd)
   Conn. A62P1 - e	Aircraft Ground (chassis gnd)
   Conn. A62P1 - V	Aircraft Ground (chassis gnd)
   Conn. A62P1 - FF	Aircraft Ground (chassis gnd)
   Conn. A62P1 - HH	Aircraft Ground (chassis gnd)

   1. If the check is satisfactory, continue with step next step.
   2. If the check is not satisfactory, repair the defective wiring.

8. Check presence of the 28 VDC at the right HF Transceiver (A62).

   Measurement at	Expected Result	Result
   Conn. A62P4 - A	28 VDC (pwr)
   Conn. A62P4 - B	28 VDC (pwr)
   Conn. A62P4 - C	28 VDC (pwr)
   Conn. A62P4 - D	28 VDC (pwr)
   Conn. A62P4 - J	28 VDC (pwr)

   1. If the check is satisfactory, do close out.
   2. If the check is not satisfactory, continue with next step.

9. Do wiring check between the right HF Transceiver (A62) and right DCPC (A36) for the following wires:

   From	To	Result
   Conn. A62P4 - A	Conn. A36P4 - 25
   Conn. A62P4 - B	Conn. A36P4 - 25
   Conn. A62P4 - C	Conn. A36P4 - 25
   Conn. A62P4 - D	Conn. A36P4 - 25
   Conn. A62P4 - J	Conn. A36P4 - 25

1. If the check is satisfactory, continue with next step.
2. If the check is not satisfactory, replace defective wiring.

10. Check proper operation of the HF 2 control input at the R DCPC (A36).

    HF 2 CB2-B3 Status	Measurement at	Expected result	Result
    Closed	Conn. A36P4 - 31	Ground
    Open	Conn. A36P4 - 31	Infinite Resistance

    1. If the check is satisfactory, continue with step 13.
    2. If the check is not satisfactory, continue with next step.

11. Do wiring check between the right Cockpit Circuit Breaker Panel (CCBP2) and right DCPC (A36) for the following wires:

    From	To	Result
    Conn. CBP2J1 - 11	Conn. A36P4 - 31
    Conn. CBP2J1 - 12	Aircraft Ground

    1. If the check is satisfactory, continue with next step.
    2. If the check is not satisfactory, replace defective wiring.

12. Replace HF 2 Circuit Breaker CB2-B3. Is the fault message is still present?

1. If NO, do close out.
2. If YES, replace defective right Cockpit Circuit Breaker Panel (CCBP2).

13. Replace right DCPC (A36).
14. Do close out.