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(WARNING)
RED MESSAGE (CAUTION)
AMBER MESSAGE (ADVISORY)
CYAN MESSAGE (STATUS)
WHITE MESSAGE Require immediate crew attention. These messages are accompanied by flashing master warning, triple chime attenson with or without voice message or dedicated tone. Require immediate crew awareness and future crew action may be required in the form of alternate system selection or performance limitation. These message are accompanied by flashing master caution and a single chime. Indicate safe or normal system operation which require crew awareness, over and above the dark cockpit philosophy. Indicate minor failures or reduction in systems capability, which require no crew action.

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Quick Links

03/04/21

Message Overview:

Message Name:

NO A-DCU-6 BUS OUTPUT

Message Code:

B3-006493

Associated CAS:

None

Reporting LRU: DCU 1
System Description: 31-41-00
Schematic Diagram: 31-41-00
Wiring Diagram: 31-41-01
31-41-02
31-52-03

Message Description:

No A-DCU-6 data received at Lamp Driver Unit.

Possible Causes:

  • Data Concentrator Unit (DCU) (A14)
  • Lamp Driver Unit (LDU) (A52)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Removal of the Data Concentrator Unit (DCU) AMM 31-41-01-000-802
Installation of the Data Concentrator Unit (DCU) AMM 31-41-01-400-802
Removal of the Lamp Driver Unit AMM 31-52-01-000-801
Installation of the Lamp Driver Unit AMM 31-52-01-400-801
Wiring - Maintenance Practices - ALL SPM 20-12-00-02
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02

Troubleshooting Recommendations:

  1. Reset EICAS DCU A Circuit Breaker CB1-D1 and ANNUNCIATOR CTRL 1 Circuit Breaker CB1-D3. Is the fault message still present?

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

  2. Do wiring check between DCU (A14), and LDU (A52) for the following wires:

    From To Result
    Conn A14FP1 - 7A Conn A52P1 - 75 (Note 1)
    Conn A14FP1 - 7B Conn A52P1 - 76 (Note 1)

    1. If the check is satisfactory, continue with next step.
    2. If the check is not satisfactory, repair wiring.
      NOTE 1: For Aircraft 20001 - 20124 Post STC ST01732LA-D or Post SB 100-46-06, the LDU connectors are identified "A52BP1" and "A52BP2".

  3. Replace DCU (A14). Is the fault message still present?

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

  4. Replace LDU (A52).
  5. Do close out.

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