W DOC AIRBUS | TSM A320F

Electrical failure of the Alternate Brake Servovalve


TASK 32-43-00-810-803-A
Electrical failure of the Alternate Brake Servovalve


1. Possible Causes
  • SERVO VALVE N A 40GG EQ002DEQ0040GG [40GG]
  • BSCU [10GG]
  • wiring from the BSCU (10GG) to the alternate brake servovalve 40GG
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 31-32-00-869-002
Procedure for the Class 3 Fault Reading
AMM 32-42-27-400-001
Installation of the Brake
AMM 32-42-34-000-001
Removal of the Braking/Steering Control Unit (BSCU)
AMM 32-42-34-400-001
Installation of the Braking/Steering Control Unit (BSCU)
ASM 324301
AMM 32-43-27-000-001
Removal of the Alternate Brake Servovalve
AMM 32-46-00-740-001
BITE Test of the BSCU
3. Fault Confirmation
Subtask 32-43-00-740-054-A ** ON A/C NOT FOR ALL
A. Test
   (1) Do a reset of the BSCU with the A/SKID AND NOSE WHEEL switch (5GG).
   (2) Read the CLASS 3 FAULTS report AMM 31-32-00-869-002.
Subtask 32-43-00-740-054-C ** ON A/C NOT FOR ALL
A. Test
   (1) Do a reset of the BSCU with the A/SKID AND NOSE WHEEL switch (5GG).
   (2) Do the BITE test of the BSCU AMM 32-46-00-740-001.
4. Fault Isolation
Subtask 32-43-00-810-052-A ** ON A/C NOT FOR ALL
A. If the CLASS 3 FAULTS report gives the maintenance message BRK ALTN SERVOVALVE 40GG:
  • do a continuity/resistance test at the servovalve.
NOTE: The resistance must be between:
  • 90 and 100 ohms for P/N C20XXXXXX between the terminals A and C, (E and F) for coil B1, (B2).
  • 45 and 50 ohms for P/N E21XXXXXX between the terminals A and C, (A and F) for coil B1, (B2).
   (1) If the test is not OK:
   (2) If the test is OK:
     (a) If the fault continues:
  • do a check and repair the wiring from the BSCU (10GG) to the alternate brake servovalve 40GG pins AB/3A, 3B to pins A/C, A ASM 324301.
Subtask 32-43-00-810-052-B ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message BRK ALTN SERVOVLV(40GG):
  • do a continuity/resistance test at the servovalve.
NOTE: The resistance must be between:
  • 90 and 100 ohms for P/N C20XXXXXX between the terminals A and C, (E and F) for coil B1, (B2).
  • 45 and 50 ohms for P/N E21XXXXXX between the terminals A and C, (A and F) for coil B1, (B2).
   (1) If the test is not OK:
   (2) If the test is OK:
     (a) If the fault continues:
  • do a check and repair the wiring from the BSCU (10GG) to the alternate brake servovalve 40GG pins AB/3A, 3B to pins A/C, A ASM 324301.
Subtask 32-43-00-740-055-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.A.
[Rev.8 from Aug 2018] 2026.04.04 04:31:40 UTC