Loss of the Signal from the Tachometer (Wheel 3) to the BSCU

TASK 32-42-00-810-821-A
Loss of the Signal from the Tachometer (Wheel 3) to the BSCU

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 32-41-11-000-006	Removal of the MLG Wheel
AMM 32-41-11-400-006	Installation of the MLG Wheel
AMM 32-42-00-720-002	Functional Test of the Tachometers and the Anti-Skid System with the Normal Braking System ON
AMM 32-42-00-720-003	Functional Test of the tachometers with the AIDS.
ASM 324202
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)
AMM 32-42-57-000-001	Removal of the Tachometer
AMM 32-42-57-400-001	Installation of the Tachometer
AMM 32-42-68-000-003	Removal of the MLG Tachometer-Drive
AMM 32-42-68-400-003	Installation of the MLG Tachometer-Drive

3. Fault Confirmation
Subtask 32-42-00-720-062-A

A. Test
Do the functional test of the tachometer AMM 32-42-00-720-002 or AMM 32-42-00-720-003

4. Fault Isolation
Subtask 32-42-00-810-070-A

A. If the test does not confirm the fault:
(1) Do a visual inspection of the tachometer drive mechanism and make sure that:

The tachometer drive shaft moves freely.
The splines of the tachometer drive shaft are in the correct condition.
The splines of the tachometer hubcap or the splines of the debris guard (if brake fans are installed) are in the correct condition.

NOTE: The functional test of the tachometer can be correct although the splines are worn.

(2) If the tachometer drive is damaged:

Replace the DRIVE ASSY-TACHOMETER,WHEEL 3 [2679GM] AMM 32-42-68-000-003 and AMM 32-42-68-400-003.

(3) If the tachometer hubcap or the debris guard (if brake fans are installed) is damaged:

Replace the tachometer hubcap or the debris guard of the MLG wheel AMM 32-41-11-000-006 and AMM 32-41-11-400-006.

Subtask 32-42-00-810-248-A

B. If the test confirms the fault:
(1) Do a visual inspection of the tachometer drive mechanism and make sure that:

The tachometer drive shaft moves freely and the splines of the tachometer drive shaft are in the correct condition.
The splines of the tachometer hubcap or the splines of the debris guard (if brake fans are installed) are in the correct condition.

(a) If the tachometer drive shaft is damaged or the splines of the tachometer drive shaft are not in the correct condition:

Replace the DRIVE ASSY-TACHOMETER,WHEEL 3 [2679GM] AMM 32-42-68-000-003 and AMM 32-42-68-400-003.

(b) If the tachometer hubcap or the debris guard (if brake fans are installed) is damaged:

Replace the tachometer hubcap or the debris guard of the MLG wheel AMM 32-41-11-000-006 and AMM 32-41-11-400-006.

(2) If the fault continues:

Do a check of the wiring ASM 324202 between:
. Pin A/A of the TACHOMETER-WHEEL 3 [20GG] and pin AB/7K of the BSCU [10GG]
. Pin A/C of the TACHOMETER-WHEEL 3 [20GG] and pin AB/7J of the BSCU [10GG]

(a) If the wiring is not correct:

(b) If the wiring is correct:

Subtask 32-42-00-720-063-A

C. Do the functional test given in Para. 3.A.

[Rev.8 from Aug 2018] 2026.04.04 04:31:32 UTC