Main Start Contactor failed open (APS 3200)

TASK 49-00-00-810-989-A
Main Start Contactor failed open (APS 3200)

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ESPM 2052210
ESPM 2053210
AMM 49-00-00-710-008	Operational Test of the APU
ASM 494201
AMM 49-42-51-000-007	Removal of the Starter Motor (APS 3200)
AMM 49-42-51-400-007	Installation of the Starter Motor (APS 3200)
AMM 49-42-55-000-001	Removal of the Start Contactors
AMM 49-42-55-400-001	Installation of the Start Contactors

3. Fault Confirmation
Subtask 49-00-00-710-388-A ** ON A/C NOT FOR ALL

A. Do the operational test of the APU AMM 49-00-00-710-008.

4. Fault Isolation
Subtask 49-00-00-810-363-B ** ON A/C NOT FOR ALL

A. Maintenance Action
(1) If the APU Last Leg Report gives the maintenance message:

CONTACTOR 5KA
Fault Code Number: 128

do a check and repair of the wiring between ECB (59KD) AB/J10 and STARTER MOTOR (8KA) positive terminal ASM 494201 ESPM 2052210 ESPM 2053210.

(a) If the fault continues:

(b) If the fault continues:

(2) If the APU Last Leg Report gives the maintenance message:

CONTACTOR 5KA
Fault Code Number: 017

select the A/C batteries ON:

check and repair the aircraft wiring from the ECB (59KD) AC/1 to the START CONTACTOR (5KA) B/3 for a short circuit ASM 494201 ESPM 2052210 ESPM 2053210.

(a) If the fault continues:

Subtask 49-00-00-710-389-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:34:30 UTC