Main Start Contactor output open (APS 3200)

TASK 49-00-00-810-986-A
Main Start Contactor output open (APS 3200)

1. Possible Causes

aircraft wiring
CONTACTOR-MAIN START [5KA]
P/BSW-APU/MASTER SW [14KD]
wiring
ELECTRONIC CONTROL BOX [59KD]
MOTOR-STARTER [8KA]

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
AWM 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
AMM 49-61-34-000-002	Removal of the Electronic Control Box (ECB) (APS 3200)
AMM 49-61-34-400-002	Installation of the Electronic Control Box (ECB) (APS 3200)

3. Fault Confirmation
Subtask 49-00-00-710-394-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 49-00-00-810-351-B ** ON A/C NOT FOR ALL

A. If the APU Last Leg Report gives the maintenance message:

ACFT BAT NOT SELECTED / CONTACTOR (5KA)
Fault Code Number: 085

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 ASM 494201 ESPM 2052210 ESPM 2053210.

(1) If the fault continues:

do a check for a ground signal (with APU MASTER SW pushed) at the MAIN START CONTACTOR (5KA) B/5 ASM 494201.

(a) If there is a ground signal:

replace the CONTACTOR-MAIN START [5KA] AMM 49-42-55-000-001 and AMM 49-42-55-400-001.

1 If the fault continues:

replace the P/BSW-APU/MASTER SW [14KD] .

2 If the fault continues:

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.

(b) If there is no ground signal:

replace the ELECTRONIC CONTROL BOX [59KD] AMM 49-61-34-000-002 and AMM 49-61-34-400-002

1 If the fault continues:

do a check and repair the aircraft wiring between the MAIN START CONTACTOR (5KA) B5 and the terminal block 2266VT/4 AWM 494201 ESPM 2052210 ESPM 2053210.

2 If the fault continues:

replace the MOTOR-STARTER [8KA] AMM 49-42-51-000-007 and AMM 49-42-51-400-007.

Subtask 49-00-00-710-395-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:34:29 UTC