Loss of the 601PP and 602PP busbars in Normal Configuration

TASK 24-61-00-810-801-A
Loss of the 601PP and 602PP busbars in Normal Configuration

1. Possible Causes

wiring
C/B-DC SVCE/602PP/SPLY [7PN]
CNTOR-DC SVCE BUS NORM SPLY [8PN]
CNTOR-DC SVCE BUS GND SPLY [3PX]
C/B-ELEC/DC/SVCE/BUS [5PN]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 24-00-00-810-803-A	Circuit Breaker Tripped and/or C/B TRIPPED Warning
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power
ASM 244301
AMM 24-43-55-000-001	Removal of the DC Service Bus Ground Supply Contactor
AMM 24-43-55-400-001	Installation of the DC Service Bus Ground Supply Contactor
ASM 246101
AMM 24-61-55-000-001	Removal of the DC Service Bus Normal Supply Contactor
AMM 24-61-55-400-001	Installation of the DC Service Bus Normal Supply Contactor

3. Fault Confirmation
Subtask 24-61-00-860-050-A

A. Job Set-UP
(1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.

Subtask 24-61-00-710-050-A

B. Test

ACTION	RESULT
1.On the overhead panel 25VU: put the INT LT/DOME switch in the BRT position	the CAPT dome lights do not come on.

4. Fault Isolation
Subtask 24-61-00-865-050-A

A. Table of the circuit breakers used in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
122VU	ELEC/DC/SVCE/BUS	5PN	X24
124VU	DC SVCE/602PP/SPLY	7PN	BD01

Subtask 24-61-00-810-050-A

B. If the test confirms the fault:

Do a check of the status of the circuit breaker (7PN).

(1) If the circuit breaker is closed:

Do a check for 28VDC on the pin F of the contactor (8PN) ASM 246101.

(a) If there is no 28VDC:

Do a check of the wiring between the circuit breaker (7PN) and the contactor (8PN) ASM 246101.

1 If there is no continuity:

Repair the wiring.

2 If there is continuity:

Replace the C/B-DC SVCE/602PP/SPLY [7PN] .

(b) If there is 28VBC:

Do a check for 28VDC on the pin 3 of the contactor (8PN) ASM 246101.

1 If there is 28VDC:

Replace the CNTOR-DC SVCE BUS NORM SPLY [8PN] AMM 24-61-55-000-001 and AMM 24-61-55-400-001.

a If the fault continues:

Do a check and repair the wiring between A/E of the contactor (8PN) and the busbars 601PP and 602PP ASM 244301.

2 If there is no 28VDC:

Do a check of the wiring between the circuit breaker (5PN) and the pin 3 of the contactor (8PN) ASM 246101.

a If there is no continuity:

Repair the wiring.

b If there is continuity:

Replace the CNTOR-DC SVCE BUS GND SPLY [3PX] AMM 24-43-55-000-001 and AMM 24-43-55-400-001.

c If the fault continues:

Replace the C/B-ELEC/DC/SVCE/BUS [5PN] .

(2) If the circuit breaker is open:

Do the procedure (Ref. TSM TASK 24-00-00-810-803).

(a) If the fault continues:

Replace the C/B-DC SVCE/602PP/SPLY [7PN] .

Subtask 24-61-00-710-051-A

C. Do the test given in Para. 3 and make sure that the CAPT dome lights come on.

5. Close-up
Subtask 24-61-00-860-051-A

A. Put the aircraft back to its initial configuration.
(1) On the overhead panel 25VU, put the INT LT/DOME switch in the OFF position.
(2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:26:59 UTC