Recording on All the Channels Inoperative

TASK 23-71-00-810-805-A
Recording on All the Channels Inoperative

1. Possible Causes

CVR [1RK]
wiring
C/B-COM/CVR/SPLY [2RK]
C/B-COM/CVR/CTL [4RK]
C/B [23RK]
C/B [26RK]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 23-71-00-710-001	Operational Test of the CVR and the CVR Channel Recording
ASM 237101
AMM 23-71-35-000-001	Removal of the Cockpit Voice Recorder (CVR) 1RK
AMM 23-71-35-400-001	Installation of the Cockpit Voice Recorder (CVR) 1RK

3. Fault Confirmation
Subtask 23-71-00-710-058-A

A. Test
(1) Do the operational test of the CVR and the CVR channel recording AMM 23-71-00-710-001.

4. Fault Isolation
Subtask 23-71-00-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	COM/CVR/SPLY	2RK	E14
** ON A/C NOT FOR ALL
49VU	COM/CVR/SPLY	23RK	E14
49VU	COM/CVR/CTL	26RK	E13

Subtask 23-71-00-810-054-A ** ON A/C NOT FOR ALL

B. If during the operational test the recording is inoperative:

push the MON. IND. FOR GND/CTL pushbutton switch (11TU) on the panel 21VU.

(1) If it comes on and the fault continues:

replace CVR [1RK] AMM 23-71-35-000-001 and AMM 23-71-35-400-001.

(a) If the fault continues:

do a check of the circuit breaker (2RK) status.

1 If the circuit breaker is closed:

do a check for a ground signal at pin 3 of the CVR (1RK) ASM 237101.

a If there is no ground signal:

repair the wiring from CVR (1RK) pin A/3 to the first terminal block ASM 237101.

b If there is a ground signal:

do a check of the wiring from the C/B (2RK) to the first terminal block and of the relay (8RK) ASM 237101.
. If there is no continuity:
* repair the above wiring.
. If there is continuity:
* replace the C/B-COM/CVR/SPLY [2RK] .

2 If the circuit breaker is open:

close it.

a If it opens again:

replace the C/B-COM/CVR/SPLY [2RK] .

b If it opens again:

do a check for a short to ground and repair the wiring of the system ASM 237101.

(2) If it does not come on:

do a check of the circuit breaker (4RK) status.

(a) If the circuit breaker is closed:

do a check of the wiring located downstream of the circuit breaker (4RK) ASM 237101.

1 If there is no continuity:

repair the above wiring.

2 If there is continuity:

replace the C/B-COM/CVR/CTL [4RK] .

(b) If the circuit breaker is open:

close it.

1 If it opens again:

replace the C/B-COM/CVR/CTL [4RK] .

2 If it opens again:

do a check for a short to ground and repair the wiring located downstream of the circuit breaker (4RK) ASM 237101.

Subtask 23-71-00-810-054-B ** ON A/C NOT FOR ALL