Failure of the Cockpit Call

TASK 23-42-00-810-806-A
Failure of the Cockpit Call

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 23-42-00-710-001	Operational Test of the Mechanic Call
ASM 234201

3. Fault Confirmation
Subtask 23-42-00-710-060-A

A. Test
(1) Do the operational test of the mechanic call AMM 23-42-00-710-001.

4. Fault Isolation
Subtask 23-42-00-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	EIS/HORN/SPLY	2WC	P09

Subtask 23-42-00-810-056-A

B. If during the operational test the indicator light and the horn of the cockpit call do not operate:

(1) If the circuit breaker is closed:

do a check for a ground signal at pins 4 and 8 of the CALLS/MECH pushbutton switch (1WC) ASM 234201.

(a) If there is no ground signal:

repair the wiring between CALLS/MECH pushbutton switch (1WC) pins 4 and 8 and the ground terminal ASM 234201.

(b) If there is a ground signal:

do a check of the wiring between the circuit breaker (2WC) and the first terminal block ASM 234201.

1 If there is no continuity:

2 If there is continuity:

(2) If the circuit breaker is open:

(a) If it opens again:

(b) If it opens again:

do a check for a short to ground and repair the wiring of the system ASM 234201.

Subtask 23-42-00-710-061-A

C. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:25:42 UTC