Loss of Phase A of the Windshield Power Supply

TASK 30-42-00-810-802-A
Loss of Phase A of the Windshield Power Supply

1. Possible Causes

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 30-42-00-710-001	Operational Test of the Windshield Anti-Icing and Defogging
ASM 304201
AMM 30-42-34-000-001	Removal of the Window Heat Computer (WHC)
AMM 30-42-34-400-001	Installation of the Window Heat Computer (WHC)

3. Fault Confirmation
Subtask 30-42-00-710-052-A

A. Test
(1) Do the operational test of the windshield anti-icing and defogging AMM 30-42-00-710-001.

4. Fault Isolation
Subtask 30-42-00-865-051-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
123VU	ANTI ICE/L/WHSLD	1DG1	AF10

Subtask 30-42-00-810-051-A

B. If the test gives the maintenance message CHECK WINDSHIELD WHC1 SUPPLY:

(1) If the circuit breaker is closed:

(a) If there is 115VAC:

(b) If there is no 115VAC:

1 If there is no ground signal:
no ground signal:

2 If there is a ground signal:

do a check of the wiring between pin A/A of the WHC 1 (2DG1) and the circuit breaker (1DG1).

a If there is no continuity:

b If there is continuity:

(2) If the circuit breaker is open:

(a) If the fault continues:

(b) If the fault continues:

Subtask 30-42-00-710-053-A

C. Do the operational test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:29:40 UTC