ARE THE RESISTANCES 0-1 OHMS (MAXIMUM)? YES
NO
22 MEASURE THE RESISTANCE AT THE ELECTRONIC SPEED SWITCH, S634, CONNECTOR D1245, FROM PIN G TO PIN H (WDM 49-31-01).
IS THE RESISTANCE 4000-6000 OHMS? YES
NO
23 MEASURE THE RESISTANCE AT THE ELECTRONIC SPEED SWITCH, S634, CONNECTOR D1245, FROM PINS A TO G, M TO F, L TO E B TO G (WDM 49-31-01).
ARE THE RESISTANCES A MINIMUM OF 1000K OHMS?
YES NO
24 MEASURE THE RESISTANCE AT THE SEQUENCING PRESSURE SWITCH FOR THE OIL, CONNECTOR D1250, FROM PIN 3 TO PIN 4 (WDM 49-31-01).
IS THE RESISTANCE MORE THAN 1000K OHMS?
YES SEE SHEET 3 (BLOCK 25)
APU Engine Speed Decreases
Figure 125 (Sheet 2)
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. APU WITH THE ELECTRONIC SPEED SWITCH ú
49-00-00
PART NUMBER 305593 ú
ú 02 Page 180Y
ú Jul 12/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A13117
////////////////////////A / GTCP85-129 SERIES /737-300/400/500/ ENGINES /MAINTENANCE MANUAL ////////////////////////
FROM SHEET 2 (BLOCK 24)
YES
NO
25 MEASURE THE RESISTANCE AT
THE FUEL SOLENOID VALVE, CON-
NECTOR D1264, FROM PIN A TO
PIN B (WDM 49-31-01).
ARE THE RESISTANCES 20-45 OHMS?
YES
NO
26 DO A CHECK FOR THE INTER-
MITTENT ELECTRICAL SIGNAL AT
THE ELECTRONIC SPEED SWITCH
(110% SWITCH), S634, CONNECTOR
D1245, PIN E (WDM 49-31-01).
IS THE ELECTRICAL SIGNAL TO PIN E CONTINUOUS AND STRONG?
YES
NO
27 DO A CHECK FOR THE INTER-
MITTENT ELECTRICAL SIGNAL AT
THE SEQUENCING PRESSURE SWITCH
FOR THE OIL, CONNECTOR D1250,
PIN 3 (WDM 49-31-01).
IS THE ELECTRICAL SIGNAL TO PIN 3 CONTINUOUS AND STRONG?
YES
NO
28 DO A CHECK FOR THE INTER-MITTENT ELECTRICAL SIGNAL AT
THE FUEL SOLENOID VALVE, CON-
NECTOR D1264, PIN A
(WDM 49-31-01).
IS THE ELECTRICAL SIGNAL TO PIN A CONTINUOUS AND STRONG?
62 REPLACE THE CAUSE OF THE INTERMITTENT ELECTRICAL SIGNAL.
APU Engine Speed Decreases
Figure 125 (Sheet 3)
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. APU WITH THE ELECTRONIC SPEED SWITCH ú
49-00-00
PART NUMBER 305593 ú
ú 02 Page 180Z
ú Jul 12/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
E06309
PREREQUISITES
MAKE SURE THE AIRPLANE IS IN THIS CONFIGURATION: ELECTRICAL POWER IS ON (AMM 24-22-00/201)
APU ENGINE SPEED DECREASES
POSSIBLE CAUSES:
1.
INLET DOOR SWITCH, S284, PROBLEM OR ADJUSTMENT (AMM 49-15-00/501)
2.
INTERMITTENT ELECTRICAL SIGNAL TO THESE COMPONENTS: . FUEL SOLENOID VALVE (AMM 49-31-31/401) . SEQUENCING SWITCH FOR THE OIL PRESSURE (AMM 49-61-41/401) . ELECTRONIC SPEED SWITCH, S634, (AMM 49-61-22/401).
3.
APU CONTROL UNIT, M280, PROBLEM (AMM 49-61-11/401).
FAULT ISOLATION:
NO
1 DO A CHECK OF THE
ADJUSTMENT OF THE INLET DOOR
SWITCH, S284
(AMM 49-15-00/501).
IS THE INLET DOOR SWITCH ADJUSTED CORRECTLY?
YES
YES
2 REMOVE THE INLET DOOR
SWITCH, S284, CONNECTOR D1246.
IS THERE DAMAGE TO THE
CONNECTOR?
NO
NO
YES
NO
4 EXAMINE THE CIRCUIT FROM
THE INLET DOOR SWITCH, S284,
CONNECTOR D1246, PIN 4, TO THE
APU CONTROL UNIT, M280,
CONNECTOR D50B, PIN 46
(WDM 49-31-01).
IS THE CIRCUIT OK?
YES SEE SHEET 2
(BLOCK 21)
52 REPAIR THE DAMAGE THAT YOUFIND.
IF NECESSARY, REPLACE THE INLET DOOR SWITCH, S284.
APU Engine Speed Decreases
Figure 125A (Sheet 1)
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. APU WITH THE ELECTRONIC SPEED SWITCH ú
49-00-00
PART NUMBER 3876259 ú
ú 02 Page 181
ú Jul 12/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737-300 400 500 AMM 飞机维护手册 AIRBORNE AUXILIARY POWER 1(47)
