SEE SHEET 3 (BLOCK 6)
Starter Motor Turns the APU Engine but There Is No Combustion (No Increase in EGT)
Figure 113A (Sheet 2)
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. APU WITH THE ELECTRONIC SPEED SWITCH ú
49-00-00
PART NUMBER 3876259 ú
ú 02 Page 162
ú Jul 12/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
L39500
////////////////////////A / GTCP85-129 SERIES /737-300/400/500/ ENGINES /MAINTENANCE MANUAL ////////////////////////
FROM SHEET 2
(BLOCK 5)
YES
NO
6
CONNECT CONNECTOR D1256,
TO THE IGNITION UNIT.
DO A CONTINUITY CHECK AT
THE ELECTRONIC SPEED SWITCH,
S634, CONNECTOR D1245, PINS J
TO M AND PINS E TO L
(WDM 49-31-01). IS THERE AN OPEN CIRCUIT?
YES NO NO
21 WARNING
DO NOT OPERATE THE APU WITH YES
THE LOWER SHROUD REMOVED IF PERSONS ARE IN OR DIRECTLY BELOW THE APU COMPARTMENT. SEE SHEET 4
YOU MUST BE A MINIMUM OF
(BLOCK 8) 3 FEET AWAY FROM THE OUTER EDGE OF THE APU COMPARTMENT OPENING TO OPERATE THE APU WITH THE LOWER SHROUD REMOVED. AN APU TURBINE WHEEL SEPARATION DURING OPERATION CAN CAUSE INJURY TO PERSONS.
EXAMINE THE CIRCUIT FROM THE APU CONTROL UNIT, M280, CONNECTOR D50B, PIN 4 TO THE ELECTRONIC SPEED SWITCH, S634, CONNECTOR D1245, PIN L (WDM 49-31-01).
IS THE CIRCUIT OK?
YES NO
YES NO
23 EXAMINE THE CIRCUITS FROM
THE ELECTRONIC SPEED SWITCH,
S634, CONNECTOR D1245,
PINS M AND K, TO THE
SEQUENCING SWITCH FOR THE OIL
PRESSURE, CONNECTOR D1250,
PINS 4 AND 3 (WDM 49-31-01).
ARE THE CIRCUITS OK?
YES SEE SHEET 4 (BLOCK 24)
Starter Motor Turns the APU Engine but There Is No Combustion (No Increase in EGT)
Figure 113A (Sheet 3)
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. APU WITH THE ELECTRONIC SPEED SWITCH ú
49-00-00
PART NUMBER 3876259 ú
ú 02 Page 163
ú Jul 12/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
L38647
////////////////////////A / GTCP85-129 SERIES /737-300/400/500/ ENGINES /MAINTENANCE MANUAL ////////////////////////
FROM SHEET 3 (BLOCK 7)
YES
NO
8 DISCONNECT CONNECTOR D1245, FROM THE ELECTRONIC
SPEED SWITCH.
MOVE THE APU MASTER SWITCH TO THE "START" POSITION.
AFTER THE AIR INLET DOOR OPENS, DO A CHECK FOR VOLTAGE AT THE ELECTRONIC SPEED SWITCH, S634, CONNECTOR D1245, PIN L (WDM 49-31-01).
IS THERE 28V DC AT PIN L?
YES
NO
9 MOVE THE APU MASTER SWITCH
TO THE "OFF" POSITION.
EXAMINE THE CIRCUITS FROM THE ELECTRONIC SPEED SWITCH, S634, CONNECTOR D1245, PINS M AND K, TO THE SEQUENCING SWITCH FOR THE OIL PRESSURE, CONNECTOR D1250, PINS 4 AND 3 (WDM 49-31-01).
ARE THE CIRCUITS OK?
YES
FROM SHEET 3 (BLOCK 23)
YES
YES24 DO THE APU DRY MOTORING (AMM 49-11-00/201).
DURING THE APU DRY MOTORING, DO A CHECK OF THEOIL PRESSURE.
DID THE OIL PRESSURE INCREASE TO 4.0 PSIG
(27.6 kPa)?
NO NO
25 MOVE THE APU MASTER SWITCH
TO THE "OFF" POSITION.
EXAMINE THE CIRCUIT FROMTHE APU CONTROL UNIT, M280, CONNECTOR D50B, PIN 4 TO THE YES
62 CONNECT CONNECTOR D1245,ELECTRONIC SPEED SWITCH, S634, TO THE ELECTRONIC SPEED
CONNECTOR D1245, PIN L SWITCH.
(WDM 49-31-01).
REPLACE THE APU CONTROL
IS THE CIRCUIT OK?
UNIT, M280 (AMM 49-61-11/401).
YES
26 CONNECT CONNECTOR D1245,
TO THE ELECTRONIC SPEED
SWITCH, S634.
DO THE APU DRY MOTORING (AMM 49-11-00/201).
DURING THE APU DRY MOTORING, DO A CHECK OF THE OIL PRESSURE. NO
DID THE OIL PRESSURE INCREASE TO 4.0 PSIG
(27.6 kPa)?
Starter Motor Turns the APU Engine but There Is No Combustion (No Increase in EGT)
Figure 113A (Sheet 4)
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. APU WITH THE ELECTRONIC SPEED SWITCH ú 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(33)
