Troubleshooting Guide; Microwave Cooking - Whirlpool MH1150XMQ Tech Sheet

TECH SHEET - DO NOT DISCARD

TROUBLESHOOTING GUIDE

Complete the following steps before
checking microwave circuitry:
1. Check the line voltage, household fuses or
circuit breakers.
2. Check for loose wiring or miswiring within
microwave.
3. Disconnect white wire from power transformer
and discharge high-voltage capacitor.

MICROWAVE COOKING

FUSE
L1
20 AMP
B
CAVITY LIGHT
B
B
SECONDARY
INTERLOCK
SWITCH
R
W
BLOWER FAN TURNS ON AUTOMATICALLY
EXHAUST FAN
L1
FUSE
20 AMP
B
R
BLOWER FAN ON HIGH
L1
FUSE
20 AMP
B
R
B: BLACK
BL: BLUE
BR: BROWN
G: GREEN
GR: GRAY
R: RED
W: WHITE
Y: YELLOW
FOR SERVICE TECHNICIAN'S USE ONLY
MICROCOMPUTER BOARD
FAN ON
RELAY
R
BR
1P2
GR
4P4
TURNTABLE
MOTOR
2.7k-3.8kΩ
BL R
BL
TT 6P4
2
MICROCOMPUTER BOARD
THERMOSTAT
BL
2P3
MICROCOMPUTER BOARD
LOW VOLTAGE
TRANSFORMER
BR
1P2
FAN ON
RELAY
4. All testing must be done with an
ohmmeter having a sensitivity of 20,000
ohms per volt DC or greater, and powered
by at least a 9-volt battery.
5. All operational checks using microwave
energy must be done with the microwave
oven loaded with a minimum of 300 ml
(10 oz.) of water in a microwave-safe
container.
FAN
HIGH/LOW
RELAY
W
3P3
B
4P3
LOW VOLTAGE
TRANSFORMER
G
3P2
CAV LT/DOOR
RELAY
(F/L)
TT
ON/OFF
RELAY
W
1
MICROWAVE
HIGH VOLTAGE
RELAY
SYSTEM
FAN
HIGH/LOW
RELAY
W
3P3
B
4P3
G
3P2
FAN
HIGH/LOW
RELAY
W
3P3
B
4P3
MOTOR
CAPACITOR
R
Y
Y
THERMOSTAT 2
W
R
BL
BL
B
BR
W
PRIMARY
INTERLOCK
SWITCH
W
MONITOR
SWITCH
MAGNETRON
THERMOSTAT
BL
B
MOTOR
CAPACITOR
R
Y
Y
THERMOSTAT 2
W
R
BL BL
B
HOOD FAN
MOTOR
Ω
79-119 (approx.)
BR
MOTOR
CAPACITOR
R
Y
Y
W
R
BL
B
HOOD FAN
MOTOR
Ω
79-119 (approx.)
PART NO. 8184997/4619-651-98301
PAGE 7
CAVITY
W
BL
CAVITY
THERMOSTAT 1
CAVITY
BL
W
CAVITY
THERMOSTAT 1
CAVITY
W
THERMOSTAT 1
BL
BL
W
CAVITY
THERMOSTAT 2
N
N
N