Whirlpool MH1150XMQ User manual

TECH SHEET - DO NOT DISCARD PAGE 1
FOR SERVICE TECHNICIAN'S USE ONLY PART NO. 8184997/4619-651-98301
PRECAUTIONS TO BE OBSERVED BEFORE
AND DURING SERVICING TO AVOID POSSIBLE
EXPOSURE TO EXCESSIVE MICROWAVE ENERGY
a. Do not operate or allow the oven to be
operated with the door open.
b. Make the following safety checks on all
ovens to be serviced before activating the
magnetron or other microwave source, and
make repairs as necessary:
1. Interlock Operation
2. Proper Door Closing
3. Seal and Sealing Surfaces (Arcing,
Wear & Other Damage)
4. Damage to or Loosening of Hinges &
Latches
5. Evidence of Dropping or Abuse
c. Before turning on microwave power for any
service test or inspection within the
microwave generating compartments,
check the magnetron, waveguide or
transmission line and cavity for proper
alignment, integrity and connections.
d. Any defective or misadjusted
components in the interlock, monitor,
door seal, and microwave generation,
and transmission systems shall be
repaired, replaced, or adjusted by
procedures described in service manual
before the oven is released to the owner.
e. A microwave leakage check to verify
compliance with the Federal
performance standard should be
performed on each oven prior to release
to the owner.
f. Do not attempt to operate the oven if the
window area of the door is broken.
Electrical Shock Hazard
Disconnect power before servicing.
Replace all parts and panels before operating.
Failure to do so can result in death or electrical shock.
Display Likely Failure Condition Recommended Repair Procedure
Flashing
colon “:” Power failure After a power failure, the colon “:” will be flashing. Press any key to
end this indication. The colon will then be steady when in stand-by.
-F2- Membrane switch failure Replace membrane switch. If problem persists, replace control board.
-F6- Microwave relay failure Check wiring to relay 4903 for short circuits. If wiring is OK, replace
control board.
FAILURE CODES/INDICATIONS
POWER OUTPUT MEASUREMENT
The power output of the magnetron can be
measured by the following tap water
temperature rise test:
✔Be sure oven cavity is clean and cool (not
used recently).
✔Low voltage will lower the magnetron output.
1. Fill a glass beaker with 1000 ml (32 oz.) of tap
water. Stir the water with a thermometer
(digital recommended) and record the
temperature. This starting temperature should
be between 10°C (50°F) to 24°C (75°F).
2. Place the beaker in the center of the oven.
Operate on HIGH power level for
60 seconds.
3. When done, stir the thermometer through
the water and record the temperature.
4. Subtract the cold water temperature from
the warm water temperature to get the
temperature rise. Normal range is as
shown in the following table:
Voltage
(VAC under load)
Temperature Rise
°C °F
120V 12 - 13 21 - 24
108V 10 - 11 18 - 19

PAGE 2 TECH SHEET - DO NOT DISCARD
PART NO. 8184997/4619-651-98301 FOR SERVICE TECHNICIAN'S USE ONLY
SYMBOL NOTES
CONDITION: DOOR OPENED
H.V.
TRANSFORMER
UP
MAGNETRON
H.V.
CAPACITOR
H.V.
DIODE
FUSE
DOWN
TT
3B
9Y
6BR
7BL
14 OR
15 W
19 BL
16 R
2P5
20 BL
1P5
22 W
NFS
Door
Cav Lt/
Door
4903
W
R
12 B
27 W 25 W
26 W
23 B
INTERLOCK
SECONDARY
ELECTRONIC CONTROL BOARD
INTERLOCK
PRIMARY
INTERLOCK
MONITOR
Motor
FA
F
Turntable
R
Microwave
Relay
Thermostat
Magnetron
HF
CL
LFS
21
MW
2B
40 R
21 R
24 BL
37 R / W
OR/R
OR/R
Capacitor
Y/ W
Exhaust Fan
Thermostat
31 W
34 W
29 G
5P5
4P5
HL
28 BR
30 Y
GND
38 Y/G
L1
P2
L.V.T.
Prim.
Sec.
TR1-5100
N1
1
HL
Night
Light
Hood
Light
L
G
N
G
B
W
120V / 60Hz
Cavity
Thermostat 2
F/L
TTM
13 GR
1
26 W
20 AMP
13 GR
16 R
14 OR
Y
B
BL
Fan
On/Off
8R
10 BL
11 W
HF2 HF1
FT
1P0
5P0
1
P3 P4
Cavity
Thermostat 1
(TCO)
1BL
TT
CAVITY LAMP
TURNTABLE MOTOR
HOOD FAN MOTOR
CL
W
R
HF
Y
B
BL
HOOD LAMP (COOKTOP LAMP)
HL
B: BLACK
BL: BLUE
R: RED
W: WHITE
G: GREEN
Y: YELLOW
P0/P2/P3/P4/P5: CONNECTORS
BR: BROWN
OR: ORANGE
GR: GRAY
1BL
WIRE COLOR - BLUE
WIRE NO. - 1
DWG NO. MU-072
High/Low
Fan
4901
4906
4910
4912
4911
4909
41 R
41 R
SCHEMATIC DIAGRAM

TECH SHEET - DO NOT DISCARD PAGE 3
FOR SERVICE TECHNICIAN'S USE ONLY PART NO. 8184997/4619-651-98301
1
2
3
4
5
1
2
3
4
5
MAGNETRON
HIGH VOLTAGE COMPONENT
YELLOW/ WHITE
H.V.
H.V.
CAPACITOR
DIODE
BLACK
POWER CORD
FUSE & FUSE SADDLE
POWER H.V. TRANSFORMER
ELECTRONIC CONTROL BOARD
CAVITY LAMP &
LAMP HOLDER
THERMOSTAT
MAGNETRON
THERMOSTAT 1
CAVITY
BLACK
WHITE
UPPER INTERLOCK SUPPORT
LOWER INTERLOCK SUPPORT
SWITCH
INTERLOCK
SECONDARY
WHITE BLACK
INTERLOCK
PRIMARY
SWITCH
1
THERMOSTAT
EXHAUST FAN
RED
BLUE
GRAY
ORANGE
WHITE
BLACK
WHITE
MONITOR
INTERLOCK
SWITCH
WHITE
WHITE
BLACK
BLACK
WHITE
HOOD LAMP HOLDER
HOOD LAMP &
WHITE
WHITE
RED
YELLOW/ WHITE
ORANGE/ RED
WHITE
ORANGE/ RED
ORANGE/ RED
WHITE
F
FA
BROWN
GREEN
MOTOR
CAPACITOR
MOTOR
5421
1
2
4
5
RED
WHITE
WHITE
TURNTABLE
SIX POLES
CONNECTOR P5
BLUE
BLUE
RED
4903
12
WHITE
BLACK
WHITE
WHITE
BLACK
WHITE
WHITE
ORANGE
BLUE
BLUE
BROWN
P2
5100
U1
DWG NO. L-M1-075
BLUE
THERMOSTAT 2
CAVITY
1
P4
1
P3
BROWN
BROWN
GRAY
ORANGE
WHITE
BLUE
BLUE BLUE
WHITE
BROWN
BLACK
WHITE
BLUE
BLACK
WHITE
BLUE
YELLOW
RED
YELLOW
RED
GREEN
BROWN
RED
YELLOW
WHITE
ORANGE
GRAY
WHITE
WHITE
BROWN
RED
SIX POLES
CONNECTOR
P0
BROWN
WHITE
WHITE
WHITE
WHITE
BROWN
ORANGE
GRAY
P1
HOOD FAN
MOTOR
ASSEMBLY
RED
PICTORIAL DIAGRAM

PAGE 4 TECH SHEET - DO NOT DISCARD
PART NO. 8184997/4619-651-98301 FOR SERVICE TECHNICIAN'S USE ONLY
WHITE
INTERLOCK
SECONDARY
DWG NO. L-M1-071
ELECTRONIC CONTROL BOARD
1
4903
12
P2
5100
U1
1
P4
1
P3
TURNTABLE
MOTOR
RED
H.V.
TRANSFORMER
TURNTABLE
MOTOR
COOKTOP LAMP
CAVITY LAMP
EXHAUST FAN
THERMOSTAT
WHITE
RED
GREEN
GRAY
BROWN
COOKTOP LAMP
EXHAUST FAN
THERMOSTAT
HOOD FAN
MOTOR
INTERLOCK
PRIMARY
INTERLOCK
SECONDARY
YELLOW
BLUE
WHITE
BLACK
WHITE
ORANGE
P1
PICTORIAL DIAGRAM

TECH SHEET - DO NOT DISCARD PAGE 5
FOR SERVICE TECHNICIAN'S USE ONLY PART NO. 8184997/4619-651-98301
MONITOR
SWITCH
PRIMARY
INTERLOCK
SWITCH
SECONDARY
INTERLOCK
SWITCH
(NC) (NO) (NC)
(NO) (NC) (NO)
LN
DOOR CLOSED
MONITOR
SWITCH
PRIMARY
INTERLOCK
SWITCH
SECONDARY
INTERLOCK
SWITCH
(NC) (NO) (NC)
(NO) (NC) (NO)
LN
DOOR OPEN
Switch Check By Door
Open
Door
Closed
Primary
Interlock
Disconnect the wires at the Primary Interlock Switch.
−+
Check from the common terminal (White/Brown wires) to
the normally open terminal (White wires).
Secondary
Interlock
Disconnect the wires at the Secondary Interlock Switch.
−+
Check from the common terminal (Black wires) to the
normally open terminal (White wire).
Disconnect the wires at the Secondary Interlock Switch.
+−
Check from the common terminal (Black wires) to the
normally closed terminal (Orange wire).
Monitor
Disconnect the wires at the Monitor Switch.
+−
Check from the common terminal (White/Blue wires) to
the normally closed terminal (Red wires).
(+) Continuity (–) No Continuity
NOTE: These diagrams are not intended to show a complete circuit; they represent the position
of switches during “DOOR OPEN” and “DOOR CLOSED” (continuity checks only).
PRIMARY, SECONDARY, AND MONITOR INTERLOCK SWITCH CHECKOUT PROCEDURE
Hood Fan
Motor Assembly
Primary Interlock
Switch
To u c h P a nel
(Membrane Switch)
Monitor Interlock
Switch
Secondary
Interlock Switch
Hood (Cooktop)
Lamp
Cavity Lamp
H.V. Capacitor
Magnetron
H.V. Transformer
H.V. Diode
Line Fuse
Fuse Holder
PCB
(Control Board)
Assembly
Motor Capacitor
Turntable
Motor
Cavity Thermostat 1
Opens at 165°C (329°F)
Closes at -35°C (-31°F)
Exhaust
Opens at 45°C (113°F)
Closes at 60°C (140°F)
Fan Thermostat
Magnetron
Opens at 145°C (293°F)
Closes at 70°C (158°F)
Thermostat
Cavity Thermostat 2
Opens at 125 C
(257 F)
Closes at -35 C (-31 F)
PART S L AYOUT
Not to Scale

PAGE 6 TECH SHEET - DO NOT DISCARD
PART NO. 8184997/4619-651-98301 FOR SERVICE TECHNICIAN'S USE ONLY
Example of use:
When “Cook Time” is
selected, a resistance of
less than 200 ohms will be
observed between 3 and 11
on the flex circuit connector.
See diagram at right.
1
2
3
4
5
6
7
8
910111213
14
60789
15234
TURNTABLE
ADD
MINUTE
COOK
TIME
COOK
POWER
COOK REHEAT DEFROST
POPCORN
BAKED
POTATO
BEVERAGE
FROZEN
ENTREE
TIMER
SET•OFF
LIGHT
ON•NIGHT•OFF
ON•OFF
VENT FAN
HIGH•LOW•OFF
CLOCK
PIN
NO.
ESD GROUND PLANE
WARM
HOLD
CANCEL•OFF
START
PIZZA
14
1
12 34 5 6 78 91011121314
14 PIN FLEX CIRCUIT
CONNECTOR
TOUCH PANEL AND MICROCOMPUTER BOARD TEST
The microwave hood combination is provided
with a self-diagnostic routine that can be
accessed through the touch key pad. To
initiate this routine:
1. Depress the CANCEL•OFF button while
opening the door and while still depressing
the CANCEL•OFF button, unplug the
microwave oven for two seconds and plug it
back in.
2. Release the CANCEL•OFF button and then
close the door.
3. Now, by pressing each button on the
control panel, the number 8 will appear in
the display to indicate that the circuits are
complete and all relays are working.
NOTE: If the CANCEL•OFF button is pressed
during this diagnostic routine, you will exit the
test mode.
Key Name In Circuit Relay Digit*
Popcorn - 1
Baked Potato - 1
Pizza - 3
Beverage - 3
Frozen Entree - 5
Reheat - 5
Cook - 1
Defrost - 3
Cook Time - 1
Cook Power - 3
Add Minute - 5
1 4901 (Cavity Light/Door) 1
2 4911 (Hood Light) 3
3 4903 (MW) 5
4-1
5-3
64906 (Turntable)
4901 (Cavity Light/Door) 5
Key Name In Circuit Relay Digit*
7-1
8 4912 (Night Light) 3
9 4909 (Fan High/Low) 5
Timer
Set•Off -5
0 4910 (Fan On/Off) 3
Clock Buzzer 1
Warm Hold - 5
Start - 1
Turntable
On•Off -3
Light
On•Night•Off -4
Vent Fan
High•Low•Off -2
Cancel•Off - See
Text
* The No. 8 will appear in the display position
indicated in the table.
KEY TABLE FOR TEST MODE
TOUCH PANEL CONTINUITY DIAGRAM

TECH SHEET - DO NOT DISCARD PAGE 7
FOR SERVICE TECHNICIAN'S USE ONLY PART NO. 8184997/4619-651-98301
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.
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.
TROUBLESHOOTING GUIDE
1P2 3P2
FUSE
20 AMP
SECONDARY
INTERLOCK
SWITCH
TURNTABLE
MOTOR
2.7k-3.8kΩ
HIGH VOLTAGE
SYSTEM
MAGNETRON
THERMOSTAT
PRIMARY
INTERLOCK
SWITCH
MONITOR
SWITCH
BL
TT
ON/OFF
RELAY
(F/L)
CAVITY
THERMOSTAT 2
MICROWAVE
MICROCOMPUTER BOARD
CAVITY
THERMOSTAT 1
BL
RELAY
RBR
GR
BL
B
CAVITY LIGHT
GW
W
4P4
CAV LT/DOOR
RELAY
R6P4
21WB
W
L1
B
B
N
TT
R
BR
W
BL
W
3P3
4P3
B
FAN
HIGH/LOW
RELAY
MOTOR
CAPACITOR
B
R
R
Y
Y
BL BL
W
FAN ON
RELAY
LOW VOLTAGE
TRANSFORMER
MICROWAVE COOKING
BL W
EXHAUST FAN
THERMOSTAT
HOOD FAN
MOTOR
79-119 (approx.)Ω
W
CAVITY
CAVITY
THERMOSTAT 1
BL
R
3P3
2P3
MICROCOMPUTER BOARD
L1
B
N
4P3
BB
R
R
Y
Y
BL BL
W
FAN
HIGH/LOW
RELAY
THERMOSTAT 2
MOTOR
CAPACITOR
FUSE
20 AMP
BLOWER FAN TURNS ON AUTOMATICALLY
MICROCOMPUTER BOARD
L1
BR
LOW VOLTAGE
TRANSFORMER
N
BR1P2 3P2
3P3
4P3
WW
HOOD FAN
MOTOR
W
CAVITY
CAVITY
THERMOSTAT 1
BL
BB
R
R
Y
Y
BL
BL
MOTOR
CAPACITOR
W
BR
G
79-119 (approx.)Ω
THERMOSTAT 2
FAN
HIGH/LOW
RELAY
FAN ON
RELAY
FUSE
20 AMP
BLOWER FAN ON HIGH
B:
BL:
BR:
G:
GR:
R:
W:
Y:
BLACK
BLUE
BROWN
GREEN
GRAY
RED
WHITE
YELLOW

PAGE 8 TECH SHEET - DO NOT DISCARD
PART NO. 8184997/4619-651-98301 FOR SERVICE TECHNICIAN'S USE ONLY
MICROCOMPUTER BOARD
L1
BR
LOW VOLTAGE
TRANSFORMER
N
BR1P2 3P2
3P3
4P3
WW
HOOD FAN
MOTOR
W
CAVITY
CAVITY
THERMOSTAT 1
BL
BB
R
R
Y
Y
BL
BL
MOTOR
CAPACITOR
W
BR
G
79-119 (approx.)Ω
THERMOSTAT 2
FAN
HIGH/LOW
RELAY
FAN ON
RELAY
FUSE
20 AMP
BLOWER FAN ON LOW
TRANSFORMER
MICROCOMPUTER BOARD
N
CAVITY
THERMOSTAT 2
CAVITY
THERMOSTAT 1
W
BL
BRBR 1P2 3P2
LOW VOLTAGE
GW
L1
BR
FUSE
20 AMP
MICROWAVE PLUGGED IN - TIME OF DAY DISPLAYED
MICROCOMPUTER BOARD
L1
OVEN CAVITY LIGHT
LOW VOLTAGE
TRANSFORMER
ACTIVATED BY OPENING AND
CLOSING MICROWAVE DOOR
CAV LT/DOOR
RELAY
N
CAVITY
THERMOSTAT 2
CAVITY
THERMOSTAT 1
W
BL
BBR 1P2 3P2
4P4
BB GR
F/L
BR W
RG
FUSE
20 AMP
DOOR OPEN - CAVITY LIGHT IS ON
B:
BL:
BR:
G:
GR:
R:
W:
Y:
BLACK
BLUE
BROWN
GREEN
GRAY
RED
WHITE
YELLOW

TECH SHEET - DO NOT DISCARD PAGE 9
FOR SERVICE TECHNICIAN'S USE ONLY PART NO. 8184997/4619-651-98301
*ALLOWSCURRENT TO FLOW
IN ONE DIRECTION ONLY.
MICROCOMPUTER BOARD
COOKTOP
LIGHT
L1
BR TRANSFORMER BR
N
CAVITY
THERMOSTAT 2
CAVITY
THERMOSTAT 1
BL
BR
FUSE
20 AMP
1P2 3P2
1P3
LOW VOLTAGE
W
W
YW
W
G
DIODE
*
NIGHT
LIGHT ON
RELAY
COOKTOP LIGHT ON LOW (NIGHT LIGHT)
MICROCOMPUTER BOARD
COOKTOP
LIGHT
L1
BR TRANSFORMER BR
N
CAVITY
THERMOSTAT 2
CAVITY
THERMOSTAT 1
BL
BR1P2 3P2
1P3
LOW VOLTAGE
W
W
YW
W
G
HOOD
LIGHT ON
RELAY
FUSE
20 AMP
COOKTOP LIGHT ON HIGH
B:
BL:
BR:
G:
R:
W:
Y:
BLACK
BLUE
BROWN
GREEN
RED
WHITE
YELLOW

PAGE 10 TECH SHEET - DO NOT DISCARD
PART NO. 8184997/4619-651-98301 FOR SERVICE TECHNICIAN'S USE ONLY
COMPONENT TEST RESULTS
H.V.
Transformer
1. Remove wire leads.
2. Measure resistance
(ohmmeter scale: Rx1):
Primary winding -
Secondary winding -
Filament winding -
- Less than 0.5 ohm (approx.)
- 100 ohms (approximate)
-0ohms
3. Measure resistance
(ohmmeter scale: Rx1k):
Primary winding to grounding -
Filament winding to grounding -
- Normal: Infinite
- Normal: Infinite
Magnetron 1. Remove wire leads. Check that
the seal is in good condition.
2. Measure resistance
(ohmmeter scale: Rx1):
Filament terminal - - Normal: Less than 1 ohm
3. Measure resistance
(ohmmeter scale: Rx1k):
Filament to chassis - - Normal: Infinite
H.V. Capacitor 1. Discharge capacitor.
2. Remove wire leads.
3. Measure resistance
(ohmmeter scale: Rx1k):
Terminal to terminal -
Terminal to case -
- Normal: Momentarily
indicates several ohms,
gradually returns to Infinite
- Normal: Infinite
H.V. Diode 1. Measure continuity
(ohmmeter scale: Rx1k):
Forward - - Normal: Continuity
- Abnormal: Infinite
(Some inexpensive
meters may indicate
infinite resistance, both
directions.)
2. Measure continuity
(ohmmeter scale: Rx1k):
Reverse - - Normal: Infinite
- Abnormal: Continuity
CONTINUED ...
Chassis
COMPONENT TESTS
Discharge the high-voltage capacitor and
remove the lead wires from the primary
winding of the high voltage transformer
before conducting any of the following tests.
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.
Conduct a microwave energy test after
performing any tests or repairs to the
microwave.
Check that all wire leads are in the
correct position before operating the
microwave oven.
Grasp wire connectors when removing
the wire leads from microwave parts.