PMOR3021S
PMOR3021B
PMOR3021R
SERVICE MANUAL
Rev 1
S94M245P3021S
OVER THE RANGE
MICROWAVE OVEN
MODELS
PMOR3021S
PMOR3021B
PMOR3021R
In the interest of user-safety the oven should be restored to its original condition and only parts identical to those specified should
be used.
WARNING TO SERVICE PERSONNEL: Microwave ovens contain circuitry capable of producing very high voltage
and current. Contact with the following parts may result in a severe, possibly fatal, electrical shock. (Inverter unit
that includes High Voltage Capacitor, High Voltage Power Transformer, High Voltage Rectifier and Heat sink etc.,
and Magnetron, High Voltage Harness etc..)
TABLE OF CONTENTS
Page
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO
AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY ................. INSIDE FRONT COVER
BEFORE SERVICING .................................................................................................... INSIDE FRONT COVER
WARNING TO SERVICE PERSONNEL .............................................................................................................. 1
MICROWAVE MEASUREMENT PROCEDURE .................................................................................................. 2
FOREWORD AND WARNING ............................................................................................................................. 3
PRODUCT SPECIFICATIONS ............................................................................................................................ 4
GENERAL INFORMATION ................................................................................................................................. 5
OPERATION ........................................................................................................................................................ 7
TROUBLESHOOTING GUIDE .......................................................................................................................... 11
TEST PROCEDURE .......................................................................................................................................... 13
TOUCH CONTROL PANEL ASSEMBLY ........................................................................................................... 23
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE .............................................................. 30
PICTORIAL DIAGRAM ...................................................................................................................................... 39
POWER UNIT CIRCUIT .................................................................................................................................... 40
LSI UNIT CIRCUIT ............................................................................................................................................. 41
PRINTED WIRING BOARD ............................................................................................................................... 42
PARTS LIST ...................................................................................................................................................... 43
PACKING AND ACCESSORIES ....................................................................................................................... 48
dis tinctive appliances
This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
1
PMOR3021S
PMOR3021B
PMOR3021R
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, and other damage), (4) damage to or loosening of hinges and 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, wave guide 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 this 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.
BEFORE SERVICING
Before servicing an operative unit, perform a microwave emission check as per the Microwave
Measurement Procedure outlined in this service manual.
If microwave emissions level is in excess of the specified limit, contact DACOR immediately @
1-800-793-0093.
If the unit operates with the door open, service person should 1) tell the user not to operate the oven and
2) contact DACOR and Food and Drug Administration's Center for Devices and Radiological Health
immediately.
Service personnel should inform DACOR of any certified unit found with emissions in excess of 4mW/cm2.
The owner of the unit should be instructed not to use the unit until the oven has been brought into
compliance.
DANGER CAUTION
HIGH VOLTAGE
Do not energize a microwave oven with the outer case cabinet removed, because a microwave oven
generates High Voltage in the circuit.
If you intend to operate the oven employing the high frequency switching power converter circuit, you should
take special precautions to avoid an electrical shock hazard.
The high voltage transformer, high voltage capacitor and high voltage diode have energized high voltage
potential approx. 8 KV.
The aluminium heat sink is connected to the switching power transistor Collector pole, and has an energized
high voltage potential approx. 650V peak.
DO NOT ACCESS THE HIGH VOLTAGE TRANSFORMER, HIGH VOLTAGE CAPACITOR, HIGH VOLTAGE DIODE AND HEAT SINK WHEN THE POWER SUPPLY IS CONNECTED TO AN ELECTRICAL
OUTLET.
2
PMOR3021S
PMOR3021B
PMOR3021R
WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of producing very high voltage and current, contact with
following parts may result in a severe, possibly
fatal, electrical shock.
(Example)
Inverter unit that includes High Voltage Capacitor,
High Voltage Power Transformer, High Voltage
Rectifier, Heat sink etc., and Magnetron, High
Voltage Harness etc..
Read the Service Manual carefully and follow all
instructions.
Don't Touch !
Danger High Voltage
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. Reconnect the leads to the primary of the inverter unit.
5. Reinstall the outer case (cabinet).
6. Reconnect the power supply cord after the outer case is
installed.
7. Run the oven and check all functions.
Before Servicing
1. Disconnect the power supply cord
, and then
remove outer case.
2. Open the door and block it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
WARNING:RISK OF ELECTRIC SHOCK.
DISCHARGE THE HIGH-VOLTAGE
CAPACITOR BEFORE SERVICING.
After repairing
The high-voltage capacitor remains charged about 60
seconds after the oven has been switched off. Wait for 60
seconds and then short-circuit the connection of the highvoltage capacitor (that is the connecting lead of the highvoltage rectifier) against the chassis with the use of an
insulated screwdriver.
1. Reconnect all leads removed from components during
testing.
2. Reinstall the outer case (cabinet).
3. Reconnect the power supply cord after the outer case is
installed.
4. Run the oven and check all functions.
Whenever troubleshooting is performed the power supply
must be disconnected. It may in, some cases, be necessary
to connect the power supply after the outer case has been
removed, in this event,
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. Disconnect the leads to the primary of the inverter unit.
5. Ensure that these leads remain isolated from other
components and oven chassis by using insulation tape.
6. After that procedure, reconnect the power supply cord.
Microwave ovens should not be run empty. To test for the
presence of microwave energy within a cavity, place a cup
of cold water on the oven turntable, close the door and set
the power to HIGH and set the microwave timer for two (2)
minutes. When the two minutes has elapsed (timer at zero)
carefully check that the water is now hot. If the water
remains cold carry out Before Servicing procedure and reexamine the connections to the component being tested.
When all service work is completed and the oven is fully
assembled, the microwave power output should be checked
and microwave leakage test should be carried out.
When the testing is completed,
1
PMOR3021S
PMOR3021B
PMOR3021R
SERVICING FOR INVERTER UNIT
WARNING
This inverter unit contains circuitry capable of producing high voltage and high current. Contact with any part
of the high voltage will result in electrocution.
DO NOT ACCESS ANY PARTS OF INVERTER UNIT WITH POWER SUPPLY CONNECTED.
DO NOT OPERATE INVERTER UNIT ITSELF.
It is dangerous because this unit contains high voltage components.
MICROWAVE MEASUREMENT PROCEDURE
A. Requirements:
1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven
should not exceed 1mW/cm2 at any point 5cm or more from the external surface of the oven, measured prior to acquisition
by a purchaser, and thereafter (through the useful life of the oven), 5 mW/cm2 at any point 5cm or more from the external
surface of the oven.
2) Safety interlock switches: Primary interlock switch shall prevent microwave radiation emission in excess of the
requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission in excess of
5 mW/cm2 at any point 5cm or more from the external surface of the oven.
B. Preparation for testing:
Before beginning the actual measurement of leakage, proceed as follows:
1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.
Important:
Survey instruments that comply with the requirement for instrumentation as prescribed by the performance standard
for microwave ovens, 21 CFR 1030.10(c)(3)(i), must be used for testing.
2) Place the oven tray in the oven cavity.
o
o
3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20 ±5C (68 F) in the center of the oven cavity.
The water container shall be a low form of 600 ml (20 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.)
and made of an electrically nonconductive material such as glass or plastic.
The placing of this standard load in the oven is important not only to protect the oven, but also to insure that any leakage
is measured accurately.
4) Set the cooking control on Full Power Cooking Mode
5) Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed,
replace it with 275 ml of cool water.
C. Leakage test:
Closed-door leakage test (microwave measurement)
1) Grasp the probe of the survey instrument and hold it perpendicular to the gap between the door and the body of the oven.
2) Move the probe slowly, not faster than 1 in./sec. (2.5 cm/sec.) along the gap, watching for the maximum indication on
the meter.
3) Check for leakage at the door screen, sheet metal seams and other accessible positions where the continuity of the metal
has been breached (eg., around the switches, indicator, and vents).
While testing for leakage around the door pull the door away from the front of the oven as far as is permitted by the closed
latch assembly.
4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2,
and that the primary interlock switch and secondary interlock switch do turn the oven OFF before any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report.
2
PMOR3021S
PMOR3021B
PMOR3021R
SERVICE MANUAL
dis tinctive appliances
PRODUCT DESCRIPTION
MICROWAVE OVENS
PMOR3021S/PMOR3021B/PMOR3021R
GENERAL INFORMATION
FOREWORD
This Manual has been prepared to provide Dacor Service Personnel
with Operation and Service Information for the DACOR MICROWAVE OVENS, PMOR3021S, PMOR3021B and PMOR3021R.
OPERATION
It is recommended that service personnel carefully study the entire
text of this manual so that they will be qualified to render satisfactory
customer service.
TROUBLESHOOTING GUIDE AND
TEST PROCEDURE
Check the interlock switches and the door seal carefully. Special
attention should be given to avoid electrical shock and microwave
radiation hazard.
TOUCH CONTROL PANEL
WARNING
Never operate the oven until the following points are ensured.
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is no other visible damage with the oven.
COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
WIRING DIAGRAM
Servicing and repair work must be carried out only by trained service
personnel.
DANGER
Certain initial parts are intentionally not grounded and
present a risk of electrical shock only during servicing.
Service personnel - Do not contact the following parts while
the appliance is energized;
Inverter unit that includes High Voltage Capacitor, High
Voltage Power Transformer, High Voltage Rectifier, Heat
sink, etc., and Magnetron, High Voltage Harness etc.;
If provided, Vent Hood, Fan assembly, Cooling Fan Motor.
All the parts marked “*” on parts list are used at voltages more than
250V.
Removal of the outer wrapper gives access to voltage above 250V.
All the parts marked “∆” on parts list may cause undue microwave
exposure, by themselves, or when they are damaged, loosened
or removed.
distinctive appliances
1440 Bridge Gate Dr.
Diamond Bar, CA 91765
3
PARTS LIST
PMOR3021S
PMOR3021B
PMOR3021R
PRODUCT SPECIFICATION
ITEM
DESCRIPTION
Power Requirements
120 Volts / 12 Amperes
60 Hertz
Single phase, 3 wire grounded
Power Output
1200 watts (IEC TEST PROCEDURE)
Operating frequency of 2450MHz
Case Dimensions
Width 29-15/16"
Height 17"
Depth 15- 9/16"
Cooking Cavity Dimensions
2.1 Cubic Feet
Width 22-9/16"
Height 10-9/16"
Depth 15"
Hood lamp
2 bulbs, 20W x 2, Incandescent light bulbs
Hood fan
Approx. 300 C.F.M./ 270 C.F.M.
Control Complement
Touch Control System
Clock ( 1:00 - 12:59 )
Timer (0 - 99 min. 99 seconds)
Microwave Power for Variable Cooking
Repetition Rate;
P-HI ................................................. Full power throughout the cooking time
P-90 .................................................................... approx. 90% of Full Power
P-80 .................................................................... approx. 80% of Full Power
P-70 .................................................................... approx. 70% of Full Power
P-60 .................................................................... approx. 60% of Full Power
P-50 .................................................................... approx. 50% of Full Power
P-40 .................................................................... approx. 40% of Full Power
P-30 .................................................................... approx. 30% of Full Power
P-20 .................................................................... approx. 20% of Full Power
P-10 .................................................................... approx. 10% of Full Power
P-0 .................................................... No power throughout the cooking time
SENSOR CENTER pads, MEAL TIME pads
HELP GUIDE pad, KEEP WARM PLUS pad, EASY DEFROST pad
SHORT CUTS pads, Numer selection pads, POWER LEVEL pad
Timer/Clock pad, Stop/Clear pad, START/EAST MINUTE pad
FAN: HI/LO, LIGHT: HI/LO
Oven Cavity Light
20W x 1 Incandescent light bulb
Safety Standard
UL Listed
FCC Authorized
DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J
Canadian Standards Association
Health CANADA, Industry Canada
Weight
Approx. 44 lbs.
4
PMOR3021S
PMOR3021B
PMOR3021R
GENERAL INFORMATION
GROUNDING INSTRUCTIONS
This oven is equipped with a three prong grounding plug. It must be plugged into a wall receptacle that is properly installed
and grounded in accordance with the National Electrical Code and local codes and ordinances.
In the event of an electrical short circuit, grounding reduces the risk of electric shock by providing an escape wire for the
electric current.
WARNING:
Improper use of the grounding plug can result in a risk of electric shock.
Electrical Requirements
The oven is equipped with a 3-prong grounding plug. DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE THE
GROUNDING PIN FROM THE PLUG.
The power supply cord and plug must be connected to a separate 120 Volt AC, 60 Hz, 15 Amp. or more dedicated line, using
a grounded receptacle. The receptacle should be located inside the cabinet directly above the Microwave Oven/Hood system
mounting location.
Grounded
Receptacle Box
3-Pronged Plug
Grounding Pin
3-Pronged Receptacle
OVEN DIAGRAM
8
11
8
1
7
3
2
6
8
4
5
1. Oven door with see-through window.
2. Door hinges.
3. Oven lamp.
It will light when oven is operating or door is open.
4. Door latches.
The oven will not operate unless the door is securely closed.
5. One touch door open button
6. Auto-Touch control panel.
7. Timer display: Digital display, 99 minutes 00 seconds.
8. Ventilation openings.
9. Light Cover.
10. Grease filters.
11. Power supply cord
5
10
9
10
PMOR3021S
PMOR3021B
PMOR3021R
PMOR3021S
NOTE:
Some one-touch cooking features such as "MINUTE PLUS" are disabled after three minutes when the oven
is not in use. These features are automatically enabled when the door is opened and closed or the STOP/
CLEAR pad is pressed.
6
PMOR3021S
PMOR3021B
PMOR3021R
OPERATION
DESCRIPTION OF OPERATING SEQUENCE
The following is a description of component functions during
oven operation.
(1) When the door opens from a closed position, the
primary interlock switch and secondary interlock
switch open their contacts, and then the monitor
switch contacts close. And contacts of the relay
(RY1) remain closed.
(2) When the door is closed from the open position, the
monitor switch contacts first open and the stop
switch contacts open, and then the contacts of the
secondary interlock switch and primary interlock
switch close. And contacts of the relay (RY1) open.
If the secondary interlock switch and primary interlock
switch fail with their contacts closed when the door is
opened, the closing of the monitor switch contacts will form
a short circuit through the monitor fuse, secondary interlock
switch, primary interlock switch and relay (RY1) causing the
monitor fuse to blow.
OFF CONDITION
Closing the door activates the stop switch, primary interlock
switch and secondary interlock switch. (In this condition, the
monitor switch contacts are opened.)
When oven is plugged in, 120 volts A.C. is supplied to the
control unit. (Figure O-1).
1. The display will show flashing "88 : 88".
To set any program or set the clock, you must first
touch the STOP/CLEAR button. The display will clear,
and " : " will appear .
COOKING CONDITION
Program desired cooking time touching the NUMBER pads.
When the START button is touched, the following operations occur:
VARIABLE COOKING
When Variable Cooking Power is programmed, the 120
volts A.C. is supplied to the inverter unit which is operated
by the control unit. Microwave power operation is as follows:
The oven can be set for any of 11 power levels: 0% to
100%(HIGH). The variable cooking power less than 40% is
programmed at the ratio of ON time and OFF time within 32
sec./ cycle time base.
1. The contacts of relays are closed and components
connected to the relays are turned on as follows.
(For details, refer to Figure O-2)
RELAY
RY1
RY3, RY4
CONNECTED COMPONENTS
Oven lamp / Fan motor / Stirrer motor
Hood fan motor
CONNECTION BETWEEN POWER SETTING AND ON/
OFF TIME OF INVERTER UNIT.
2. 120 volts A.C. is supplied to the inverter unit and is
converted in order to power of the magnetron by the high
frequency switching power circuit. The frequency is
approx. 33 _ 45 KHz.
3. The filament winding voltage of H.V. transformer heats
the magnetron filament and the H.V. winding gives a high
voltage approx. 2 KV to activaite a voltage doubler
circuit. Then approx. 4KV peak voltage power is supplied
to the magnetron cathode terminal.
4. The microwave energy produced by the magnetron is
channelled through the waveguide into the cavity feedbox, and then into the cavity where the food is placed to
be cooked.
5. Upon completion of the cooking time, the inverter unit,
oven lamp, etc. are turned off, and the generation of
microwave energy is stopped. The oven will revert to the
OFF condition.
6. When the door is opened during a cook cycle, the monitor
switch, stop switch, secondary interlock switch and primary
interlock switch are activated with the following results.
The circuits to the stirrer motor, the cooling fan motor, the
turntable motor, and the inverter unit are de-energized,
and the touch screen displays the time still remaining in
the cook cycle when the door was opened.
7. The monitor switch is electrically monitoring the operation
of the secondary interlock switch and primary interlock
switch and is mechanically associated with the door so
that it will function in the following sequence.
OUTPUT POWER SETTING ON TIME
OFF TIME
Power 100%
Power 90%
Power 80%
Power 70%
Continue operation
Power 60%
Power 50%
Power 40%
26 sec.
6 sec.
Power 30%
22 sec.
10 sec.
Power 20%
16 sec.
16 sec.
Power 10%
8 sec.
24 sec.
Power 0%
0 sec.
32 sec.
Note: The ON/OFF time ratio does not correspond with
the percentage of microwave power, because
approx. 3 seconds are needed for heating of the
magnetron filament.
SENSOR COOKING CONDITION
Using the Sensor cooking function the food is cooked without
figuring time, power level or quantity. When the oven senses
enough steam from the food, it relays the information to its
microprocessor which will calculate the remaining cooking
time and power level needed for best results. When the food
is cooked, water vapor is developed. The sensor “senses”
the vapor and its resistance increases gradually. When the
7
PMOR3021S
PMOR3021B
PMOR3021R
VENTILATION METHODS HOT AIR EXHAUST
resistance reaches the value set according to the menu,
supplementary cooking is started. The time of supplementary cooking is determined by experiment with each food
category and input into the LSI.
An example of how sensor works: (BAKED POTATOES)
1. VERTICAL VENTING
For this venting method, hot air rising from the
conventional range below is drawn in by the hood fan
motor through the grease filters at the right and left sides
of the base cover, up through the right and left sides of
the oven cavity, then discharged vertically at rear center
top of the oven, into the customer's vent system.
: AIR FLOW
OW
TO DUCT
TO DUCT
1. Potatoes at room temperature. Vapor is emitted very
MIC
slowly.
R
HOOD FAN MOTOR
AVE
HOOD
INTAKE
DUCT R
GREASE
FILTER
2. Heat Potatoes. Moisture and humidity is emitted rapidly.
You can smell the aroma as it cooks.
AH SENSOR
MIC
RO
2. HORIZONTAL VENTING
The air handing is the same as VERTICAL VENTING
except that the final air discharge is directed horizontally
out from the top rear of the oven into the customer's vent
system.
: AIR FLOW
WA
VE
HOOD FAN MOTOR
3. Sensor detects moisture and humidity and calculates
cooking time and variable power.
TO DUCT
HOOD
INTAKE
DUCT R
Cooking Sequence.
1. Operate the oven in sensor cooking mode by referring to
the operation manual.
NOTE: The oven should not be operated on SENSOR
immediately after plugging in the unit. Wait two
minutes before cooking on SENSOR.
2. The coil of shut-off relay (RY-1) is energized, the turntable
motor, oven lamp and cooling fan motor are turned on,
but the inverter unit is not turned on.
3. After about 32 seconds, the cook relay (RY-2) is
energized. The power transformer is turned on,
microwave energy is produced and first stage is started.
The 32 seconds is the cooling time required to remove
any vapor from the oven cavity and sensor.
NOTE: During this first stage, do not open the door or touch
STOP/CLEAR pad.
4. When the sensor detects the vapor emitted from the
food, the display switches over to the remaining cooking
time and the timer counts down to zero.
At this time, the door may be opened to stir, turn, or
season food.
5. When the timer reaches zero, an audible signal sounds.
The shut-off relay is de-energized and the inverter unit,
oven lamp, etc. are turned off.
6. Opening the door or touching the STOP/CLEAR pad, the
time of day will reappear on the display and the oven will
revert to an OFF condition.
GREASE
FILTER
3. RE-CIRCULATION (INSIDE VENTING)
The air handing is the same as VERTICAL VENTING
except that the final air discharge is directed horizontally
through the upper front of the oven into the kitchen. In
this case, the accessory charcoal filter RK-260 must be
provided to filter the air before it leaves the oven.
: AIR FLOW
HOOD FAN MOTOR
HOOD EXHAUST
LOUVER
HOOD
INTAKE
DUCT R
GREASE
FILTER
8
CHARCOAL
FILTER
PMOR3021S
PMOR3021B
PMOR3021R
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. CLOCK APPEARS ON DISPLAY
YLW B1
RY5
C3
C5
C2
B3
Low
RY6
BLK
WHT
WHT
WHT
A1
H3
OVEN
LAMP
RELAY
A3
RED
HOOD
CAPACITOR
F2
NOISE FILTER
COM
F1
A3
BRN or PPL
WHT
GRY
GRY
BLU
BLU
BLU
WHT
BLU
M
INVERTER
UNIT
BLU
GRY
BLU
YLW
RED
YLW
RED
AC3
N.C.
BLU
HL
BLU
RED
MONITOR
SWITCH
HUMIDITY
SENSOR
WHT
HOOD
LAMP
HL
GRY
BLU
COM.
N. O.
A7
A9
YLW or ORG
A1
HOOD
MOTOR
FA
F
F3
RY1
C4
BLU
RED
BRN
BRN
BRN
WHT
H1
NC
RY3
High
WHT
C1
BLK
BLK
L
E1
BLK
BLU
GND
STOP
SWITCH
RY4
HOOD FAN
THERMAL
CUT OUT
N
STIRRER
MOTOR
E2
MAGNETRON
RED
RED
WHT
WHT
GRN
LVT
RED
GRN
COM N.O.
FAN
MOTOR
WITH
TEMP. FUSE
C3
RED A5
120VAC
60Hz.
WHT
OVEN
LAMP
ORG
BLK
RED
RED
CONTROL UNIT
H
COM
N.O.
PRIMARY
INTERLOCK
SWITCH
RED
RED
ORG
RED
OVEN THERMAL
CUT OUT
RED
BRN
BLK
RED
ORG
FUSE
20A
SECONDARY
INTERLOCK
SWITCH
RED
RED
BLK
BLK
NOTES:
1. Circuits / Wire Colors subject to change without notice.
2. Terminal that located to the right side on the lamp socket's back view
must be connected to neutral wire.
3. Only certain models use the absolute humidity sensor
Figure O-1. Oven Schematic-Off Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. COOKING TIME PROGRAMMED
3. VARIABLE COOKING CONTROL "HIGH"
4. "START" PAD TOUCHED
C2
RED
RED
WHT
WHT
BLK
BRN
BRN
BRN
E1
BLK
RY5
C5
B3
H1
NC
RY3
High
Low
RY6
WHT
F3
COM
F1
N. O.
COM.
WHT
BLU
M
INVERTER
UNIT
GRY
BLU
WHT
BLU
BLU
BLU
AC3
N.C.
WHT
HL
RED
MONITOR
SWITCH
HUMIDITY
SENSOR
GRY
GRY
HOOD
LAMP
BLU
RED
A7
YLW or ORG
BRN or PPL
YLW
RED
A9
BLU
BLU
A3
HL
GRY
BLU
FA
F
F2
NOISE FILTER
A1
A3
RED
RY1
HOOD
MOTOR
A1
H3
OVEN
LAMP
RELAY
HOOD
CAPACITOR
YLW
WHT
STOP
SWITCH
RY4
C4
BLU
STIRRER
MOTOR
NOTES:
1. Circuits / Wire Colors subject to change without notice.
2. Terminal that located to the right side on the lamp socket's back view
must be connected to neutral wire.
3. Only certain models use the absolute humidity sensor
Figure O-2. Oven Schematic-Cooking Condition
9
MAGNETRON
C3
WHT
BLK
L
WHT
WHT
WHT
GRN
BLU
RED
YLW B1
BLK
COM N.O.
E2
HOOD FAN
THERMAL
CUT OUT
GND
RED
BLK
FAN
MOTOR
WITH
TEMP. FUSE
LVT
RED
RED
N
C1
COM
N.O.
PRIMARY
INTERLOCK
SWITCH
C3
RED A5
120VAC
60Hz.
OVEN
LAMP
ORG
BLK
RED
RED
CONTROL UNIT
H
GRN
RED
RED
ORG
RED
OVEN THERMAL
CUT OUT
FUSE
20A
SECONDARY
INTERLOCK
SWITCH
RED
BLK
BRN
BLK
RED
ORG
PMOR3021S
PMOR3021B
PMOR3021R
DESCRIPTION AND FUNCTION OF COMPONENTS
monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN MONITOR
FUSE TEST THE STOP SWITCH, PRIMARY
INTERLOCK SWITCH, SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH FOR
PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE").
NOTE: MONITOR FUSE AND SWITCH ARE REPLACED
AS AN ASSEMBLY
DOOR OPEN MECHANISM
The door is opened by pushing the open button on the
control panel, refer to the Figure D-1.
When the open button is pushed, the open button pushes up
the open lever, and then the open lever pushes up the latch
head. The latch heads are moved upward and released from
latch hook. Now the door will open.
Latch heads
Latch hook
THERMAL CUT-OUT (HOOD )
Stop switch
This thermal cut-out located on the right base plate. It is
designed to automatically turn on the hood fan motor
whenever the hot air rising from the conventional range
below causes the temperature at the thermal cut-out to rise
o
o
to 140 F (60 C) or higher, thus removing this hot air from
around microwave oven. When the temperature around the
o
o
thermal cut-out drops to 113 F (45 C) or lower, the thermal
cut-out shuts off the hood fan motor.
Primary
interlock switch
Door
Monitor switch
Secondary
interlock switch
THERMAL CUT-OUT (OVEN )
Open lever
This thermal cut-out is located on the top of the oven cavity.
It is designed to prevent damage to the oven unit if the food
in the oven catches fire due to overheating produced by
improper setting of cooking time or failure of control unit.
Under normal operation, the thermal cut-out remains
o
closed. However, the thermal cut-out will open at 293 F
o
(145 C) causing the oven to shut down.
Figure D-1. Door Open Mechanism
STOP, PRIMARY INTERLOCK AND SECONDARY
INTERLOCK SWITCHES
The secondary interlock switch is mounted in the lower
position of the latch hook and the stop switch is mounted in
the upper position of the latch hook. The primary interlock
switch is also in the upper position of the latch hook. They
are activated by the latch heads on the door. When the door
is opened, the switches interrupt the circuit to all components. A cook cycle cannot take place until the door is firmly
closed thereby activating both interlock switches.
COOLING FAN MOTOR
The cooling fan motor drives a blade which draws external
cool air. This cool air is directed through the air vanes
surrounding the magnetron and cools the magnetron. This
air is channelled through the oven cavity to remove steam
and vapors given off from the heating foods. It is then
exhausted through the exhausting air vents at the oven
cavity.
MONITOR SWITCH
The monitor switch is activated (the contacts opened) by the
latch head on the door while the door is closed. The switch
is intended to render the oven inoperative by means of
blowing the monitor fuse when the contacts of the primary
interlock switch and secondary interlock switch fail to open
when the door is opened.
HOOD FAN MOTOR
The hood fan motor is a two-speed, single-phase, double
pole induction type, requiring a hood fan capacitor. It is
located outside the upper rear part of the oven cavity, is to
remove, from around the oven, hot air rising from the
conventional electric or gas range over which it is installed.
This air is then expelled either vertically or horizontally
through the customer supplied duct system, or discharged
back into the kitchen.
Functions:
1. When the door is opened, the monitor switch contact
close (to the ON condition) due to their being normally
closed. At this time the primary interlock switch and
secondary interlock switch are in the OFF condition
(contacts open) due to their being normally open contact
switches. And the contacts of relay (RY1) are in the ON
condition (contacts close).
2. As the door goes to a closed position, the monitor switch
contacts are first opened and the stop switch contacts
close, and then the primary interlock switch and the
secondary interlock switch contacts close. (On opening
the door, each of these switches operate inversely.)
3. If the door is opened, and the primary interlock switch
and secondary interlock switch contacts fail to open, the
monitor fuse blows simultaneously with closing of the
STIRRER MOTOR
The stirrer motors drive the stirrer fans to stir the microwave
radiation from the waveguide.
HOOD LAMP
The hood lamps are mounted at the hood lamp angle. The
hood lamps can be turned off and on by touching the Light
Options pad. And also the brightness can be varied to high
or low by touching the Light Options pad.
10
PMOR3021S
PMOR3021B
PMOR3021R
TROUBLESHOOTING GUIDE
Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.
When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many
of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which
will be found in the "Test Procedure "section.
IMPORTANT: If the oven becomes inoperative because of a blown monitor fuse, check the monitor switch, relay (RY1)
primary interlock switch and secondary interlock switch before replacing the monitor fuse. If monitor fuse
is replaced, the monitor switch must also be replaced. Use part FFS-BA016/KIT as an assembly.
IMPORTANT: Whenever troubleshooting is performed with the power supply cord disconnected. It may in, some cases,
be necessary to connect the power supply cord after the outer case has been removed, in this event,
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. To discharge high voltage capacitor, waite for 60 seconds.
4. Disconnect the leads to the primary of the inverter unit.
5. Ensure that the leads remain isolated from other components and oven chassis by using insulation tape.
6. After that procedure, reconnect the power supply cord.
When the testing is completed
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. To discharge high voltage capacitor, waite for 60 seconds.
4. Reconnect all leads removed from components during testing.
5. Reinstall the outer case (cabinet).
6. Reconnect the power supply cord after the outer case is installed.
7. Run the oven and check all functions.
11
12
SENSOR
COOKING
CONDITION
MICROWAVE
COOKING
CONDITION
IDLE
CONDITION
OFF
CONDITION
POSSIBLE CASE AND
DEFECTIVE PARTS
The oven Stops and "ERROR" is displayed or does not end during Sensor
Cooking condition. (Oven does not shut off after a cup of water is boiling by
Sensor Cooking.)
Oven stops at 32 seconds after starting.
Oven does not go into cook cycle when START pad is touched
Oven seems to be operating but little or no heat is produced in oven load.
(Food incompletely cooked or not cooked at all at end of cook cycle.)
Oven goes into a cook cycle but extremely uneven heating is produced in
oven load (food).
Variable cooking does not operate properly except Cooking Power 100% mode.
Stirrer motor does not operate. (Other parts operate.)
Oven goes into EASY DEFROST but food is not defrosted well.
Oven lamp does not light in cook cycle. (But it does light when door is opened.)
Fan motor does not operate. (Oven lamp and strrer motor operate.)
Hood fan motor does not rotate at all with touched Fan pad.
Speed of the hood fan motor does not change when the Fan Options pad is
touched for this function.
Temperature of oven base seems more than 140°F (60°C) because of operation
of the range below. But hood fan motor does not turn on automatically. (Normally, food fan motor should be operating at low speed.)
Hood lights do not turn on when Light pad is pressed.
Oven lamp does not light with door is opened.
Hood fan motor operates when power cord is first plugged into wall receptacle.
Home fuse blows when power cord is plugged into wall receptacle.
Monitor fuse blows when power cord is plugged into wall receptacle.
Display does not illuminate when power cord is first plugged into wall receptacle.
Display does not operate properly when STOP/CLEAR key is touched. (The
time of day should appear on the display with beep sound during normal condition.)
PROBLEM
P
CK
CK
RE
CK
CK
RE
RE
RE
RE
O
N
M
L
L
L
L
K
J
I
H
G
F
E
D
D
C
B
A
CONDITION
TEST PROCEDURE
PMOR3021S
PMOR3021B
PMOR3021R
CK = Check / RE = Replace
NOISE FILTER
LOW VOLTAGE
NO POWER AT OUTLET
SHORTED IN POWER CORD
OPENED OR SHORTED WIRING
HOOD MOTOR CAPACITOR
HOOD LAMP OR SOCKET
STIRRER MOTOR
FAN MOTOR
OVEN LAMP OR SOCKET
HUMIDITY SENSOR (R2120J)
FOIL PATTERN ON P.W.B.
EASY DEFROST
RELAY (RY-4)
RELAY (RY-3)
RELAY (RY-5, RY-6)
RELAY (RY-1)
KEY UNIT
CONTROL UNIT
HOOD FAN MOTOR
HOOD THERMAL CUT-OUT
MONITOR FUSE
MONITOR SWITCH
STOP SWITCH
PRIMARY INTERLOCK SWITCH
SECONDARY INTERLOCK SWITCH
OVEN THERMAL CUT-OUT
INVERTER UNIT
MAGNETRON
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
A
COMPONENT TEST
MAGNETRON ASSEMBLY TEST
1.
2.
3.
4.
5.
6.
7.
8.
9.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check across
the magnetron filament leads should indicate less than 1 ohm.
To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament leads and
chassis ground. This test should indicate an infinite resistance. If there is little or no resistance the
magnetron is grounded and must be replaced.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
MICROWAVE OUTPUT POWER
The following test procedure should be carried out with the microwave oven in a fully assembled condition
(outer case fitted).
HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION SHOULD BE
OBSERVED.
Power output of the magnetron can be measured by performing a water temperature rise test. This test should
only be used if above tests do not indicate a faulty magnetron and there is no defect in the following
components or wiring: inverter unit. This test will require a 16 ounce (453cc) measuring cup and an accurate
mercury thermometer or thermocouple type temperature tester. For accurate results, the following procedure
must be followed carefully:
1. Fill the measuring cup with 16 oz. (453cc) of tap water and measure the temperature of the water with a
thermometer or thermocouple temperature tester. Stir the thermometer or thermocouple through the water
until the temperature stabilizes. Record the temperature of the water.
2. Place the cup of water in the oven. Operate oven at POWER 10(HIGH) selecting more than 60 seconds
cook time. Allow the water to heat for 60 seconds, measuring with a stop watch, second hand of a watch
or the digital read-out countdown.
3. Remove the cup from the oven and again measure the temperature, making sure to stir the thermometer
or thermocouple through the water until the maximum temperature is recorded.
4. Subtract the cold water temperature from the hot water temperature. The normal result should be 39.2 to
63oF(21.8 to 35oC) rise in temperature. If the water temperatures are accurately measured and tested for
the required time period the test results will indicate if the magnetron tube has low power output (low rise
in water temperature) which would extend cooking time or high power output (high rise in water
temperature) which would reduce cooking time. Because cooking time can be adjusted to compensate
for power output, the magnetron tube assembly should be replaced only if the water temperature rise test
indicates a power output well beyond the normal limits. The test is only accurate if the power supply line
voltage is 120 volts and the oven cavity is clean.
B
INVERTER UNIT TEST
WARNING: DO NOT TOUCH THE COMPONENTS OF THE INVERTER UNIT WHILE INVERTER
UNIT IS ENERGIZED. IT IS DANGEROUS BECAUSE THIS HAS HIGH VOLTAGE
COMPONENTS.
CAUTION: DO NOT OPERATE INVERTER UNIT BY ITSELF.
CAUTION: DO NOT CONNECT THE OVEN TO WALL OUTLET WITHOUT THE OUTER CASE
INSTALLED.
Before checking the inverter unit, curry out following 4 steps.
1.
2.
3.
4.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
Make sure that the wire leads and the connectors are connected correctly to the inverter unit, control unit
and magnetron.
13
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
Chart for checking the defective inverter unit
No power at full power output cooking
YES
Magnetron is defective.
NO
Exchange the Inverter unit
Exchange the magnetron.
Brown monitor fuse
The secondary interlock switch, primary interlock
NO
switch and the monitor switch are operating properly.
Check the switches according to
the switch Test Procedure
YES
Exchange the Inverter unit
C
OVEN THERMAL CUT-OUT TEST
1.
2.
3.
4.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
A continuity check across the thermal cut-out terminals should indicate a closed circuit unless the
temperature of the thermal cut-out reaches approximately 293oF(145oC).
An open thermal cut-out indicates overheating of the oven, exchange the oven thermal cut-out and
check inside of oven cavity and for improper setting of cooking time or operation of control unit. Check
for restricted air flow through the vent holes of the oven cavity, especially the cooling fan and air guide.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
CAUTION: IF THE THERMAL CUT-OUT INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE, REPLACE THERMAL CUT-OUT.
D
PRIMARY INTERLOCK SWITCH AND SECONDARY INTERLOCK SWITCH TEST
1.
2.
3.
4.
5.
6.
7.
8.
E
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal
of the switch. The meter should indicate an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the primary interlock switch or secondary
interlock switch.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
STOP SWITCH TEST
STOP SWITCH
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
14
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
4. Isolate the switch and connect the ohmmeter to the common (COM.) and normally open (NO) terminal
of the switch. The meter should indicate an open circuit with the door open and a closed circuit with
the door closed. If improper operation is indicated, replace the stop switch.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
NOTE: If the stop switch contacts fail in the open position and the door is closed, the cooling fan motor,
stirrer motor and oven light will be activated by RY1.
F
MONITOR SWITCH TEST
1.
2.
3.
4.
5.
6.
7.
8.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
Before performing this test, make sure that the secondary interlock switch and the primary interlock
switch are operating properly, according to the above Switch Test Procedure. Disconnect the wire
lead from the monitor switch (COM) terminal. Check the monitor switch operation by using the
ohmmeter as follows. When the door is open, the meter should indicate a closed circuit. When the
monitor switch actuator is pushed by a screw driver through the lower latch hole on the front plate
of the oven cavity with the door opened (in this condition the plunger of the monitor switch is pushed
in), the meter should indicate an open circuit. If improper operation is indicated, the switch may be
defective. After testing the monitor switch, reconnect the wire lead to the monitor switch (COM)
terminal and check the continuity of the monitor circuit.
Reconnect all leads removed from
Black
White /Blue
components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord
after the outer case is installed.
Screw Driver
Run the oven and check all
Monitor
Switch
functions.
Ohmmeter
Secondary
Interlock
Switch
G
BLOWN MONITOR FUSE TEST
1.
2.
3.
4.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
If the monitor fuse is blown when the door is opened, check the primary interlock switch, secondary
interlock switch and monitor switch according to the "TEST PROCEDURE" for those switches before
replacing the blown monitor fuse.
CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE, TEST THE PRIMARY INTERLOCK
SWITCH, SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH FOR PROPER
OPERATION.
If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch must
be replaced with "monitor fuse and monitor switch assembly" part number FFS-BA016/KIT, even if
the monitor switch operates normally. The monitor fuse and monitor switch assembly is comprised
of a 20 ampere fuse and switch.
5. Reconnect all leads removed from components during testing.
6. Re-install the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
15
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
H
COMPONENT TEST
HOOD THERMAL CUT-OUT TEST
1.
2.
3.
4.
5.
6.
7.
8.
I
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
A continuity check across the thermal cut-out terminals should indicate an open circuit unless the
temperature of the thermal cut-out reaches approximately 140oF(60oC) or more. At that temperature, the
contacts will close. The thermal cut-out opens automatically at approximately 113oF(45oC).
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
HOOD FAN MOTOR TEST
1.
2.
3.
4.
5.
6.
7.
8.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
If the motor does not turn, touch the FAN HI/LO pad once (set hood fan motor power "HIGH") and check
voltage between pins "1" and "2" (Blue and Black wires) of the 6 pin connector. If 120 Volts appear and
the hood capacitor is good, replace the hood fan assembly. If 120 Volts does not appear, check the motor
circuit. The resistance values of motor terminals are as follows:
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
Resistance between;
YLW
BLU
1
4
HOOD FAN
CAPACITOR
32 Ω
5
20 Ω
10 Ω
BLU (1)
BLK (2)
BLU (1)
BLK (2)
WHT (3)
AND
AND
AND
AND
AND
YLW (4) =
YLW (4) =
BLK (2) =
WHT (3) =
RED (5) =
0
32
32
10
20
Ω (Shorted)
Ω
Ω
Ω
Ω
BLU BLK WHT
1
2
3
2
BLK
RED
3
WHT
6-PIN CONNECTOR
OF HOOD FAN MOTOR
4
5
YLW RED
J
TOUCH CONTROL PANEL ASSEMBLY TEST
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike
conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter and
ohmmeter. In this service manual, the touch control panel assembly is divided into two units, Control Unit and
Key Unit, and also the Control Unit is divided into two units, LSI Unit and Power Unit, and troubleshooting by
unit replacement is described according to the symptoms indicated.
Before testing,
1) Disconnect the power supply cord, and then remove outer case. Refer to procedure of “HOOD
LOUVER REMOVAL”, “REMOVAL OF OVEN FROM WALL ” and “ OUTER CASE REMOVAL”.
2) Open the door and block it open.
3) To discharge high voltage capacitor, wait for 60 seconds.
4) Remove seven (7) screws holding the hood intake duct R to the oven cavity top plate, oven cavity
flange, fun duct, magnetron duct and the base plate R. And remove the hood intake duct R.
5) Disconnect the leads to the primary of the inverter unit.
6) Ensure that these leads remain isolated from other components and oven chassis by using insulation
tape.
16
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
1. Key Unit.
NOTE ;
1) Check key unit ribbon connection before replacement.
2) Re-install the hood intake duct R with seven (7) screws.
3) Re-install the outer case (cabinet).
4) Reconnect the power supply cord after the outer case is installed.
5) Run the oven and check all functions.
The following symptoms indicate a defective key unit.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching a number pad, two figures or more are displayed.
c) When touching the pads, sometimes a pad produces no signal.
If the key unit is defective.
1) Disconnect the power supply cord, and then remove outer case.
2) Open the door and block it open.
3) To discharge high voltage capacitor, wait for 60 seconds.
4) Replace the key unit.
5) Reconnect all leads removed from components during testing.
6) Re-install the outer case (cabinet).
7) Reconnect the power supply cord after the outer case is installed.
8) Run the oven and check all functions.
2. Control Unit.
The following symptoms indicate a defective control unit. Before replacing the control unit, perform the
Key unit test (Procedure K) to determine if control unit is faulty.
2-1 In connection with pads.
a) When touching the pads, a certain group of pads do not produce a signal.
b) When touching the pads, no pads produce a signal.
2-2 In connection with indicators
a) At a certain digit, all or some segments do not light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
2-3 Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Clock does not operate properly.
c) Cooking is not possible.
When testing is completed,
1) Disconnect the power supply cord.
2) Open the door and block it open.
3) To discharge high voltage capacitor, wait for 60 seconds.
4) Reconnect all leads removed from components during testing.
5) Re-install the hood intake duct R.
6) Re-install the outer case (cabinet).
7) Reconnect the power supply cord after the outer case is installed.
8) Run the oven and check all functions.
K
KEY UNIT TEST
1.
2.
3.
4.
5.
Disconnect the power supply cord.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
Remove the control panel assembly.
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable is
making good contact, verify that the stop switch operates properly; that is the contacts are closed when
the door is closed and open when the door is open. If the stop switch is good, disconnect the flat ribbon
cable that connects the key unit to the control unit and make sure the stop switch is closed (either close
the door or short the stop switch connecter). Use the Key unit matrix indicated on the control panel
17
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
62
1
L
G4
G3
61
59
58
57
56
55
54
53
52
G5
G6
G7
G8
G9
G10
G11
G12
0
5
4
3
Cook
Dinner
Easy
Defrost
8
1
2
Breakfast
Menu
6
7
9
Soften
Warm
Reheat
START
EASY MINUTE
POWER
LEVEL
G2
60
G1
6.
7.
8.
9.
schematic and place a jumper wire between the pins that correspond to the STOP/CLEAR pad making
momentary contact. If the control unit responds by clearing with a beep the key unit is faulty and must be
replaced. If the control unit does not respond, it is faulty and must be replaced. If a specific pad does not
respond, the above method may be used (after clearing the control unit) to determine if the control unit or
key pad is at fault.
Reconnect all leads removed from components during testing.
Re-install the control panel assembly.
Reconnect the power supply cord.
Run the oven and check all functions.
STOP
Popcorn
CLEAR
Menu
Help
Guide
Melt
Lunch
Menu
Keep
Warm
FAN
HI / LO
Timer
Clock
LIGHT
HI / LO
RELAY TEST
1. Disconnect the power supply cord, and then remove outer case. Refer to procedure of “HOOD LOUVER
REMOVAL”, “REMOVAL OF OVEN FROM WALL” and “OUTER CASE REMOVAL”.
2. Open the door and block it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. Remove the hood intake duct R.
5. Disconnect the leads to the primary of the inverter unit.
6. Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.
7. After that procedure, re-connect the power supply cord.
8. Check voltage between the Pin No. 3 of the 3 pin connector (C) and the normal open terminal of the relay
RY1 on the control unit with an A.C. voltmeter.
The meter should indicate 120 volts, if not check oven circuit.
RY1, RY3, RY4, RY5 and RY6 Relay Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated ....................... Defective relay.
DC. voltage not indicated ................. Check diode which is connected to the relay coil. If diode is
good, control unit is defective.
RELAY SYMBOL
OPERATIONAL VOLTAGE
CONNECTED COMPONENTS
RY1
Approx. 25.0V D.C.
Inverter unit/ Oven lamp/ Fan motor/ Stirrer motor
RY3
Approx. 25.0V D.C.
Hood motor (High/ Low seclection)
RY4
Approx. 25.0V D.C.
Hood motor
RY5
Approx. 25.0V D.C.
Hood lamp
RY6
Approx. 25.0V D.C.
Hood lamp
9. Disconnect the power supply cord.
10. Open the door and block it open.
11. To discharge high voltage capacitor, wait for 60 seconds.
12. Reconnect all leads removed from components during testing.
13. Re-install the hood intake duct R.
14. Re-install the outer case (cabinet).
15. Reconnect the power supply cord after the outer case is installed.
M
EASY DEFROST TEST
(1) Open the door.
(2) Place one cup of water in the center of the turntable tray in the oven cavity.
(3) Touch the “EASY DEFROST” pad once. And then touch the number pad “ 2 ”.
(4) Touch the number pad “ 5 ”.
(5) Close the door.
18
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
(6) Touch the “ START ” button.
(7) The oven is in Easy defrost cooking condition.
(8) The oven will operate as follows.
Menu
1ST STAGE
2ND STAGE
Steaks/Chops
LEVEL
TIME
LEVEL
TIME
0.5lbs
40%
57sec.
40%
22sec.
(9) If improper operation is indicated, the control unit is probably defective and should be checked.
N
FOIL PATTERN ON THE PRINTED WIRING BOARD TEST
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on the PWB,
this foil pattern acts as a fuse.
1. Foil pattern check and repairs.
1) Disconnect the power supply cord.
2) Open the door and block it open.
3) To discharge high voltage capacitor, wait for 60 seconds.
4) Remove the control unit, referring to the procedure of “ CONTROL PANEL ASSEMBLY, CONTROL
UNIT AND KEY UNIT REMOVAL ”.
5) Follow the troubleshooting guide given below for repair.
STEPS
OCCURRENCE
CAUSE OR CORRECTION
1
Only pattern at “a” is broken.
*Insert jumper wire J1 and solder.
2
Pattern at “a” and “b” are broken.
*Insert the coil RCILF2003YAZZ between “c” and “d”.
6) Make a visual inspection of the varistor. Check
for burned damage and examine the
transformer with a tester for the presence of
layer short-circuit (check the primary coil
resistance which is approximately 160Ω ±
10%). If any abnormal condition is detected,
replace the control unit.
7) Reconnect all leads removed from components
during testing.
8) Re-install the control unit to the control panel
and re-install the control panel to the oven.
9) Reconnect the power supply cord.
10) Run the oven and check all functions.
2. Follow the troubleshooting guide given below, if indicator does not light up after above check and repairs
are finished.
1) Disconnect the power supply cord, and then remove outer case. Refer to procedure of “HOOD
LOUVER REMOVAL”, “REMOVAL OF OVEN FROM WAL ” and “OUTER CASE REMOVAL”.
2) Open the door and block it open.
3) To discharge high voltage capacitor, wait for 60 seconds.
4) Remove the hood intake duct R.
5) Disconnect the leads to the primary of the inverter unit.
6) Ensure that these leads remain isolated from other components and oven chassis by using insulation
tape.
7) After that procedure, re-connect the power supply cord.
8) Follow the troubleshooting guide given below for repair.
d
c
b
a
STEPS
OCCURRENCE
CAUSE OR CORRECTION
1
The rated AC voltage is not present between
the Pin No. 3 of the 3 pin connector (C) and
the normal open terminal of the relay RY1.
Check supply voltage and oven power cord.
2
The rated AC voltage is present at primary
side of low voltage transformer.
Low voltage transformer or secondary circuit defective.
Check and replace the control unit.
19
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
9)
10)
11)
12)
13)
14)
15)
16)
O
Disconnect the power supply cord.
Open the door and block it open.
To discharge high voltage capacitor, wait for 60 seconds.
Reconnect all leads removed from components during testing.
Re-install the hood intake duct R.
Re-install the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
HUMIDITY SENSOR TEST FOR R-2120J
Checking the initial sensor cooking condition
WARNING : The oven should be fully assembled before following procedure.
(1) The oven should be plugged in at least two minutes before sensor cooking.
o
o
(2) Room temperature should not exceed 95 F (35 C).
(3) The unit should not be installed in any area where heat and steam are generated. The unit should not be
installed, for example, next to a conventional surface unit. Refer to the “INSTALLATION INSTRUCTIONS”
of the operation manual.
(4) Exhaust vents are provided on the back of the unit for proper cooling and air flow in the cavity. To permit
adequate ventilation, be sure to install so as not to block these vents. There should be some space for air
circulation.
(5) Be sure the exterior of the cooking container and the interior of the oven are dry. Wipe off any moisture
with a dry cloth or paper towel.
(6) The Sensor works with food at normal storage temperature. For example, chicken pieces would be at
refrigerator temperature and canned soup at room temperature.
(7) Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings. The sensor
will detect the vapor given of by the spray and turn off before food is properly cooked.
(8) If the sensor has not detected the vapor of the food, ERROR will appear and the oven will shut off.
Water load cooking test
WARNING : The oven should be fully assembled before following procedure.
Make sure the oven has been plugged in at least two minutes before checking sensor cook operation. The
cabinet should be installed and screws tightened.
(1) Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.
(2) Place the container on the center of tray in the oven cavity.
(3) Close the door.
(4) Touch the TIMER/CLOCK once, the POWER LEVEL pad twice, the START pad once, the number pad
1 once and the number pad 4 once. Now, the oven is in the sensor cooking condition, and “ AH20 ”, “
SENSOR ” and “ COOK ” will appear in the display.
(5) The oven will operate for the first 32 seconds, without generating microwave energy.
NOTE: ERROR will appear if the door is opened or STOP/CLEAR pad is touched during first stage of sensor
cooking.
(6) After approximately 32 seconds, microwave energy is produced.
If ERROR is displayed or the oven does not turn off, replace the humidity sensor or check the control unit,
refer to explanation below. If the oven stops after 5 minutes and ERROR is displayed, the h umidity sensor
is normal. Check other parts except the Humidity sensor.
TESTING METHOD FOR HUMIDITY SENSOR AND/OR CONTROL UNIT
To determine if the sensor is defective, the simplest method is to replace it with a new replacement sensor.
(1) Disconnect the power supply cord, and then remove outer case.Refer to procedure of “HOOD LOUVER
REMOVAL”, “REMOVAL OF OVEN FROM WAL ” and “OUTER CASE REMOVAL”.
(2) Open the door and block it open.
(3) To discharge high voltage capacitor, waite for 60 seconds.
(4) Remove the humidity sensor.
(5) Install the new humidity sensor.
(6) Reconnect all leads removed from components during testing.
(7) Re-install the outer case (cabinet).
(8) Reconnect the power supply cord after the outer case is installed.
20
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
(9) Reconnect the oven to the power supply and check the sensor cook operation as follows:
9-1. Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.
9-2. Place the container on the center of tray in the oven cavity.
9-3. Close the door.
9-4. Touch the TIMER/CLOCK pad once, the POWER LEVEL pad twice, the START pad once, the
number pad 1 once and the number pad 4 once.
9-5. The control panel is in automatic Sensor operation.
9-6. The oven turns off automatically, and the time for detecting moisture will be displayed.
If new sensor dose not operate properly, the problem is with the control unit, and refer to explanation below.
CHECKING CONTROL UNIT
(1) Disconnect the power supply cord, and then remove outer case. Refer to procedure of “HOOD LOUVER
REMOVAL”, “REMOVAL OF OVEN FROM WAL ” and “OUTER CASE REMOVAL”.
(2) Open the door and block it open.
(3) To discharge high voltage capacitor, waite for 60 seconds.
(4) Disconnect the sensor connector that is mounted to control panel.
(5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.
(6) Disconnect the leads to the primary of the inverter unit.
(7) Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.
(8) After that procedure, re-connect the power supply cord.
(9) Check the sensor cook operation proceed as follows:
9-1. Touch the TIMER/CLOCK pad once, the POWER LEVEL pad twice, the START pad once and the
number pad 1 once and the number pad 4 once.
9-2. The control panel is in the sensor cooking operation.
9-3. After approximately 65 seconds, push plunger of select switch for more than 3 seconds. This
condition is same as judgement by humidity sensor.
9-4. After approximately 3 seconds, the display shows “ X X . X X ” which is the time for detecting
moisture.
If the above is not the case, the control unit is probably defective.
If the above is proper, the humidity sensor is probably defective.
(10) Disconnect the power supply cord, and then remove outer case.
(11) Open the door and block it open.
(12) To discharge high voltage capacitor, waite for 60 seconds.
(13) Disconnect the dummy resistor circuit from the sensor connector of control panel.
(14) Carry out necessary repair.
(15) Reconnect all leads removed from components during testing and repairing.
(16) Re-install the outer case (cabinet).
(17) Reconnect the power supply cord after the outer case is installed. Run the oven and check all functions.
(18) Carry out “Water load cooking test” again and ensure that the oven works properly.
Ω ± 1% 1/2W
R1, R2 : 22Ω
Ω
R3 : 4.3Ω ± 5% 1/4W
Ω ± 5% 1/4W
R4 : 1MΩ
Plunger
NC
NO
F-1
F-2
To connector (F)
on Control Unit.
1
2
3
COM
COM NO
R1
F-3
R2
CONNECTOR
R3
R4
Sensor Dummy Resistor Circuit
21
NC
PMOR3021S
PMOR3021B
PMOR3021R
TEST PROCEDURES
PROCEDURE
LETTER
P
COMPONENT TEST
NOISE FILTER TEST
1.
2.
3.
4.
5.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor.
Disconnect the leads to the primary of the power transformer.
Using an ohm-meter, check between the terminals as described in the following table:
SOURCE
NOISE FILTER UNIT
SOURCE
NOISE SUPPRESSION COIL
LINE CROSS CAPACITOR
TOR
0.22uF/ AC 250V
LINE BYPASS CAPACITOR
LINE BYPASS CAPACITOR
0.0033uF/ AC
0.0033uF/ AC
125V
125V
LOAD
MEASURING POINT
LOAD
INDICATION OF OHM-METER
Between source and source
Open Circuit
Between terminal source and load
Short Circuit
Between terminal source and load
Short Circuit
If incorrect readings are obtained, replace the noise filter.
6.
7.
8.
9.
Reconnect all leads removed from components during testing.
Re-install the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
22
PMOR3021S
PMOR3021B
PMOR3021R
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units
as shown in the touch control panel circuit.
3) Synchronizing Signal Circuit
The power source synchronizing signal is available in
order to compose a basic standard time in the clock
circuit. It incorporates a very small error because it works
on commercial frequency.
(1) Key Unit
(2) Control Unit (The Control unit consists of LSI Unit and
Power U nit)
4) Reset Circuit
A circuit to generate a signals which resetting the LSI to
the initial state when power is applied.
The principal functions of these units and the signals
communicated among them are explained below.
Key Unit
The key unit is composed of a matrix, signals generated in
the LSI are sent to the key unit through P20, P21, P22, P23,
P24, P25, P26 and P27.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through P43, P44,
P45 and P46 to perform the function that was requested.
5) Buzzer Circuit
The buzzer is responds to signals from the LSI to emit
audible sounds (key touch sound and completion sound).
6) Stop Switch
A switch to inform the LSI if the door is open or closed.
7) Relay Circuit
To drive the inverter unit, fan motor, stirrer motor, hood
motor, and light the oven lamp and hood lamp.
Control Unit
Control unit consists of LSI, power source circuit, synchronizing signal circuit, reset circuit, buzzer circuit, relay circuit
indicator circuit, back light circuit and humidity sensor
circuit.
8) Indicator Circuit
This circuit consists of 25 segments and 4 common
electrodes using a Light Crystal Display.
1) LSI
This LSI controls the key strobe signal, relay driving
signal for oven function and indicator signal.
9) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD1-LD5).
2) Power Source Circuit
This circuit generates voltages necessary for the control
unit from the AC line voltage.
In addition, the synchronizing signal is available in order
to compose a basic standard time in the clock circuit.
Symbol
VC
Voltage
-5.0V
10) Humidity Sensor Circuit
This circuit detects moisture of the cooking food to allow
its automatic cooking.
11) Inverter Unit Control Circuit
This is the circuit to control inverter unit.
Application
LSI(IC1)
23
PMOR3021S
PMOR3021B
PMOR3021R
DESCRIPTION OF LSI
LSI
The I/O signal of the LSI is detailed in the following table.
Pin No.
1-2
Signal
VL2-VL1
I/O
IN
3-5
AN7-AN5
IN
6
AN4
IN
7
8
AN3
AN2
OUT
IN
9
AN1
IN
10
AN0
IN
11
P57
OUT
Description
Power source voltage input terminal.
Standard voltage for LCD.
Terminal to change cooking input according to the Model.
By using the A/D converter contained in the LSI, DC voltage in accordance with the
Model in operation is applied to set up its cooking constant.
Temperature measurement input: MAGNETRON THERMISTOR.
By inputting DC voltage corresponding to thetemperature detected by the thermistor,
this input is converted into temperature by the A/D converter built into the SLI.
Back light circuit (Light emitting diodes) driving signal.
To input signal which communicates the door open/close information to LSI.
Door close “H” level signal (0V). Door open “L” level signal (-5V).
Humidity sensor input for R2120J.
This input is an analog input terminal from the humidity sensor circuit, and connected
to the A/D converter built into the LSI.
Used for initial balancing of the bridge circuit (humidity sensor). This input is an analog
input terminal from the humidity sensor circuit, and connected to the A/D converter built
into the LSI for R-2120J.
Oven lamp, fan motor stirrer motor and inverter unit driving signal
To turn on and off shut off relay (RY1). The
16.7 msec.
H : GND
square waveform voltage is delivered to the
RY1 driving circuit.
L : -5V
During cooking
12
P56
OUT
Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
0.1 sec.
H : GND
A
L : -5V
2.0 sec.
H : GND
B
L : -5V
13
14-18
19
P50
P54-P50
P47
OUT
OUT
OUT
Terminal not used.
Used for initial balancing of the bridge circuit (humidity sensor) for R2120J.
16.7 msec.
Power level data output signal for inverter unit.
The power level will be decided by the time ratio
of T1 and T2.
T1
20
P46
IN
21
P45
IN
22
P44
IN
23
P43
IN
24
INT0
IN
H : GND
L : -5V
T2
Signal coming from touch key.
When either G1 line on key matrix is touched, a corresponding signal out of P20 - P27
will be input into P46. When no key is touched, the signal is held at “H” level.
Signal similar to P46.
When either G2 line on key matrix is touched, a corresponding signal will be input into P45.
Signal similar to P46.
When either G3 line on key matrix is touched, a corresponding signal will be input into P44.
Signal similar to P46.
When either G4 line on key matrix is touched, a corresponding signal will be input into P43.
Signal synchronized with commercial power source frequency.
H : GND
This is the basic timing for time processing of LSI.
L : -5V
16.7 msec.
24
PMOR3021S
PMOR3021B
PMOR3021R
Pin No.
Signal
I/O
25
26
27
P41
P40
RESET
OUT
IN
IN
28
29
30
P71
P70
XIN
OUT
OUT
IN
31
XOUT
OUT
32
VSS
IN
33
P27
OUT
34
P26
OUT
35
P25
OUT
36
P24
OUT
37
P23
OUT
38
P22
OUT
39
P21
OUT
40
P20
OUT
41
P17
OUT
42
P16
OUT
43
P15
OUT
44
P14
OUT
P13-P12
SEG25
OUT
OUT
45-46
47
Description
Terminal not used.
Connected to GND through the pull-down resistor.
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied.
Clock signal is output to a memory IC (IC3).
Data signal is output to a memory IC (IC3).
Internal clock oscillation frequency input setting.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit with
respect to XOUT terminal.
Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
Power source voltage: -5.0V.
VC voltage of power source circuit input.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G5 line keys on key matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G6 line keys on key matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G7 line keys on key matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G8 line keys on key matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G9 line keys on key matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G10 line keys on key matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G11 line keys on key matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G12 line keys on key matrix is touched.
Hood lamp driving signal.
H : GND
OFF
To turn on and off relay(RY6). “L” level: During
L
ON
Hood lamp ON. “H” level: During Hood lamp OFF.
Hood lamp driving signal.
H : GND
OFF
To turn on and off relay(RY5). “L” level: During
L
ON
Hood lamp ON. “H” level: During Hood lamp OFF.
Hood motor high / low driving signal.
H : GND
OFF
To turn on and off relay(RY3). “L” level: During Hood
L
ON
motor high. “H” level: During Hood motor low.
Hood motor driving signal.
H : GND
OFF
To turn on and off relay(RY4). “L” level: During
L
ON
Hood motor on. “H” level: During Hood motor OFF.
Terminal not used.
Terminal not used.
25
PMOR3021S
PMOR3021B
PMOR3021R
Pin No.
Signal
I/O
Description
48-72
SEG24-SEG0
OUT
Segment data signal.
Connected to LCD.
The relation between signals are as follows:
LSI signal (Pin No.)
LCD (Pin No.) LSI signal (Pin No.)
LCD (Pin No.)
SEG 24 (48) ----------------- SEG24 (29)
SEG 11 (61) ------------------ SEG11 (16)
SEG 23 (49) ----------------- SEG23 (28)
SEG 10 (62) ------------------ SEG10 (15)
SEG 22 (50) ----------------- SEG22 (27)
SEG 9 (63) ------------------ SEG 9 (14)
SEG 21 (51) ----------------- SEG21 (26)
SEG 8 (64) ------------------ SEG 8 (13)
SEG 20 (52) ----------------- SEG20 (25)
SEG 7 (65) ------------------ SEG 7 (12)
SEG 19 (53) ----------------- SEG19 (24)
SEG 6 (66) ------------------ SEG 6 (11)
SEG 18 (54) ----------------- SEG18 (23)
SEG 5 (67) ------------------ SEG 5 (10)
SEG 17 (55) ----------------- SEG17 (22)
SEG 4 (68) ------------------ SEG 4 ( 9)
SEG 16 (56) ----------------- SEG16 (21)
SEG 3 (69) ------------------ SEG 3 ( 8)
SEG 15 (57) ----------------- SEG15 (20)
SEG 2 (70) ------------------ SEG 2 ( 7)
SEG 14 (58) ----------------- SEG14 (19)
SEG 1 (71) ------------------ SEG 1 ( 6)
SEG 13 (59) ----------------- SEG13 (18)
SEG 0 (72) ------------------ SEG 0 ( 5)
SEG 12 (60) ----------------- SEG12 (17)
73/74
75
76
77
78
79
80
VCC/VREF
AVSS
COM3
COM2
COM1
COM0
VL3
IN
IN
OUT
OUT
OUT
OUT
IN
Connected to GND.
Connected to VC.
Common data signal.
Connected to LCD signal COM4.
Common data signal.
Connected to LCD signal COM3.
Common data signal.
Connected to LCD signal COM2.
Common data signal.
Connected to LCD signal COM1.
Power source voltage input terminal.
Standard voltage for LCD.
26
PMOR3021S
PMOR3021B
PMOR3021R
HUMIDITY SENSOR CIRCUIT
(1) Structure of Humidity Sensor
The humidity sensor includes two thermistors as shown
in the illustration. One thermistor is housed in the closed
vessel filled with dry air while another in the open vessel.
Each sensor is provided with the protective cover made
of metal mesh to be protected from the external airflow.
As the sensor cooking proceeds, the food is heated to
generate moisture by which the resistance balance of
the bridge circuit is deviated to increase the voltage
available at AN1 terminal of the LSI.
Then the LSI observes that voltage at AN1 terminal and
compares it with its initial value, and when the comparison
rate reaches the preset value (fixed for each menu to be
cooked), the LSI causes the unit to stop sensor cooking;
thereafter, the unit goes in the next operation
automatically.
When the LSI starts to detect the initial voltage at AN1
terminal 16 seconds after the unit has been put in the
Sensor Cooking mode, if it is not possible to balance the
bridge circuit due to disconnection of the humidity
sensor, ERROR will appear on the display and the
cooking is stopped.
Thermistors
Sensing part
(Closed vessel)
(2) Operational Principle of Humidity Sensor
The figure below shows the basic structure of a humidity
sensor. A bridge circuit is formed by two thermistors and
two resistors (R1 and R2).
The output of the bridge circuit is to be amplified by the
operational amplifier.
Each thermistor is supplied with a current to keep it
heated at about 150oC (302oF), the resultant heat is
dissipated in the air and if the two thermistors are placed
in different humidity conditions they show different
degrees of heat conductivity leading to a potential
difference between them causing an output voltage
from the bridge circuit, the intensity of which is increased
as the absolute humidity of the air increases. Since the
output is very minute, it is amplified by the operational
amplifier.
R1
+
S
R3
R2
C. Thermistor in
closed vessel
S. Thermistor in
open vessel
Output
voltage
S : Thermistor
open vessel
C : Thermistor
closed vessel
18
R99
300k
17
R100
150k
16
R101
75k
15
R102
37.4k
14
R97
S
0.1
uF
R91
3.32k R92
1.8k
8 7 6 5
1 2 3 4
IC2
R93
360k
VA : -15V
Absolute humidity (g/m 2 )
(3) Detector Circuit of Humidity Sensor Circuit
This detector circuit is used to detect the output voltage
of the humidity circuit to allow the LSI to control sensor
cooking of the unit. When the unit is set in the sensor
cooking mode, 16 seconds clearing cycle occurs than
the detector circuit starts to function and the LSI observes
the initial voltage available at its AN1 terminal.
With this voltage given, the switches SW1 to SW5 in the
LSI are turned on in such a way as to change the
resistance values in parallel with R98 ~ R102. Changing
the resistance values results in that there is the same
potential at both F-3 terminal of the humidity sensor and
AN0 terminal of the LSI. The voltage of AN1 terminal will
indicate about -2.5V. This initial balancing is set up
about 16 seconds after the unit is put in the Sensor
Cooking mode.
27
VA : -15V
SW1
P50
P51
P52
P53
P54
47k
D90
VC : -5V
SW4
SW5
LSI
(IC1)
C92
R95
SW2
SW3
AN0
0.01uF
0.1uF
R94
15k
R90
F-2
C91
F-1
C
R96
F-3
3.57k
0.01uF
10
C93
47k
Absolute humidity vs,
output voltage characteristic
Operational
amplifier
620k
R98
Output voltage
C
1) Humidity sensor circuit
C90
ventilation opening for sensing
Sensing part
(Open vessel)
9
AN1
PMOR3021S
PMOR3021B
PMOR3021R
SERVICING
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the
circuits. When handling these parts, the following
precautions should be strictly followed. CMOS LSI have
extremely high impedance at its input and output
terminals. For this reason, it is easily influenced by the
surrounding high voltage power source, static electricity
charge in clothes, etc. and sometimes it is not fully
protected by the built-in protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly wrap them in
aluminium foil. Also wrap all PW boards containing them
in aluminium foil.
2) When soldering, ground the technician as shown in the
figure and use grounded soldering iron and work table.
repair all the controls (sensor-related ones included) of
the touch control panel while keeping it connected to the
oven.
B. On some models, the power supply cord between the
touch control panel and the oven proper is long enough
that they may be separated from each other. For those
models, it is possible to check and repair the controls of
the touch control panel while keeping it apart from the
oven proper; in this case you must short both ends of the
door sensing switch (on PWB) of the touch control panel
with a jumper, which activates an operational state that
is equivalent to the oven door being closed. As for the
sensor-related controls of the touch control panel,
checking them is possible if dummy resistor(s) with
resistance equal to that of the controls are used.
(2) Servicing the touch control panel with power supply
from an external power source:
Disconnect the touch control panel completely from the
oven proper, and short both ends of the door sensing
switch (on PWB) of the touch control panel, which
activates an operational state that is equivalent to the
oven door being closed. Connect an external power
source to the power input terminal of the touch control
panel, then it is possible to check and repair the controls
of the touch control panel it is also possible to check the
sensor-related controls of the touch control panel by
using the dummy resistor(s).
approx. 1M ohm
2. Servicing of Touch Control Panel
We describe the procedures to permit servicing of the
touch control panel of the microwave oven and the
precautions you must take when doing so. To perform
the servicing, power to the touch control panel is available
either from the power line of the oven itself or from an
external power source.
(1) Servicing the touch control panel with power supply
of the oven:
CAUTION:
THE HIGH VOLTAGE PARTS OF THE MICROWAVE
OVEN IS STILL LIVE DURING SERVICING AND
PRESENTS A HAZARD.
Therefore, before checking the performance of the touch
control panel,
1) Disconnect the power supply cord, and then remove
outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Disconnect the leads to the primary of the power
transformer.
5) Ensure that these leads remain isolated from other
components and oven chassis by using insulation
tape.
6) After that procedure, re-connect the power supply
cord.
After checking the performance of the touch control panel,
1) Disconnect the power supply cord.
2) Open the door and block it open.
3) Re-connect the leads to the primary of the inverter
unit.
4) Re-install the outer case (cabinet).
5) Re-connect the power supply cord after the outer
case is installed.
6) Run the oven and check all functions.
A. On some models, the power supply cord between the
touch control panel and the oven itself is so short that the
two can’t be separated. For those models, check and
3. Servicing Tools
Tools required to service the touch control panel
assembly.
1) Soldering iron: 30W
(It is recommended to use a soldering iron with a
grounding terminal.)
2) Oscilloscope: Single beam, frequency range: DC-10MHz
type or more advanced model.
3) Others: Hand tools
4. Other Precautions
1) Before turning on the power source of the control unit,
remove the aluminium foil applied for preventing static
electricity.
2) Connect the connectors of the key unit to the control unit
being sure that the lead wires are not twisted.
3) After aluminium foil is removed, be careful that abnormal
voltage due to static electricity etc. is not applied to the
input or output terminals.
4) Attach connectors, electrolytic capacitors, etc. to PWB,
making sure that all connections are tight.
5) Be sure to use specified components where high precision
is required.
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PRECAUTIONS FOR USING LEAD-FREE SOLDER
1. Employing lead-free solder
The "Control unit PWB and Inverter unit PWB" of this model employs lead-free solder. This is indicated by the "LF"
symbol printed on the PWB and in the service manual. The suffix letter indicates the alloy type of the solder.
Example:
Sn-Ag-Cu
Indicates lead-free solder of tin, silver and copper.
2. Using lead-free wire solder
When repairing a PWB with the "LF" symbol, only lead-free solder should be used. (Using normal tin/lead alloy solder
may result in cold soldered joints and damage to printed patterns.)
As the melting point of lead-free solder is approximately 40oC higher than tin/lead alloy solder, it is recommend that a
dedicated bit is used, and that the iron temperature is adjusted accordingly.
3. Soldering
As the melting point of lead-free solder (Sn-Ag-Cu) is higher and has poorer wettability, (flow), to prevent damage to
the land of the PWB, extreme care should be taken not to leave the bit in contact with the PWB for an extended period
of time. Remove the bit as soon as a good flow is achieved. The high content of tin in lead free solder will cause premature
corrosion of the bit. To reduce wear on the bit, reduce the temperature or turn off the iron when it is not required.
Leaving different types of solder on the bit will cause contamination of the different alloys, which will alter their
characteristics, making good soldering more difficult. It will be necessary to clean and replace bits more often when using
lead-free solder. To reduce bit wear, care should be taken to clean the bit thoroughly after each use.
29
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PMOR3021R
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
WARNING AGAINST HIGH VOLTAGE:
Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may
result in severe, possibly fatal, electric shock.
(Example)
Magnetron, Inverter Unit, High Voltage Harness etc..
WARNING:
Avoid possible exposure to microwave energy. Please follow the instructions below before
operating the oven.
1. Disconnect the power supply cord.
2. Make sure that a definite” click” can be heard when the
microwave oven door is unlatched. (Hold the door in a
closed position with one hand, then push the door open
button with the other, this causes the latch leads to rise,
it is then possible to hear a “click’ as the door switches
operate.)
3. Visually check the door and cavity face plate for damage
(dents, cracks, signs of arcing etc.).
1.
2.
3.
4.
5.
6.
Door does not close firmly.
Door hinge, support or latch hook is damaged.
The door gasket or seal is damaged.
The door is bent or warped.
There are defective parts in the door interlock system.
There are defective parts in the microwave generating
and transmission assembly.
7. There is visible damage to the oven.
Do not operate the oven:
1. Without the RF gasket (Magnetron).
2. If the wave guide or oven cavity are not intact.
3. If the door is not closed.
4. If the outer case (cabinet) is not fitted.
Carry out any remedial work that is necessary before
operating the oven.
Do not operate the oven if any of the following conditions
exist;
WARNING FOR WIRING
To prevent an electric shock, take the following precautions.
1. Before wiring,
1) Disconnect the power supply cord.
2) Open the door block it open.
3) To discharge the high voltage capacitor, wait for 60
seconds.
2. Don’t let the wire leads touch to the followiong parts;
1) High voltage parts:
Magnetron and Inverter unit.
2) Hot parts:
Oven lamp, Hood lamps, Magnetron, Invrter unit and
Oven cavity.
3) Sharp edge: All parts
(Bottom plate, Oven cavity, Waveguide flange,
Chassis support and other metallic plate.)
4) Movable parts (to prevent a fault)
Fan blade, Fan motor, Switch, Open lever, Open
button, Stirrer motors, Stirrer fans, Door parts.
3. Do not catch the wire leads in the outer case cabinet.
4. Insert the positive lock connector until its pin is locked
and make sure that the wire leads do not come off even
if the wire leads are pulled.
5. To prevent an error function, connect the wire leads
correctly, referring to the Pictorial Diagram.
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANAL PARTS, DOOR PARTS’, when carrying out any of
the following removal procedures:
THE FOLLOWING ADJUSTMENTS OR COMPONENT REPLACEMENT CAN BE PERFORMED
WITHOUT REMOVING THE OVEN FROM THE WALL
1. Oven lamp, hood lamps, hood lamp sockets, grease
filter and charcoal filter.
2. Base cover, hood lamp glass assembly, bottom sush.
3. Stirrer motors.
4. Hood louver.
5.
6.
7.
8.
9.
Control panel assembly or components.
Table tray assembly
Stirrer fan
Antenna plate assembly
Control unit
HOOD LOUVER REMOVAL
3. To discharge the high voltage capacitor, wait for 60
seconds.
1. Disconnect the power supply cord.
2. Open the door and block it open.
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PMOR3021S
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PMOR3021R
4. Remove the three (3) screws holding the hood louver to
the oven cavity front face plate.
5. Pull the hood louver from the oven cavity by pushing the
right and left tabs of the hood louver to remove.
6. Now, the hood louver is free.
Left tab
Right tab
Screws
Hood louver
REMOVAL OF OVEN FROM WALL (Two persons recommended to remove the oven)
5. While supporting the front of the oven, pull down the two
(2) mounting levers and release the oven from the unit
mounting plate.
6. Pull the power cord out of the wall cabinet and remove
the oven.
7. The oven is now free and can be placed on the work
surface selected for servicing the oven.
8. Installation is the reverse of this procedure.
1. Disconnect the power supply cord, and uncoil the power
supply cord.
2. To discharge the high voltage capacitor, wait for 60 seconds.
3. If the exhaust damper assembly is installed, remove the
one (1) screw holding the exhaust damper assembly to
the rear stay, and remove the exhaust damper assembly
by sliding it backward.
4. Remove the two (2) screws holding the oven (outer case
cabinet) to the top cabinet.
OUTER CASE REMOVAL
power supply cord together with the outer case.
8. Nip the cord bushing with bushing pliers and release it
from the outer case cabinet.
9. Remove the cord bushing and the power supply cord
from the outer case cabinet.
10.Now, the power supply cord or the outer case cabinet is
free.
CAUTION: 1. DISCONNECT OVEN FROM POWER
SUPPLY BEFORE REMOVING OUTER
CASE.
2. DISCHARGE THE HIGH VOLTAGE
CAPACITOR BEFORE TOUCHING ANY
OVEN COMPONENTS OR WIRING.
Remove the oven from the wall, referring to "REMOVAL OF
OVEN FROM WALL" and proceed as follows;
1. Disconnect the power supply cord.
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60 seconds.
4. Remove five (5) screws holding the rear stay to the outer
case cabinet, hood fan motor or the oven, and remove it.
5. Remove the six (6) screws from the rear of the outer case
cabinet and one (1) screw at front.
6. Slide the outer case cabinet back about 1 inch (3 cm) to
free it from retaining clips on the cavity face plate.
7. Disconnect the three (3) pin connector of the power
supply cord from the wiring harness and remove the
HOOD FAN MOTOR REMOVAL
from the main wire harness located at the right edge of
the oven cavity top plate and release the snap band from
the hood duct.
5. Remove the hood fan motor from the oven cavity top
plate by lifting it up.
6. Now, the hood fan motor is free.
1. Disconnect the power supply cord and remove the oven
from wall and remove outer case. (Refer to procedure of
"Removal of Oven from Wall" and "Outer case Removal")
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60 seconds.
4. Disconnect the 6-pin connector of the hood fan motor
MAGNETRON REMOVAL
1. Disconnect the power supply cord , remove the oven
from wall and remove outer case (Refer to procedure of
"Removal of Oven from Wall" and "Outer case Removal".)
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60 seconds.
4. Remove the seven (7) screws holding the hood intake
duct R to the oven cavity top plate, the oven cavity front
flange, the fan duct and magnetron duct. And remove the
hood intake duct R.
5. Disconnect the high voltage wire from the magnetron.
6. Release the two (2) tabs of the fan duct from the base plate R.
7. Remove the magnetron duct from the oven cavity, by
releasing the tab of the magnetron duct from the base
plate R.
8. Remove the grease filter (right side one) from the base cover.
9. Carefully remove four (4) mounting screws holding the
magnetron to waveguide. When removing the screws
hold the magnetron to prevent it from falling.
10.Remove the magnetron from the unit with care so the
magnetron tube should not be hit by any metal object
around the tube.
CAUTION: WHEN REPLACING THE MAGNETRON, BE
SURE THE R.F. GASKET IS IN PLACE AND
MOUNTING SCREWS ARE TIGHTENED SECURELY.
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HOOD FAN THERMAL CUT-OUT REMOVAL
1. Disconnect the power supply cord and remove the oven
from wall and remove outer case. (Refer to procedure of
"Removal of Oven from Wall" and "Outer case Removal")
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Remove the seven (7) screws holding the hood intake
duct R to the oven cavity top plate, the oven cavity front
5.
6.
7.
8.
flange, the fan duct and base plate R. And remove the
hood intake duct R.
Disconnect the wire leads from the hood fan thermal
cut-out.
Remove one (1) screw holding the thermal cut-out to the
flange of base plate R.
Remove the hood fan thermal cut-out from the base plate R.
Now, the hood fan thermal cut-out is free.
OVEN THERMAL CUT-OUT REMOVAL
1. Disconnect the power supply cord and remove the oven
from wall and remove outer case. (Refer to procedure of
"Removal of Oven from Wall" and "Outer case Removal")
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Disconnect the wire leads from the oven thermal cut-out.
5. Remove the oven thermal cut-out from the holder at
the oven cavity top plate.
6. Now, the oven thermal cut-out is free.
INVERTER UNIT AND FAN MOTOR REPLACEMENT
Reinstallation
1. Install the fan motor to the fan duct with the two (2)
screws.
2. Install the fan blade to the fan motor shaft. Refer to
“METHOD FOR INSTALLING FAN BLADE”.
3. Now, the fan motor should be installed.
4. Install the inverter unit to the fan duct with the two (2)
screws XOTSD40P12000 (4mm x 12mm).
5. Ground the inverter unit to the fan duct with the one (1)
screw XHTSD40P08RV0 (4mm x 8mm with a washer).
6. Install the fan duct (assembly) to the oven cavity top
plate with the one (1) screw.
7. Install the hood duct R to the oven cavity top plate with
the one (1) screw.
8. Reinstall the two connectors of the main wire harness
into the holes in the oven cavity top plate.
9. Reconnect all wire leads and connectors to the inverter
unit, fan motor, magnetron, fuse holder and fan duct,
referring to the pictorial diagram.
10.Reconnect the connectors between the main wire harness
and the oven lamp harness, referring to the pictorial
diagram.
11.Reconnect the connector of the hood fan motor to the
main wire harness, referring to the pictorial diagram.
12.Reinstall the wire leads to the hole of the fun duct.
13.Reinstall the hood intake duct R to the oven cavity top
plate, oven cavity front flange, fun duct, base plate R and
magnetron duct with the seven (7) screws.
14.Refer to the procedures of “OUTER CASE REMOVAL”.
And reverse their procedures. And reinstall the outer
case cabinet.
Removal
1. Disconnect the power supply cord.
2. Remove the oven from the wall, referring to “REMOVAL
OF OVEN FROM WALL”.
3. Remove the outer case cabinet, referring to “OUTER
CASE REMOVAL”.
4. Remove the seven (7) screws holding the hood intake
duct R to the oven cavity top plate, oven cavity front
flange, fan duct, base plate R and magnetron duct.
5. Remove the hood intake duct R.
6. Disconnect the main wire harness and the stop/pwm
wire harness from the inverter unit.
7. Disconnect the high voltage wire from the magnetron.
8. Disconnect the wire leads from the fan motor.
9. Disconnect the green wire (grounding wire) from the fan
duct.
10.Disconnect the connector between the main wire harness
and the hood fan motor.
11.Release the two (2) connectors of the main wire harness
from the oven cavity top plate.
12.Disconnect the main wire harness from the oven lamp
harness.
13.Disconnect the wire leads from the fuse holder.
14.Remove the one (1) screw holding the hood duct R to the
oven cavity top plate.
15.Remove the hood duct R from the oven cavity top plate.
16.Remove the one (1) screw holding the fan duct to the
oven cavity top plate.
17.Remove the fan duct with the inverter unit and the fan
motor from the oven.
18.Remove the three (3) screws holding the inverter unit to
the fan duct.
19.Disconnect the high voltage wire from the inverter unit.
20.Now, the inverter unit is free.
21.Remove the fan blade from the fan motor shaft. Refer to
“METHOD FOR REMOVING FAN BLADE”.
22.Remove the two (2) screws holding the fan motor to the
fan duct.
23.Now, the fan motor is free.
METHOD FOR REMOVING FAN BALDE
1. Hold the edge of the rotor of the fan motor by using a pair
of groove joint pliers.
CAUTION:
* Make sure that any pieces do not enter the gap
between the rotor and the stator of the fan motor
because the rotor is easily shaven by pliers and
32
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PMOR3021R
metal pieces may be produced.
Do not touch the pliers to the coil of the fan motor
because the coil may be cut or damaged.
* Do not disfigure the bracket by touching with the
pliers.
2. Remove the fan blade from the shaft of the fan motor by
pulling and rotating the fan blade with your hand.
3. Now, the fan blade will be free.
CAUTION:
* Do not reuse the removed fan blade because the
hole (for shaft) may be larger than normal.
ı
METHOD FOR INSTALLING FAN BALDE
1. Hold the center of the bracket which supports the shaft
of the fan motor on the flat table.
2. Install the fan blade to the shaft of fan motor by pushing
the fan blade with a small, light weight, ball peen hammer
or rubber mallet.
CAUTION:
* Do not hit the fan blade with excesive force when
installing because the bracket may be disfigured.
* Make sure that the fan blade rotates smooth after
installation.
* Make sure that the axis of the shaft is not slanted.
*
Coil
Groove joint pliers
Shaft
Axis
Stator
Gap
Bracket
Shaft
These are the positions
that should be pinched
with pliers.
Stator
Rotor
Rear View
Table
Center of
bracket
Rotor
Side View
STIRRER
MOTORS
REPLACEMENT
the motor mounting angle.
10.Now, the stirrer motor (right one) is free.
Removal
1. Disconnect the power supply cord.
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Remove the five (5) screws holding the bottom sash to
the base cover.
5. Remove the three (3) screws holding the base cover to
the oven cavity front face plate.
6. Open the base cover.
STIRRER MOTOR (LEFT ONE)
7. Disconnect the wire leads from the stirrer motor (left
one).
8. Remove the two (2) screws holding the stirrer motor to
the oven cavity.
9. Now, the stirrer motor (left one) is free.
STIRRER MOTOR (RIGHT ONE)
7. Disconnect the wire leads from the stirrer motor (right
one).
8. Remove the two (2) screws holding the motor mounting
angle to the oven cavity.
9. Remove the two (2) screws holding the stirrer motor to
Reinstallation
1. Insert a putty knife into the gap between the table tray
assembly and the oven cavity front plate. And remove
the table tray assembly from the oven cavity.
2. Install the stirrer motor (left one) to the oven cavity with
the two (2) screws.
3. Reconnect the wire lead to the stirrer motor (left one),
referring to the pictorial diagram.
4. Make sure that the stirrer motor gear, stirrer shaft
assembly and shield spring are installed to the motor
mounting angle.
5. Install the stirrer motor (right one) to the motor mounting
angle with the two (2) screws.
6. Install the motor mounting angle to the oven cavity with
the two (2) screws.
7. Reconnect the wire leads to the stirrer motor (right one),
referring to the pictorial diagram.
8. Reinstall the two (2) stirrer fans to the two (2) stirrer
shafts.
9. Reinstall the table tray assembly to the oven cavity.
STIRRER FAN ASSEMBLY INSTALLATION
UPSIDE
1. Make sure that the stirrer fan faces upside, as shown in
the following figure. The upside of the stirrer fan is
engraved with the part number.
2. Install the three stirrer spacers to the stirrer fan, as shown
in the following figure.
3. Install the stirrer fan to the stirrer shaft.
Parts number
B014
UPSIDE
Stirrer fan
Stirrer spacer
Stirrer fan assembly
33
PMOR3021S
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PMOR3021R
HOOD LAMP SOCKETS REMOVAL
6.
7.
8.
9.
Open the base cover.
Screw the hood lamp off from the lamp socket.
Disconnect the wire leads from the lamp socket.
Push the tab holding the lamp socket to the hood lamp
mount.
10.Remove the lamp socket from the hood lamp mount.
11. Now, the lamp socket is free.
1.
2.
3.
4.
Disconnect the power supply cord.
Open the door and block it open.
To discharge the high voltage capacitor, wait for 60 seconds.
Remove the five (5) screws holding the bottom sush to
the base cover.
5. Remove the three (3) screws holding the base cover to
the oven cavity front face plate.
OVEN LAMP AND LAMP SOCKET REMOVAL
1. Disconnect the power supply cord and remove the oven
from wall and remove outer case. (Refer to procedure of
"Removal of Oven from Wall" and "Outer case Removal")
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Remove one (1) screw holding the hood duct R to the
oven cavity top plate.
5. Release the hood duct R from the oven cavity top plate
by lifting it up.
6. Disconnect the wire leads from the lamp socket.
7. Remove the oven lamp angle from the hood duct R by
pushing the two (2) tabs holding the oven lamp angle..
8. Screw the oven lamp off from the lamp socket.
9. Now, the oven lamp is free.
10.Remove the lamp socket from the oven lamp angle by
pushing the tab holding the lamp socket.
11.Now, the oven lamp socket is free.
POSITIVE LOCK® CONNECTOR (NO-CASE TYPE) REMOVAL
Terminal
1. Disconnect the power supply cord and remove the oven
from wall and remove outer case. (Refer to procedure of
"Removal of Oven from Wall" and "Outer case Removal")
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Push the lever of positive lock® connector.
5. Pull down on the positive lock® connector.
Positive lock®
connector
1
Push
Lever
2
CAUTION: WHEN CONNECTING THE POSITIVE LOCK®
CONNECTORS TO THE TERMINALS, INSTALL THE POSITIVE LOCK® SO THAT THE
LEVER FACES YOU.
Pull down
Positive lock® connector
CONTROL PANEL ASSEMBLY, CONTROL UNIT AND KEY UNIT REMOVAL
1.
2.
3.
4.
Disconnect the power supply cord.
Open the door and block it open.
To discharge the high voltage capacitor, wait for 60 seconds.
Remove three (3) screws holding the hood louver to
oven cavity front face plate.
5. Remove the hood louver from the oven by pushing the
right and left tabs of the hood louver. (Refer to procedure
of "HOOD LOUVER REMOVAL")
6. Remove one (1) screw holding the control panel to the
oven cavity front face plate.
7. Release the control panel from the oven cavity front face
plate by lifting it up.
8. Disconnect the wire leads from the relay.
9. Disconnect all connectors from the control unit.
10. Remove the control panel assembly from the oven.
11.Now, the control panel assembly is free.
12.Disconnect the connector CN-G from the control unit.
13.Remove three (3) screws holding the control unit to the
key fixing angle.
14.Release the two (2) tabs holding the control unit to the
key fixing plate.
15.Now, the control unit is free.
16.Remove the one (1) screw holding the key fixing angle to
the control panel.
17.Release the seven (7) tabs holding the key fixing angle
to the control panel.
18.Remove the key fixing angle from the control panel.
19.Remove the key unit from the key fixing angle.
20.Now, the key unit is free
NOTES FOR KEY UNIT REPLACEMENT
1. Do not reuse the torn key unit because the performance
of the adhesive becomes weak.
2. Before attaching a new key unit, wipe off remaining
adhesive on the key fixing angle surfaces completely
with a soft cloth soaked in alcohol.
3. When attaching the key unit to the key fixing angle,
adjust the upper edge and right edge of the key unit to the
correct position of key fixing angle.
4. Stick the key unit firmly to the key fixing angle by rubbing
with soft cloth not to scratch.
34
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PMOR3021R
HUMIDITY SENSOR REMOVAL
1. Disconnect the power supply cord, remove the oven
from wall, and remove outer case. (Refer to procedure of
"REMOVAL OF OVEN FROM WALL" AND "OUTER
CASE REMOVAL".) And proceed as follows.
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Remove seven (7) screws holding the hood intake duct
R to the oven cavity top plate, the oven cavity front
flange, fan duct, base plate R, and magnetron duct. And
remove the hood intake duct R.
5. Disconnect the connector CN-F of humidity sensor from
the control unit.
6. Remove the two (2) screws and one (1) washer holding
the humidity sensor to the hood duct L.
7. Release the wire lead of humidity sensor from the holes
of the hood ducts L and R.
8. Now, the humidity sensor is free.
NOTE: When the humidity sensor is reinstalled, the wire tie
of the humidity sensor should be positioned through
the hole of the oven cavity top plate (right).
Sensor ground wire
Humidity sensor
Screws
Hole
Screw
Wire lead of humidity sensor
Hole
Hood duct L
Hood duct R
Hole
Wire tie
This illustration is under the condition which hood intake
duct R is removed
NOISE FILTER REMOVAL
4. Disconnect the wire leads from the terminals of the noise
filter .
5. Remove one (1) screw mounted into the noise filter and
chassis support.
6. Now the noise filter is free
1. Disconnect the power supply cord and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
TABLE TRAY ASSEMBLY
Removal
1. Open the door and block it open.
2. Insert a putty knife into the gap between the table tray
assembly and the oven cavity front plate. And lift up the
front edge of the table tray assembly.
3. Remove the table tray assembly from the oven cavity.
4. Now, the table tray assembly is free.
faces front. And place the table tray assembly into the
oven cavity.
5. At first, insert the front edge of the table tray assembly
into the oven cavity. And then push the rear edge of the
table tray assembly.
Table tray assembly
UPSIDE
FRO
Flat
NT
SID
E
Table tray assembly
Flat
Oven cavity
Front edge
Rear edge
Putty knife
Push
Oven cavity
Table Tray assembly removal
Reinstallation
1. Remove the two (2) stirrer fans.
2. Clean the oven cavity bottom plate and /or under the
antenna plate assembly by a vacuum cleaner.
3. Reinstall the two (2) stirrer fans to the stirrer shafts.
4. Make sure that the flat edge of the table tray assembly
Front edge
Table tray assembly
Table Tray assembly installation
35
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PMOR3021R
STOP SWITCH, PRIMARY INTERLOCK SWITCH, SECONDARY INTERLOCK SWITCH AND
MONITOR SWITCH REMOVAL
1. Disconnect the power supply cord and remove the oven
from wall and remove outer case. (Refer to procedure of
"Removal of Oven from Wall" and "Outer case Removal")
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Remove the seven (7) screws holding the hood intake
duct R to the oven cavity top plate, the oven cavity front
flange, fan duct, base plate R and magnetron duct. And
remove the hood intake duct R.
5. Remove the control panel assembly, referring to the
procedure of "CONTROL PANEL ASSEMBLY ,
CONTROL UNIT AND KEY UNIT REMOVAL".
6. Remove the two (2) screws holding the latch hook to the
oven cavity front flange.
7. Remove the latch hook from the oven cavity front flange.
8. Disconnect the wire leads of each switch.
9. Remove each switch from the latch hook by pushing the
one (1) stopper tab holding each switch.
10.Now, each switch is free.
Re-install
1. Re-install each switch in its place. The secondary interlock
switch is in the lower position, stop switch is in the upper
position and the primary interlock switch is the upper
position under the stop switch. And the monitor switch is
in the middle position.
2. Re-connect wire leads to each switch. Refer to pictorial
diagram.
3. Secure the latch hook (with two (2) mounting screws) to
oven cavity front flange.
4. Make sure that the monitor switch is operating properly
and check continuity of the monitor circuit. Refer to
chapter "Test Procedure" and "Adjustment procedure".
STOP SWITCH, PRIMARY INTERLOCK SWITCH, SECONDARY INTERLOCK SWITCH AND
MONITOR SWITCH ADJUSTMENT
After adjustment, check the following.
1. In and out play of door remains less than 0.5mm when
in the latched position. First check upper position of latch
hook, pushing and pulling upper portion of door toward
the oven face. Then check lower portion of the latch
hook, pushing and pulling lower portion of the door
toward the oven face. Both results (play in the door)
should be less than 0.5mm.
2. The secondary interlock switch and primary interlock
switch interrupt the circuit before the door can be opened.
3. Monitor switch contacts close when door is opened.
4. Stop switch contacts open when door is opened.
5. Re-install outer case and check for microwave leakage
around door with an approved microwave survey meter.
(Refer to Microwave Measurement Procedure.)
1. Disconnect the power supply cord and remove the oven
from wall and remove outer case. (Refer to procedure of
"Removal of Oven from Wall" and "Outer case Removal")
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Remove the seven (7) screws holding the hood intake
duct R to the oven cavity top plate, the oven cavity front
flange, fan duct, base plate R and magnetron duct. And
remove the hood intake duct R.
5. Remove the control panel assembly, referring to the
procedure of "CONTROL PANEL ASSEMBLY ,
CONTROL UNIT AND KEY UNIT REMOVAL".
If the stop switch, primary interlock switch, secondary
interlock switch and monitor switch do not operate properly
due to a misadjustment, the following adjustment should be
made.
6. Loosen the two (2) screws holding latch hook to the oven
cavity front flange.
7. With door closed, adjust latch hook by moving it back and
forth, and up and down. In and out play of the door
allowed by the upper and lower position of the latch hook
should be less than 0.5mm. The vertical position of the
latch hook should be adjusted so that the secondary
interlock switch and primary interlock switch are activated
with the door closed. The horizontal position of the latch
hook should be adjusted so that the monitor switch and
stop switch are activated with the door closed.
8. Secure the screws with washers firmly.
9. Check all of the switches operation. If any switch has not
activated with the door closed, loosen screw and adjust
the latch hook position.
Latch heads
Latch hook
Stop switch
Primary
interlock switch
Door
Monitor switch
Secondary
interlock switch
Open lever
Figure C-1. Latch Switch Adjustments
36
PMOR3021S
PMOR3021B
PMOR3021R
DOOR REPLACEMENT
After any servicing, make sure of the following :
1. Door latch heads smoothly catch latch hook through
latch holes and that latch head goes through center of
latch hole.
2. Deviation of door alignment from horizontal line of cavity
face plate is to be less than 1.0mm.
3. Door is positioned with its face pressed toward cavity
face plate.
4. Re-install outer case and check for microwave leakage
around door with an approved microwave survey meter.
(Refer to Microwave Measurement Procedure.)
DOOR ASSEMBLY REMOVAL
1. Disconnect the power supply cord.
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Remove the three (3) screws holding the hood louver to
the oven cavity front face plate.
5. Remove the hood louver from the oven cavity by pushing
the right and left tabs of the hood louver. (Refer to the
procedure of "HOOD LOUVER REMOVAL".)
6. Insert a putty knife (thickness of about 0.5mm) into the
gap A between the door stopper and the choke cover as
shown in Figure C-3 to free engaging parts.
7. Lift up the door stopper.
8. Now, the door stopper is free from the door assembly.
9. Lift up the door assembly to release the upper and lower
door hinge pins from the upper and lower oven hinges.
10.Now, the door assembly is free.
Note: The door on a microwave oven is designed to
act as an electronic seal preventing the leakage
of microwave energy from oven cavity during
cook cycle. This function does not require that
door be air-tight, moisture (condensation)-tight
or light-tight. Therefore, occasional appearance
of moisture, light or sensing of gentle warm air
movement around oven door is not abnormal
and do not of themselves indicate a leakage of
microwave energy from oven cavity.
Note: When the individual parts are replaced, refer to
"Door Disassembly".
DOOR ASSEMBLY RE-INSTALL
1. On re-installing door, insert the lower oven hinge to lower
door hinge pin.
2. Insert the upper oven hinge to the upper door hinge pin.
3. Shut the door (close the contacts of interlock switches).
4. Make sure upper and lower oven hinges are inserted into
the upper an lower door hinge pins.
5. Make sure the door is parallel with oven face lines (left
and upper side lines) and door latch heads pass through
latch holes correctly.
6. Re-install the door stopper to the door assembly.
7. Re-install the hood louver to the oven cavity front face
plate with the three (3) screws.
Note: After any service to the door;
(A) Make sure that stop switch primary interlock switch,
secondary interlock switch and monitor switch are
operating properly. (Refer to chapter "Test
Procedures".)
(B) An approved microwave survey meter should be
used to assure compliance with proper microwave
radiation emission limitation standards.
Hood louver
Left tab
Upper door hinge pin
Screw
Right tab
Screw
Upper oven
hinge
RE-INSTALL
Screw
Lower
oven
hinge
Door assembly
Latch heads
Door stopper
Lower door
hinge pin
RE-INSTALL
Figure C-2. Door Replacement and adjustment
DOOR DISASSEMBLY
1. Disconnect the power supply cord.
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Remove the three (3) screws holding the hood louver to
the oven cavity front face plate.
5. Remove the hood louver from the oven cavity by pushing
the right and left tabs of the hood louver. (Refer to the
procedure of "HOOD LOUVER REMOVAL".)
6. Remove door assembly, referring to "DOOR
REPLACEMENT".
Replacement of door components are as follows:
7. Place door assembly on a soft cloth with latches facing
up.
Note: As the engaging part of choke cover and door frame
are provided at 16 places, do not force any particular
part.
CHOKE COVER
8. Insert a putty knife (thickness of about 0.5mm) into the
gap A between the choke cover and door stopper and
between the choke cover and the door frame as shown
Figure C-3 to free engaging parts.
37
PMOR3021S
PMOR3021B
PMOR3021R
9. Pry the choke cover by inserting a putty knife in order
shown in Figure C-3.
10.Now choke cover is free from door panel and door frame.
NOTE: When carrying out any repair to the door, do not
bend or warp the slit choke (tabs on the door
panel assembly) to prevent microwave leakage.
Door stopper
A
Choke cover
DOOR FRAME ASSEMBLY
11.Remove four (4) screws holding the door panel to the
door frame assembly.
12.Release the door panel from the door frame assembly.
NOTE: It is easier to release the engaging parts of the upper
or lower door hinge pin side at first.
13.Now, door frame assembly is free.
Putty knife
LATCH SPRING, LATCH HEAD AND DOOR PANEL
14.Release the latch spring from the tab of the latch head
and tab of the door frame.
15.Release the latch head from the door frame.
16.Now, the latch spring and latch head are free.
Door frame
Figure C-3. Door Disassembly
38
4
NOISE FILTER
BOARD
GRY
GRY
BLU
WHT
1
RY3
9
N.O.
T1.
CN-A
1
GRY
BLK
5
YLW
2
3
9
PPL
5 RED
6
7 ORG
8
4
RED
1
CN-A
3 WHT
2
CN-B
1 YLW
ORG
4
5
CN-C
3
2
1
1 YLW
2
CN-H
3 PPL
2 GRN
BLK
CN-E
1
BLU
COM.
N.O.
N.O.
COM.
ORG
BRN
BLK
GRN
BLK
N.O.
ORG
BLK
BLK
RED
MONITOR
SWITCH
COM.
COM.
SECONDARY
INTERLOCK
SWITCH
N.C.
BLU
ORG
PRIMATY
INTERLOCK SWITCH
STOP SWITCH
SENSOR GROUND WIRE
BLK
BLU
2
1
PPL
BLU
ORG
BLU
BLU
BRN
WHT
STIRRER MOTOR
YLW
3
WHT
PPL
HOOD FAN MOTOR
BLK
3 BLK
WHT 1 WHT
ORG 2 BRN
RED 3 RED
ORG 4 RED
WHT
2 WHT
BLU
GRN 1 GRN
HOOD LAMP
AND SOCKETS
INVERTER UNIT
AC3
M
FA
F
ORG
To GND
RED
HOOD FAN
THERMAL
CUT-OUT
WHT
YLW
FA
F
FAN MOTOR
WHT
Power Supply
cord 120V 60Hz
MAGNETRON
RED
HIGH VOLTAGE COMPONENTS
RED
CN-A
Base plate R plate
GRN
GRN
WHT
WHT
WHT
BRN
6
RED 5 RED
YLW 4 YLW
WHT 3 WHT
BLK 2 BLK
BLU
1 BLU
BLU
5
Figure S-1. Pictorial Diagram
STIRRER MOTOR
BRN
BRN
ORG
RED
OVEN LAMP
AND SOCKET
FUSE AND HOLDER
RED
RED
OVEN THERMAL CUT-OUT
RED
4
CN-B
3
3
CN-H
1
CONTROL UNIT
WHT
BLK
1
CN-G
CN-F CN-E
3 1
13
2 1
39
CN-C
3
RY-1
GRN
HUMIDITY SENSOR
to oven cavity top plate
CN-F
1 BLK
2 RED
3 WHT
RED
1
2
H
5
1
N
RY4
F
RY5
D
3
RY6
C
GRY
B
3
G
2
CN-A
1
1
E
RED
PMOR3021S
PMOR3021B
PMOR3021R
6
A
A
B
C
H
6
D
E
F
G
H
PMOR3021S
PMOR3021B
PMOR3021R
1
2
4
3
5
6
A
A
B
B
C
C
D
D
E
E
F
F
G
G
H
H
Figure S-2b. Power Unit Circuit
1
2
4
3
40
5
6
PMOR3021S
PMOR3021B
PMOR3021R
1
2
4
3
5
6
A
B
B
C
C
D
D
Figure S-3b. LSI Unit Circuit
A
E
E
F
F
G
G
H
H
1
2
4
3
41
5
6
PMOR3021S
PMOR3021B
PMOR3021R
1
2
4
3
5
6
A
A
B
B
C
C
D
D
E
E
F
F
G
G
H
H
Figure S-4. Printed Wiring Board
1
2
4
3
42
5
6