R - 370EK
R - 3 70 E S
SERVICE MANUAL
S4112R370EPS/
MICROWAVE OVEN
Popcorn
Baked
Fresh
Potatoes Vegetables
Reheat
Sensor
Ground Frozen
Meat Vegetables Chicken
Breast
Rice
Frozen
Entree
Rolls &
Muffins
MODELS
Compu
Defrost
Fish
Seafood Veverage Kitchen Timer
Clock
1
2
3
4
5
Power
Level
Custom
Help
6
7
8
9
0
STOP
Clear
Minute Plus
START
R-370EK
R-370ES
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 following parts may result in a severe,
possibly fatal, electrical shock. (High Voltage Capacitor, High
Voltage Power Transformer, Magnetron, High Voltage Rectifier Assembly, 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 ................................................................................................................................... 4
OPERATION .......................................................................................................................................................... 6
TROUBLESHOOTING GUIDE ............................................................................................................................ 10
TEST PROCEDURE ............................................................................................................................................ 12
TOUCH CONTROL PANEL ................................................................................................................................. 21
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE ................................................................ 26
PICTORIAL DIAGRAM ........................................................................................................................................ 33
POWER UNIT CIRCUIT ...................................................................................................................................... 34
CPU UNIT CIRCUIT ............................................................................................................................................ 35
PRINTED WIRING BOARD ................................................................................................................................. 36
PARTS LIST ........................................................................................................................................................ 37
PACKING AND ACCESSORIES ......................................................................................................................... 39
SHARP CORPORATION
This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
R-370EK
R- 370ES
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 SHARP ELECTRONICS
CORPORATION immediately @1-800-237-4277.
If the unit operates with the door open, service person should 1) tell the user not to operate the oven
and 2) contact SHARP ELECTRONICS CORPORATION and Food and Drug Administration's
Center for Devices and Radiological Health immediately.
Service personnel should inform SHARP ELECTRONICS CORPORATION 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.
R-370EK
R-370ES
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)
High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc..
Read the Service Manual carefully and follow all
instructions.
Don't Touch !
Danger High Voltage
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. Discharge high voltage capacitor.
4. Reconnect the leads to the primary of the power
transformer.
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
remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
, and then
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. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power
transformer.
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.
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 a microwave leakage test should be carried out.
1
R- 370EK
R- 37 0ES
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 relay and door sensing 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.
3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5˚C (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.
NOTE: After servicing, record data on service invoice and microwave leakage report.
2
R-370EK
R-370ES
SERVICE MANUAL
PRODUCT DESCRIPTION
MICROWAVE OVEN
R-370EK/ R-370ES
GENERAL INFORMATION
FOREWORD
This Manual has been prepared to provide Sharp Electronics Corp.
Service Personnel with Operation and Service Information for the
SHARP MICROWAVE OVEN, R-370EK, R-370ES.
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.
Check the interlock switches and the door seal carefully. Special
attention should be given to avoid electrical shock and microwave
radiation hazard.
OPERATION
TROUBLESHOOTING GUIDE AND
TEST PROCEDURE
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.
Servicing and repair work must be carried out only by trained service
personnel.
COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
WIRING DIAGRAM
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;
High Voltage Capacitor, Power Transformer, Magnetron, High
Voltage Rectifier Assembly, High Voltage Harness;
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 wrap 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.
SHARP ELECTRONICS CORPORATION
SHARP PLAZA, MAHWAH,
NEW JERSEY 07430-2135
3
PARTS LIST
R- 370EK
R- 37 0ES
SPECIFICATION
ITEM
DESCRIPTION
Power Requirements
120 Volts / 13.5 Amperes
60 Hertz
Single phase, 3 wire grounded
Power Output
1000 watts (IEC TEST PROCEDURE)
Operating frequency of 2450MHz
Case Dimensions
Width 17-1/4"
Height 13-3/8"
Depth 18-3/8"
Cooking Cavity Dimensions
Width 13-3/4"
Height 7-1/4"
Depth 16-1/2"
1.4 Cubic Feet
Control Complement
Touch Control System
Clock ( 1:00 - 12:59 )
Timer (0 - 99 min. 99 seconds)
Microwave Power for Variable Cooking
Repetition Rate;
HIGH ................................................ 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 COOKING pads , INSTANT ACTION pads
COMPU DEFROST pads, Number selection pads
CUSTOM HELP PAD, POWER LEVEL pad,
KITCHEN TIMER/CLOCK pad
STOP/CLEAR pad, MINUTE PLUS /START pad
Oven Cavity Light
Yes
Safety Standard
UL Listed
FCC Authorized
DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J
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 electrical requirements are a 120 volt 60 Hz, AC only,
15 or 20 amp. fused electrical supply. It is recommended that a separate circuit serving only this appliance be provided. When
installing this appliance, observe all applicable codes and ordinances.
A short power-supply cord is provided to reduce risks of becoming entangled in or tripping over a longer cord.
Where a two-pronged wall-receptacle is encountered, it is the personal responsibility and obligation of the customer to
4
R-370EK
R-370ES
contact a qualified electrician and have it replaced with a properly
grounded three-pronged wall receptacle or have a grounding adapter
properly grounded and polarized. If the extension cord must be used, it
should be a 3-wire, 15 amp. or higher rated cord. Do not drape over a
countertop or table where it can be pulled on by children or tripped over
accidentally.
CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE THE ROUND GROUNDING PRONG FROM THIS
PLUG.
Grounded
Receptacle Box
3-Pronged Plug
Grounding Pin
3-Pronged Receptacle
OVEN DIAGRAM
1. Door handle
Pull to open door.
2. Auto-Touch control panel
3. Display: 99 minutes, 99 seconds
4. Oven door with see-through window
5. Safety door latch
The oven will not operate unless the door is
securely closed.
6. Door hinges
7. Door seals and sealing surface
2
8. Turntable motor shaft
9. Removable turntable support
Carefully place the turntable support in the center
of the oven floor.
10. Removable turntable
Place the turntable on the turntable support
cecurely. The turntable will rotate clockwise or
counterclockwise. Only remove for cleaning.
11. Ventilation openings (Rear)
12. Oven light
It will light when oven is operating or door is
opened.
13. Wave guide cover: DO NOT REMOVE.
7
11
3
8
5
1
12
13
;;
;;
;;
;;
6
4
10
9
TOUCH CONTROL PANEL
Popcorn
Baked
Fresh
Potatoes Vegetables
Reheat
Sensor
Ground Frozen Chicken
Meat Vegetables Breast
Rice
Frozen
Entree
Rolls &
Muffins
Compu
Defrost
Fish Beverage Kitchen Timer
Seafood
Clock
COOK SENSOR LBS
DEF HELP
1
2
3
4
5
Power
Level
Custom
Help
6
7
8
9
0
STOP
Clear
Minute Plus
START
NOTE:
The directed features 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.
5
R- 370EK
R- 37 0ES
OPERATION
DESCRIPTION OF OPERATING SEQUENCE
The following is a description of component functions during
oven operation.
so that it will function in the following sequence.
(1) When the door opens from the closed position, the
secondary interlock relay (RY2) and primary interlock
switch open their contacts. And contacts of the relay
(RY1) remains closed. Then the monitor switch contacts
close.
(2) When the door is closed from the open position, the
monitor switch contacts open first. Then the contacts of
the primary interlock switch and door sensing switch
close. And contacts of the relay (RY1) open.
If the primary interlock switch and secondary interlock relay
(RY2) fail with the contacts closed when the door is opened,
the closing of the monitor switch contacts will form a short
circuit through the monitor fuse, primary interlock switch,
relay (RY1) and secondary interlock relay (RY2), causing
the monitor fuse to blow.
OFF CONDITION
Closing the door activates the door sensing switch and
primary 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 "SHARP SIMPLY THE BEST
PRESS CLEAR AND PRESS CLOCK".To set any
program or set the clock, you must first touch the STOP/
CLEAR pad. The display will clear, and " : " will appear.
COOKING CONDITION
Program desired cooking time by touching the NUMBER
pads. Program the power level by touching the POWER
LEVEL pad.
When the START pad is touched, the following operations
occur:
POWER LEVEL P-0 TO P-90 COOKING
When Variable Cooking Power is programmed, the 120
volts A.C. is supplied to the power transformer intermittently
through the contacts of relay (RY2) which is operated by the
control unit within a 32 second time base. Microwave power
operation is as follows:
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
RY-1
RY-2
VARI-MODE
100%
CONNECTED COMPONENTS
oven lamp/turntable motor/fan motor
power transformer
2. 120 volts A.C. is supplied to the primary winding of the
power transformer and is converted to about 3.4 volts
A.C. output on the filament winding, and approximately
2300 volts A.C. on the high voltage winding.
3. The filament winding voltage heats the magnetron
filament and the H.V. winding voltage is sent to a voltage
doubler circuit.
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 power
transformer, 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, door sensing switch, primary interlock
switch, relay (RY1) and secondary interlock relay (RY2)
are activated with the following results. The circuits to the
turntable motor, the cooling fan motors, and the high
voltage components are de-energized, the oven lamp
remains on, and the digital read-out displays the time still
remaining in the cook cycle when the door was opened.
7. The monitor switch electrically monitors the operation of
the primary interlock switch and secondary interlock
relay (RY2) and is mechanically associated with the door
DISPLAY
ON TIME
OFF TIME
HIGH
32 sec.
0 sec.
approx. 90% power
P-90
30 sec.
2 sec.
approx. 80% power
P-80
26 sec.
6 sec.
approx. 70% power
P-70
24 sec.
8 sec.
approx. 60% power
P-60
22 sec.
10 sec.
approx. 50% power
P-50
18 sec.
14 sec.
approx. 40% power
P-40
16 sec.
16 sec.
approx. 30% power
P-30
12 sec.
20 sec.
approx. 20% power
P-20
8 sec.
24 sec.
approx. 10% power
P-10
6 sec.
26 sec.
P-0
0 sec.
32 sec.
0% power
Note:
The ON/OFF time ratio does not correspond with
the percentage of microwave power, because
approx. 2 seconds are needed for heating of the
magnetron filament.
POWER OUTPUT REDUCTION
If the oven is set for more than 30 minutes at 80, 90 or 100%
power level, after the first 30 minutes the power level will
automatically adjust itself to 70% power to avoid overcooking.
SENSOR COOKING CONDITION
Using the SENSOR 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
6
R-370EK
R-370ES
is cooked, water vapor is developed. The sensor “senses”
the vapor and its resistance increases gradually. When the
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 inputted into the LSI.
An example of how sensor works: (POTATOES)
3. Sensor detects moisture and humidity and calculates
cooking time and variable power.
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 motors are turned on,
but the power transformer is not turned on.
3. After about 16 seconds, the cook relay (RY-2) is
energized. The power transformer is turned on,
microwave energy is produced and first stage is started.
The 16 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 and cook relay are de-energized and
the power transformer, 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.
1. Potates at room temperature. Vapor is emitted very
slowly.
MI
CRO
WA
VE
2. Heat Potates. Moisture and humidity is emitted rapidly.
You can smell the aroma as it cooks.
AH SENSOR
MIC
RO
WA
VE
7
R- 370EK
R- 37 0ES
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. CLOCK APPEARS ON DISPLAY
NOTE: " " indicates components with potential above 250V.
AH SENSOR
MONITOR
FUSE 20A
OVEN THERMAL
CUT-OUT
MG. THERMAL CUT-OUT
POWER
TRANSFORMER
N.O.
F3
F2
F1
SECONDARY
INTERLOCK
RELAY (RY2)
CAPACITOR
0.94µF
AC 2200V
COM.
GRN
B2
120V AC
60 Hz
MONITOR
SWITCH
CONTROL UNIT
B1
DOOR
SENSING
SWITCH
OL
OVEN LAMP
RELAY (RY1)
N.O.
OVEN
LAMP
TTM
PRIMARY
INTERLOCK
SWITCH
FM
TURNTABLE
MOTOR
FAN
MOTOR
RECTIFIER
FM
MAGNETRON
FAN
MOTOR
COM.
Figure O-1. Oven Schematic-Off Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED
2. COOKING TIME PROGRAMMED
3. VARIABLE COOKING CONTROL "P-HI" (100%)
4. "START" PAD TOUCHED
NOTE: " " indicates components with potential above 250V.
AH SENSOR
MONITOR
FUSE 20A
OVEN THERMAL
CUT-OUT
MG. THERMAL CUT-OUT
POWER
TRANSFORMER
N.O.
F3
F2
F1
SECONDARY
INTERLOCK
RELAY (RY2)
CAPACITOR
0.94µF
AC 2200V
COM.
GRN
120V AC
60 Hz
B2
B1
MONITOR
SWITCH
CONTROL UNIT
DOOR
SENSING
SWITCH
OL
OVEN LAMP
RELAY (RY1)
N.O.
OVEN
LAMP
TTM
PRIMARY
INTERLOCK
SWITCH
TURNTABLE
MOTOR
FM
FAN
MOTOR
RECTIFIER
FM
MAGNETRON
FAN
MOTOR
COM.
Figure O-2. Oven Schematic-Cooking Condition
8
R-370EK
R-370ES
DESCRIPTION AND FUNCTION OF COMPONENTS
DOOR OPEN MECHANISM
RELAY (RY1), PRIMARY INTERLOCK
SWITCH AND MONITOR SWITCH FOR
PROPER OPERATION. (REFER TO CHAPTER "TEST PROCEDURE").
NOTE: MONITOR FUSE AND MONITOR SWITCH ARE
REPLACED AS AN ASSEMBLY.
The door is opened by pulling the door. Refer to the Figure
D-1.
Door
Latch
Heads
Latch Hook
TURNTABLE MOTOR
Door Sensing
Switch
The turntable motor rotates the turntable located on the
bottom of the oven cavity, so that the foods on the turntable
cook evenly during cooking. The turntable may turn in either
direction.
Monitor Switch
COOLING FAN MOTOR
Primary
Interlock Switch
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.
Figure D-1. Door Open Mechanism
DOOR SENSING AND PRIMARY INTERLOCK
SWITCHES
The primary interlock switch is mounted in the lower position
of the latch hook and the door sensing switch in the
secondary interlock system is mounted 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 power to all high voltage components. A cook cycle
cannot take place until the door is firmly closed thereby
activating both interlock switches. The secondary interlock
system consists of the door sensing switch and secondary
interlock relay located on the control circuit board.
MONITOR FUSE
1. The monitor fuse blows when the contacts (COM-NO) of
the secondary interlock relay (RY2) and primary interlock
switch remain closed with the oven door open and when
the monitor switch closes.
2. If the wire harness or electrical components are shortcircuited, this monitor fuse blows to prevent an electric
shock or fire hazard.
MONITOR SWITCH
OVEN THERMAL CUT-OUT
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 secondary interlock relay (RY2) and primary interlock switch fail to
open when the door is opened.
The thermal cut-out, located on the top of the oven cavity, is
designed to prevent damage to the oven by fire. If the food
load is overcooked, by either error in cook time or defect in
the control unit, the thermal cut-out will open.
Under normal operation, the oven thermal cut-out remains
closed. However, when abnormally high temperatures are
reached within the oven cavity, the oven thermal cut-out will
open at 257˚F(125˚C), causing the oven to shut down.
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 secondary interlock relay (RY2)
and primary interlock switch are in the OFF condition
(contacts open) due to their being normally open contact
switches.
2. As the door goes to a closed position, the monitor switch
contacts are first opened and then the door sensing
switch and the primary interlock switch contacts close.
(On opening the door, each of these switches operate
inversely.)
3. If the door is opened, and the secondary interlock relay
(RY2) and primary interlock switch contacts fail to open,
the monitor fuse blows simultaneously with closing of the
monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN MONITOR
FUSE TEST THE DOOR SENSING SWITCH,
SECONDARY INTERLOCK RELAY (RY2),
MAGNETRON THERMAL CUT-OUT
The thermal cut-out located near the magnetron is designed
to prevent damage to the magnetron if an over heated
condition develops in the tube due to cooling fan failure,
obstructed air guide, dirty or blocked air intake, etc.
Under normal operation, the thermal cut-out remains closed.
However, when abnormally high temperatures are reached
within the magnetron, the thermal cut-out will open at
257˚F(125˚C) causing the oven to shut down.
9
R- 370EK
R- 37 0ES
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)
secondary interlock relay (RY2), door sensing switch and primary interlock switch before replacing the
monitor fuse. If the monitor fuse is replaced, the monitor switch must also be replaced. Use part FFSBA023WRK0 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. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power transformer.
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. Discharge high voltage capacitor.
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.
10
R-370EK
R-370ES
CK = Check / RE = Replace
Monitor fuse blows when power cord
is plugged into wall receptacle.
OFF
CONDITION
Any letters or indicators do not appear in display when power cord is
first plugged into wall outlet.
Display does not operate properly
when STOP/CLEAR key is touched.
(Buzzer should sound and ":" or time
of day should appear in display.)
Oven lamp does not light when door is
opened.
Oven lamp does not go out when door
is closed.
Oven lamp lights but fan motor and
turntable motor do not operate.
Oven does not go into cook cycle
when START pad is touched
COOKING
CONDITION
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).
Oven does not cook properly when
programmed for Cooking Power P-50
mode. (Operates properly on Cooking Power HIGH (100%) mode.)
Oven goes into COMPU DEFROST
but food is not defrosted well.
SENSOR
COOKING
CONDITION
AH sensor 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 16 sec. after starting.
11
AH SENSOR
FOIL PATTERN ON PWB.
COMPU DEFROST
KEY UNIT
K L M N
RELAY (RY1)
DIRTY OVEN CAVITY
LOW VOLTAGE
CONTROL UNIT
WRONG OPERATION
TURNTABLE MOTOR
COOLING FAN MOTOR
OVEN LAMP
MONITOR SWITCH
MONITOR FUSE
PRIMARY INTERLOCK SWITCH
SECONDARY INTERLOCK SYSTEM
HIGH VOLTAGE CAPACITOR
Home fuse or circuit breaker blows
when power cord is plugged into wall
receptacle.
THERMAL CUT-OUT
H.V. RECTIFIER ASSEMBLY
POWER TRANSFORMER
SHORT OR OPENED WIRING
PROBLEM
MAGNETRON
CONDITION
RE RE A B C D E F F G H RE RE CK I CK CK CK J
SHORT IN POWER CORD
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
TEST PROCEDURE
R- 370EK
R- 37 0ES
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.
Discharge the high voltage capacitor.
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: silicon rectifier, high voltage capacitor and power transformer. 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 P-HI(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 30.7
to 57.1˚F(17.1 to 31.7˚C) 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
POWER TRANSFORMER 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.
Discharge the high voltage capacitor.
Disconnect the primary input terminals and measure the resistance of the transformer with an
ohmmeter. Check for continuity of the coils with an ohmmeter. On the R x 1 scale, the resistance of
the primary coil should be less than 1 ohm and the resistance of the high voltage coil should be
approximately 85 ohms; the resistance of the filament coil should be less than 1 ohm.
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.
12
R-370EK
R-370ES
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
(HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO
MEASURE THE FILAMENT AND HIGH VOLTAGE.)
C
HIGH VOLTAGE RECTIFIER TEST
1.
2.
3.
4.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge the high voltage capacitor.
Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance
across the terminals and observe, reverse the leads to the rectifier terminals and observe meter
reading. If a short is indicated in both directions, or if an infinite resistance is read in both directions,
the rectifier is probably defective and should be replaced.
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: Be sure to use an ohmmeter that will supply a forward bias voltage of more than 6.3 volts.
D
HIGH VOLTAGE CAPACITOR 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.
Discharge the high voltage capacitor.
If the capacitor is open, no high voltage will be available to the magnetron. Disconnect input leads
and check for short or open between the terminals using an ohmmeter.
Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate
continuity for a short time and should indicate an open circuit once the capacitor is charged. If the
above is not the case, check the capacitor with an ohmmeter to see if it is shorted between either of
the terminals and case. If it is shorted, replace the capacitor.
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.
OVEN THERMAL CUT-OUT 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 the 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 257˚F(125˚C).
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.
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.
MAGNETRON THERMAL CUT-OUT TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60 seconds.
4. A continuity check across the thermal cut-out terminals should indicate a closed circuit unless the
temperature of the magnetron reaches approximately 257˚F(125˚C). An open thermal cut-out
indicates overheating of the magnetron. Check for restricted air flow to the magnetron, especially the
cooling fan air guide.
13
R- 370EK
R- 37 0ES
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
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.
F
PRIMARY INTERLOCK 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 the 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.
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.
SECONDARY INTERLOCK SYSTEM TEST
DOOR SENSING SWITCH
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60 seconds.
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 door sensing 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 door sensing switch contacts fail in the open position and the door is closed, the cooling
fan, turntable and oven light will be activated by RY1.
SECONDARY INTERLOCK RELAY (RY2)
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60 seconds.
4. Disconnect two (2) wire leads from the male tab terminals of the Secondary interlock relay. Check
the state of the relay contacts using a ohmmeter. The relay contacts should be open. If the relay
contacts are closed, replace the circuit board entirely or the relay itself.
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.
G
MONITOR SWITCH TEST
1.
2.
3.
4.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge the high voltage capacitor, wait for 60 seconds.
Before performing this test, make sure that the primary interlock switch and the secondary interlock
relay 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
14
R-370EK
R-370ES
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
5.
6.
7.
8.
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 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
WHT
functions.
RED
Screw Driver
Monitor Switch
Primary
Interlock Switch
H
Ohmmeter
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 the high voltage capacitor, wait for 60 seconds.
If the monitor fuse is blown when the door is opened, check the secondary interlock relay, primary
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 SECONDARY INTERLOCK RELAY, PRIMARY INTERLOCK SWITCH, DOOR SENSING 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-BA023WRK0, 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. 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.
I
CONTROL UNIT TEST
The control unit 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 control panel unit is divided into three units, CPU Unit, Key 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.
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 power transformer.
5) Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
1. Key Unit.
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.
15
R- 370EK
R- 37 0ES
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
If the Key unit is defective, replace the key unit.
2. Control Unit
The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the Key unit test (Procedure J) 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 and/or replacement is completed,
1) Disconnect the power supply cord, and then remove outer case.
2) To discharge the high voltage capacitor, wait for 60 seconds.
3) Re-install all removed parts.
4) Reconnect all leads removed from components during testing.
5) Re-install the outer case (cabinet).
6) Reconnect the power supply cord after the outer case is installed.
7) Run the oven and check all functions.
KEY UNIT TEST
1. Disconnect the power supply cord, and then remove outer case.
2. To discharge the high voltage capacitor, wait for 60 seconds.
3. 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 door sensing switch (stop switch) operates properly; that is the
contacts are closed when the door is closed and open when the door is open. If the door sensing
switch (stop switch) is good, disconnect the flat ribbon cable that connects the key unit to the control
unit and make sure the door sensing switch is closed (either close the door or short the door sensing
switch connecter). Use the Key unit matrix indicated on the control panel 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.
4. Reconnect all leads removed from components during testing.
5. Re-install the outer case (cabinet).
6. Reconnect the power supply cord after the outer case is installed.
7. Run the oven and check all functions.
G7
G11 G10 G 9 G 8
J
Frozen
Entrees
Rice
G6
G5
Rolls &
Fresh
Muffins Vegetables
Compu
Baked
Defrost Potatoes
G4
G3
G2
G1
1
2
4
8
3
5
Power
Level
Custom
Help
7
9
Minute Plus
START
6
0
STOP
Clear
Fish
Ground
Popcorn
Seafood Beverage Meat
Reheat
Chicken Kitchen Timer Frozen
Vegetables Sensor
Breast
Clock
16
R-370EK
R-370ES
TEST PROCEDURES
PROCEDURE
LETTER
K
COMPONENT TEST
RELAY TEST
1.
2.
3.
4.
5.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge the high voltage capacitor, wait for 60 seconds.
Disconnect the leads to the primary of the power transformer.
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.
7. Remove the outer case and check voltage between the normal open terminal of the relay RY1 and
the normal open terminal of the relay RY2 on the control unit with an A.C. voltmeter.
The meter should indicate 120 volts, if not check oven circuit.
RY1 and RY2 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
RY1
RY2
OPERATIONAL VOLTAGE
Approx. 24.0V D.C.
CONNECTED COMPONENTS
Oven lamp / Turntable motor / Cooling fan motor
Approx. 23.0V D.C.
Power transformer
8. Disconnect the power supply cord, and then remove outer case.
9. Open the door and block it open.
10.To discharge the high voltage capacitor. wait for 60 seconds.
11.Reconnect all leads removed from components during testing.
12.Re-install the outer case (cabinet).
13.Reconnect the power supply cord after the outer case is installed.
14.Run the oven and check all functions.
L
COMPU DEFROST TEST
WARNING : The oven should be fully assembled before following procedure.
(1) Place one cup of water in the center of the turntable tray in the oven cavity.
(2) Close the door, touch the " COMPU DEFROST " pad once.
(3) Touch " COMPU DEFROST " pad twice.
(4) Touch the Number pad " 5 " and then touch the " START " pad.
(5) The oven is in Compu Defrost cooking condition.
(6) The oven will operate as follows.
MENU
Steaks/Chops
0.5lb
1ST STAGE
LEVEL
TIME
60%
40sec.
2ND STAGE
LEVEL
TIME
40%
40sec.
(7) If improper operation is indicated, the control unit is probably defective and should be checked.
M
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, and then remove outer case.
2) Open the door and block it open.
3) To discharge the high voltage capacitor, wait for 60 seconds.
4) Follow the troubleshooting guide given below for repair.
17
R- 370EK
R- 37 0ES
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
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".
RY1
5) Make a visual inspection of the varistor. Check
1
2
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 212Ω ±
10%). If any abnormal condition is detected,
CN - A
replace the defective parts.
(J1)
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.
9) Run the oven and check all functions.
2. Follow the troubleshooting guide given below, if the indicator does not light up after above check and
repairs are finished.
1) Disconnect the power supply cord, and then remove outer case.
2) Open the door and block it open.
3) To discharge the high voltage capacitor, wait for 60 seconds.
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.
7) Follow the troubleshooting guide given below for repair.
VRS1
a
d
c
P
N
1
8)
9)
10)
11)
12)
13)
14)
OCCURRENCE
T1
RY2
STEPS
b
CAUSE OR CORRECTION
1
The rated AC voltage is not present between
the normal open terminal of the relay RY1 and Check supply voltage and oven power cord.
the normal open terminal of the relay RY2.
2
The rated AC voltage is present at primary
side of low voltage transformer.
Low voltage transformer or secondary circuit defective.
Check and repair.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
To discharge the high voltage capacitor, wait for 60 seconds.
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.
AH SENSOR TEST
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.
(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.
18
R-370EK
R-370ES
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
(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 KITCHEN 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 16 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 16 seconds, microwave energy is produced.
If ERROR is displayed or the oven does not turn off, replace the AH sensor or check the control unit, refer
to explanation below. If the oven stops after 5 minutes and ERROR is displayed, the AH sensor is normal.
Check other parts except the AH sensor.
TESTING METHOD FOR AH 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.
(2) Open the door and block it open.
(3) Discharge high voltage capacitor.
(4) Remove the AH sensor.
(5) Install the new AH 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.
(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 KITCHEN 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)
(2)
(3)
(4)
(5)
(6)
(7)
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor.
Disconnect the sensor connector that is mounted to control panel.
Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.
Disconnect the leads to the primary of the power transformer.
Ensure that these leads remain isolated from other components and oven chassis by using insulation
tape.
19
R- 370EK
R- 37 0ES
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
(8) After that procedure, re-connect the power supply cord.
(9) Check the sensor cook operation proceed as follows:
9-1. Touch the KITCHEN TIMER/CLOCK pad once, the POWER LEVEL pad twice, the START pad
once, the number pad 1 once and the number pad 4 once.
9-2. The control panel is in the sensor cooking operation.
9-3. After approximately 25 seconds, push plunger of select switch for more than 3 seconds. This
condition is same as judgement by AH 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 AH sensor is probably defective.
(10) Disconnect the power supply cord, and then remove outer case.
(11) Open the door and block it open.
(12) Discharge high voltage capacitor.
(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.
Plunger
R1, R2 : 22Ω ± 1% 1/2W
R3 : 4.3kΩ ± 5% 1/4W
R4 : 1MΩ ± 5% 1/4W
To connector (F)
on Control Unit.
1
F-1
F-2
NC
NO
COM
COM NO
2
3
R1
F-3
R2
CONNECTOR
R3
R4
Sensor Dummy Resistor Circuit
20
NC
R-370EK
R-370ES
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
In addition, the synchronizing signal is available in order
to compose a basic standard time in the clock circuit.
The control unit section consists of the following units.
(1) Key Unit
(2) Control Unit (The Control Unit consists of Power Unit and
CPU Unit).
The principal functions of these units and the signals communicated among them are explained below.
Symbol
Voltage
VC
-5V
Application
LSI(IC1)
4) Relay Circuit
A circuit to drive the magnetron, fan motor, turntable
motor and light the oven lamp.
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 and P26.
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 responsive to signals from the LSI to emit
audible sounds (key touch sound and completion sound).
6) Synchronizing Signal Circuit
The power source synchronizing signal is available in
order to compose a basic standard time in the clock
circuit.
It accompanies a very small error because it works on
commercial frequency.
Control Unit
Control unit consists of LSI, ACL circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit, synchronizing signal circuit, back light circuit and absolute humidity
sensor circuit.
7) Door Sensing Switch
A switch to “tell” the LSI if the door is open or closed.
1) ACL
This circuit generates a signal which resets the LSI to the
initial state when power is supplied.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD1- LD4).
2) Indicator Circuit
This circuit consists of 25 segments and 4 common
electrodes using a Liquid Crystal Display.
9) Absolute Humidity Sensor Circuit
This circuit detects moisture of the cooking food to allow
its automatic cooking.
3) Power Source Circuit
This circuit generates voltages necessary in the control
unit from the AC line voltage.
LSI(IXA102DR)
The I/O signal of the LSI(IXA102DR) is detailed in the following table.
Pin No.
Signal
I/O
Description
1-2
VL2-VL1
IN
Power source voltage input terminal.
Standard voltage for LCD.
3-6
AN7-AN4
IN
Terminal to change cooking constant 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.
7
AN3
OUT
8
AN2
IN
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).
21
R- 370EK
R- 37 0ES
Pin No.
Signal
I/O
Description
9
AN1
IN
AH sensor input.
This input is an analog input terminal from the AH sensor circuit, and connected to the
A/D converter built into the LSI.
10
AN0
IN
Used for initial balancing of the bridge circuit (absolute humidity sensor). This input is an
analog input terminal from the AH sensor circuit, and connected to the A/D converter built
into the LSI.
11-13
P57-P55
OUT
Used for initial balancing of the bridge circuit (absolute humidity sensor).
14
CNTR0
OUT
Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
0.1 sec.
H : GND
A
2.0 sec.
L : -5V
H : GND
B
L : -5V
15
P53
OUT
Used for initial balancing of the bridge circuit (absolute humidity sensor).
16
P52
OUT
Oven lamp, fan motor and turntable motor driving signal
16.7 msec.
To turn on and off shut off relay (RY1). The
square waveform voltage is delivered to the
RY1 driving circuit and RY2 control circuit.
H : GND
L : -5V
During cooking
17
P51
OUT
Used for initial balancing of the bridge circuit (absolute humidity sensor).
18
P50
OUT
Terminal not used.
19
P47
OUT
Magnetron high-voltage circuit driving signal.
OFF
H : GND
To turn on and off the cook relay (RY2). The
P-HI
ON
signals holds "L" level during microwave cookL : -5V
ing and "H" level while not cooking. In other
OFF
OFF
H : GND
cooking modes (variable cooking) the signal
24 sec.
P-70
8 sec.
turns to "H" level and "L" level in repetition
ON
L : -5V
according to the power level.
(ON and OFF times for other power level.)
20
P46
IN
Signal coming from touch key.
When either G11 line on key matrix is touched, a corresponding signal out of P20 - P26
will be input into P46. When no key is touched, the signal is held at "H" level.
21
P45
IN
Signal similar to P46.
When either G10 line on key matrix is touched, a corresponding signal will be input into P45.
22
P44
IN
Signal similar to P46.
When either G9 line on key matrix is touched, a corresponding signal will be input into P44.
23
P43
IN
Signal similar to P46.
When either G8 line on key matrix is touched, a corresponding signal will be input into P43.
24
INT0
IN
Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
H : GND
L : -5V
16.7 msec.
25
P41
OUT
Terminal not used.
26
P40
IN
Connected to GND through the pull-down resistor R100.
27
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied. Temporarily set
"L" level the moment power is applied, at this time the LSI is reset. Thereafter set at "H"
level.
28-29
P71-P70
OUT
30
XIN
IN
Terminal not used.
Internal clock oscillation frequency input setting.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit with
respect to XOUT terminal.
22
R-370EK
R-370ES
Pin No.
Signal
I/O
Description
31
XOUT
OUT
32
VSS
IN
33
P27
OUT
Terminal not used.
34
P26
OUT
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.
35
P25
OUT
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.
36
P24
OUT
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.
37
P23
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G4 line keys on key matrix is touched.
38
P22
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G3 line keys on key matrix is touched.
39
P21
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G2 line keys on key matrix is touched.
40
P20
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43-P46 terminal while one
of G1 line keys on key matrix is touched.
41-47
P17-P11
OUT
Terminal not used.
48-72
SEG24-SEG0
OUT
Segment data signal.
Connected to LCD.
The relation between signals are as follows:
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.
LSI signal (Pin No.)
LCD (Pin No.)
SEG 24 (48) ....................... SEG 24 (29)
SEG 23 (49) ....................... SEG 23 (28)
SEG 22 (50) ....................... SEG 22 (27)
SEG 21 (51) ....................... SEG 21 (26)
SEG 20 (52) ....................... SEG 20 (25)
SEG 19 (53) ....................... SEG 19 (24)
SEG 18 (54) ....................... SEG 18 (23)
SEG 17 (55) ....................... SEG 17 (22)
SEG 16 (56) ....................... SEG 16 (21)
SEG 15 (57) ....................... SEG 15 (20)
SEG 14 (58) ....................... SEG 14 (19)
SEG 13 (59) ....................... SEG 13 (18)
SEG 12 (60) ....................... SEG 12 (17)
LSI signal (Pin No.)
LCD (Pin No.)
SEG 11 (61) ...................... SEG 11 (16)
SEG 10 (62) ...................... SEG 10 (15)
SEG 9 (63) ...................... SEG 9 (14)
SEG 8 (64) ...................... SEG 8 (13)
SEG 7 (65) ...................... SEG 7 (12)
SEG 6 (66) ...................... SEG 6 (11)
SEG 5 (67) ...................... SEG 5 (10)
SEG 4 (68) ...................... SEG 4 ( 9)
SEG 3 (69) ...................... SEG 3 ( 8)
SEG 2 (70) ...................... SEG 2 ( 7)
SEG 1 (71) ...................... SEG 1 ( 6)
SEG 0 (72) ...................... SEG 0 ( 5)
73/74
VCC/VREF
IN
Connected to GND.
75
AVSS
IN
Connected to VC.
76
COM3
OUT
Common data signal: COM3.
Connected to LCD signal COM3.
77
COM2
OUT
Common data signal: COM2.
Connected to LCD signal COM2.
78
COM1
OUT
Common data signal: COM1.
Connected to LCD signal COM1.
79
COM0
OUT
Common data signal: COM0.
Connected to LCD signal COM0.
80
VL3
IN
Power source voltage input terminal.
Standard voltage for LCD.
23
R- 370EK
R- 37 0ES
ABSOLUTE HUMIDITY SENSOR CIRCUIT
1) Structure of Absolute Humidity Sensor
The absolute 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.
Thermistors
ventilation opening for sensing Sensing part
Sensing part
(Open vessel)
(Closed vessel)
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 absolute humidity
sensor, ERROR will appear on the display and the
cooking is stopped.
1) Absolute humidity sensor circuit
R3
R1
S
R2
S : Thermistor
open vessel
C : Thermistor
closed vessel
620k
11
R54
300k
12
R55
150k
13
R56
75k
17
R57
37.4k
15
R52
S
R51
3.32k R53
1.8k
VA : -15V
Absolute humidity vs,
output voltage characteristic
Absolute humidity (g/m 2 )
(3) Detector Circuit of Absolute Humidity Sensor Circuit
This detector circuit is used to detect the output voltage
of the absolute 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 R53 ~ R57. Changing
the resistance values results in that there is the same
potential at both F-3 terminal of the absolute 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. As the sensor cooking proceeds,
the food is heated to generate moisture by which the
resistance balance of the bridge circuit is deviated to
24
VA : -15V
SW1
P57
P56
P55
P51
P53
R51
47k
D90
VC : -5V
SW4
SW5
LSI
(IC1)
C50
R50
15k
SW2
SW3
AN0
0.01uF
0.01uF
R54
360k
0.1uF
+
IC2
R50
330
F-2
0.1
uF
C50
F-1
C
R52
F-3
3.57k
10
C51
47k
Output voltage
C
Operational
amplifier
Output
voltage
+
C. Thermistor in
closed vessel
S. Thermistor in
open vessel
R53
C51
(2) Operational Principle of Absolute Humidity Sensor
The figure below shows the basic structure of an absolute
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 150˚C (302˚F), 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.
9
AN1
R-370EK
R-370ES
TOUCH CONTROL PANEL SERVICING
transformer.
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
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).
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.
approx. 1M ohm
2. Shapes of Electronic Components
E
C
B
Transistor
2SB1238
E
CB
Transistor
DTA143ES
DTD143ES
3. 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 TRANSFORMER 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 power
4. 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
5. 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.
25
R- 370EK
R- 37 0ES
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)
High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, 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. Visually check the door and cavity face plate for damage
(dents, cracks, signs of arcing etc.).
4. The door is bent or warped.
5. There are defective parts in the door interlock system.
6. There are defective parts in the microwave generating
and transmission assembly.
7. There is visible damage to the oven.
Carry out any remedial work that is necessary before
operating the oven.
Do not operate the oven if any of the following conditions
exist;
1. Door does not close firmly.
2. Door hinge, support or latch hook is damaged.
3. The door gasket or seal is damaged.
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.
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 following parts;
1) High voltage parts:
Magnetron, High voltage transformer, High voltage
capacitor and High voltage rectifier assembly.
2) Hot parts:
Oven lamp, Magnetron, High voltage transformer
and Oven cavity.
3) Sharp edge:
Base plate, Oven cavity, Waveguide flange, Angles,
Guides and other metallic plates.
4) Movable parts (to prevent a fault)
Fan blade, Fan motor, Switch.
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 PANEL PARTS, DOOR PARTS’, when carrying out any of
the following removal procedures:
OUTER CASE REMOVAL
To remove the outer case, proceed as follows.
1. Disconnect the power supply cord.
2. Open the oven door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. Remove the two (2) screws from the lower portion of the
rear cabinet using a T20H Torx type or GTXH20-100
screw driver.
5. Remove the remaining three (3) screws from rear and
two (2) screws along the right and left sides of outer case.
6. Slide the entire outer case back out about 1 inch (3 cm)
to free it from retaining clips on the cavity face plate.
Special screw
Screw driver (Type: TORX T1120H
or GTXH20-100)
Figure C-1. Special screw position
26
R-370EK
R-370ES
6. Lift entire outer case from the unit.
CAUTION: 1. DISCONNECT OVEN FROM POWER SUP
PLY BEFORE REMOVING OUTER CASE.
2. DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN
COMPONENTS OR WIRING.
NOTE: When replacing the outer case, the 2 special
Torx screws must be reinstalled in the same
locations.
OVEN CAVITY ASSEMBLY REMOVAL
Before removal of the power transformer, high voltage
capacitor, high voltage rectifire, magnetron, fan motor and
turntable motor, the oven cavity must be removed from base
plate as follows.
Removal
1. Disconnect the power supply cord and then remove
outer case (refer to "OUTER CASE REMOVAL").
2. Open the oven door and block it open.
3. It is recommended that the door is removed from the
oven cavity. Refer to "DOOR REPLACEMENT".
4. Disconnect the wire leads from the power supply cord,
turntable motor, thermal cut-out (oven), thermal cut-out
(MG.), all switches on the latch hook, magnetron and
oven lamp.
5. Release the two (2) snap bands of the main wire harness
from the oven cavity.
6. Remove the two (2) screws holding the front leg to the
base plate.
7. Remove the front cover from the oven cavity by releasing
the three (3) tabs.
8. Remove the two (2) screws holding the waveguide
flange of the oven cavity to the base plate.
9. Remove the three (3) screws holding the base plate to
the oven cavity front plate.
10.Remove the three (3) screws holding the base plate to
the oven cavity back plate.
11.Lift up the oven cavity assembly and remove it from the
base plate.
12.Now the power transformer, high voltage capacitor, high
voltage rectifier and fan motor can be found on the base
plate.
13.The magnetron can be found at wavegide flange of the
oven cavity.
14. The turntable motor can be found under the oven cavity
bottom plate.
Reinstallation
1. Make sure that the electrical parts on the base plate are
reinstalled at their positions.
2. Make sure that the wire leads are reconnected to their
correct positions. Refer to the "PICTORIAL DIAGRAM".
3. Reinstall the oven cavity assembly on the base plate.
4. Hold the base plate to the oven cavity back plate with
three (3) screws.
5. Hold the base plate to the oven cavity front plate with
three (3) screws.
6. Hold the waveguide flane of the oven cavity to the base
plate with two (2) screws.
7. Reinstall the front leg to the oven cavity front plate.
8. Hold the front cover to the base plate with two (2) screws.
9. Insert the two (2) snap bands of main wire harness to the
two (2) holes of oven cavity.
10. Reconnect the wire leads to the magnetron, all switches,
thermal cut-out (MG.), thermal cut-out (oven.), oven
lamp, turntable motor and power supply cord. Refer to
the "PICTORIAL DIAGRAM" on page 32.
11. If the door has been removed, reinstall the door to the
oven cavity. Refer to "DOOR REPLACEMENT".
12. Now, the oven cavity assembly should be reinstalled.
POWER TRANSFORMER REMOVAL
Reinstallation
1. Rest transformer on the base plate with its primary
terminals toward the left side.
2. Secure transformer with four screws to base plate.
3. Re-connect wire leads (primary and high voltage) to
power transformer and filament leads of transformer to
magnetron and high voltage capacitor. Refer to
"PICTORIAL DIAGRAM".
4. Reinstall the oven cavity assembly to the base plate.
Refer to "OVEN CAVITY ASSEMBLY REMOVAL".
5. Re-install outer case and check that oven is operating
properly.
1. Disconnect the power supply cord and then remove
outer case.
2. Remove the oven cavity assembly from the base plate.
Refer to "OVEN CAVITY ASSEMBLY REMOVAL".
3. Discharge the high voltage capacitor.
4. Disconnect the wire leads (primary and high voltage)
from power transformer and the filament leads from the
magnetron and capacitor terminals.
5. Remove four (4) screws holding transformer to base
plate.
6. Remove transformer from base plate.
HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL
3. Discharge the high voltage capacitor.
4. Disconnect the high voltage wire B from the high voltage
capacitor.
5. Disconnect the filament lead (short one) of the power
1. Disconnect the power supply cord and then remove
outer case.
2. Remove the oven cavity assembly from the base plate.
Refer to "OVEN CAVITY ASSEMBLY REMOVAL".
27
R- 370EK
R- 37 0ES
transformer from the high voltage capacitor.
6. Remove one (1) screw holding capacitor holder to base
plate.
7. Remove one (1) screw holding high voltage rectifier
assembly to capacitor holder.
8. Disconnect rectifier terminal from the capacitor.
High voltage rectifier assembly is now free.
9. Remove the capacitor holder. The capacitor is now free.
CAUTION: WHEN REPLACING HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR,
GROUND SIDE TERMINAL OF THE HIGH
VOLTAGE RECTIFIER MUST BE SECURED
FIRMLY WITH A GROUNDING SCREW.
MAGNETRON REMOVAL
Reinstallation
1. Re-install the magnetron thermal duct assembly with
thermal cut-out (MG) to magnetron with the one (1)
screw.
2. Re-install the magnetron to waveguide flange with the
four (4) screws.
3. Re-install the oven cavity assembly to the base plate.
Refer to "OVEN CAVITY ASSEMBLY REMOVAL".
4. Reconnect the wire leads to the magnetron and thermal
cut-out (MG). Refer to "PICTORIAL DIAGRAM" on page
32.
5. Re-install outer case and check that the oven is operating
properly.
CAUTION: WHEN REPLACING MAGNETRON, BE SURE
THE R.F. GASKET IS IN PLACE AND MOUNTING SCREWS ARE TIGHTENED SECURELY.
Removal
1. Disconnect the power supply cord and then remove
outer case.
2. Remove the oven cavity assembly from the base plate.
Refer to "OVEN CAVITY ASSEMBLY REMOVAL".
3. Discharge the high voltage capacitor.
4. Now, the wire leads should be disconnected from the
magnetron and thermal cut-out (MG).
5. Carefully remove the four (4) screws holding magnetron
to waveguide flange.
6. Remove magnetron with care so that magnetron antenna
is not hit by any metal object around antenna.
7. Remove the one (1) screw holding the magnetron duct
assembly to the magnetron.
8. Remove the magnetron duct assembly with thermal cutout (MG) from magnetron.
9. Now, the magnetron is free.
OVEN LAMP REMOVAL
1. Disconnect the power supply cord and remove outer
case.
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 lamp.
5. Remove the one (1) screw holding the oven lamp to the
lamp angle.
6. Remove the oven lamp from the lamp angle.
7. Now, the oven lamp socket is free.
FAN MOTOR REMOVAL
*
Do not touch the pliers to the coil of the fan motor
because the coil may be cut or injured.
* Do not disfigure the bracket by touching with the
pliers.
10.Remove the fan blade from the shaft of the fan motor by
pulling and rotating the fan blade with your hand.
11. 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.
12.Remove the two (2) screws holding the fan motor to the
fan duct.
13.Now, the fan motor is free.
14.Another fan motor can be removed in a same way.
REMOVAL
1. Disconnect the power supply cord and then remove the
outer case.
2. Remove the oven cavity assembly from the base plate.
Refer to "OVEN CAVITY ASSEMBLY REMOVAL".
3. Discharge the high voltage capacitor.
4. Disconnect the wire leads from the fan motor.
5. Release the main wire harness and the switch harness
from the holes of the fan duct.
6. Remove each one (1) screw holding the separate
angles A, B and C to the base plate. And remove them
from base plate.
7. Remove two (2) screws holding the fan duct to the base
plate. And remove it from the base plate.
8. Remove the fan blade from the fan motor shaft according
to the following procedure.
9. Hold the edge of the rotor of the fan motor by using a pair
of groove joint pliers.
CAUTION:
* Make sure that no metal pieces enter the gap between
the rotor and the stator of the fan motor because the
rotor is easily shaven by pliers and metal pieces may
be produced.
INSTALLATION
1. Install the fan motor to the fan duct with the two (2)
screws.
2. Install the fan blade to the fan motor shaft according to
the following procedure.
3. Hold the center of the bracket which supports the shaft
of the fan motor on the flat table.
4. Apply the screw lock tight into the hole (for shaft) of the
28
R-370EK
R-370ES
fan blade.
5. 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 strongly when installed
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.
6. Catch two holes of fan duct on two tabs of the base plate.
7. Hold the fan duct assembly to the base plate with the two
(2) screws.
8. Re-install the separete angles A, B and C to the base
plate with each one (1) screw.
9. Insert the main wire harness and switch harness into the
holes of the fan duct.
10.Connect the wire leads to the fan motor. Referre to
"PICTORIAL DIAGRAM".
11.Re-install the oven cavity assembly to the base plate.
Refere to "OVEN CAVITY ASSEMBLY REMOVAL".
12.Reconnect all wire leads removed from components.
Referre to "PICTORIAL DIAGRAM".
Coil
Groove joint pliers
Stator
Gap
Bracket
Shaft
Shaft
These are the positions
that should be pinched
with pliers.
Axis
Stator
Rotor
Table
Center of
bracket
Rotor
Rear View
Side View
POWER UNIT REMOVAL
1. Disconnect the power supply cord and remove outer
case.
2. Open the door and back it open.
3. To discharge the high voltage capacitor, waite for 60
seconds.
4. Disconnect the wire leads and the connectors from the
power unit.
5. Remove two (2) screws holding power unit to the base
plate.
6. With needle nose pliers, nip and push the head of the
one (1) PC support clip which holds the power unit. And
then release the clip from the hole of the power unit.
7. Now the power unit is free.
Needle nose pliers
Power unit
PC support clip
Figure C-2. PC support clip
POSITIVE LOCK® CONNECTOR (NO-CASE TYPE) REMOVAL
Terminal
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. Push the lever of positive lock® connector.
5. Pull down on the positive lock® connector.
Positive lock®
connector
1
Push
Lever
CAUTION: WHEN CONNECTING THE POSITIVE LOCK®
CONNECTORS TO THE TERMINALS, CONNECT THE POSITIVE LOCK® SO THAT THE
LEVER FACES YOU
2
Pull down
Figure C-3. Positive lock® connector
TURNTABLE MOTOR REMOVAL
5. Disconnect wire leads from turntable motor.
(See "Positive lock connector removal")
6. Remove two (2) screws holding turntable motor to oven
cavity.
7. Remove the TTM packing from the turntable motor
shaft.
1. Disconnect the power supply cord.
2. Remove turntable and turntable support from oven cavity.
3. Lay the oven on it's backside. Remove the turntable
motor cover by snipping off the material in four corners.
4. Where the corners have been snipped off bend corner
areas flat.
29
R- 370EK
R- 37 0ES
8. Now the turntable motor is free.
9. After replacement use the one (1) screw to fit the
turntable motor cover.
CAUTION: NO SHARP EDGES MUST BE EVIDENT AFTER REMOVAL OF THE TURNTABLE MOTOR COVER.
DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL
Reinstallation
1. Re-install each switch in its place. The primary interlock/
monitor switches are in the lower position and the door
sensing switch is in the upper position.
2. Re-connect wire leads to each switch.
Refer to pictorial diagram.
3. Make sure that the monitor switch is operating properly
and check continuity of the monitor circuit. Refer to
chapter "Test Procedure" and Adjustment procedure.
1. Disconnect the power supply cord and remove outer case.
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 switches.
5. Push outward on the one (1) retaining tabs holding
switch in place.
6. The switch is now free.
DOOR SENSING SWITCH/PRIMARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT
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 contacts of door sensing switch and primary interlock
switch open within 1.6mm gap between right side of
cavity face plate and door when door is open.
3. Monitor switch contacts close when door is opened.
4. 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 then remove
outer case.
2. Open the door and block it open.
3. To discharge the high voltage capacitor, wait for 60
seconds.
If the door sensing switch, primary interlock switch and
monitor switch do not operate properly due to a
misadjustment, the following adjustment should be made.
4. Loosen the two (2) screws holding latch hook to the oven
cavity front flange.
5. 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 door sensing
switch and primary interlock switch are activated with the
door closed. The horizontal position of the latch hook
should be adjusted so that the plunger of the monitor
switch is pressed with the door closed.
6. Secure the screws with washers firmly.
7. Check the operation of all switches. If each switch has
not activated with the door closed, loosen screw and
adjust the latch hook position.
Door
Latch
Heads
Latch Hook
Door Sensing
Switch
Monitor Switch
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
Primary
Interlock Switch
Figure C4. Latch Switch Adjustments
DOOR REPLACEMENT
6. Remove the harness cover from the front leg.
7. Disconnect the 9-pin wire harness from the power unit
on the base plate.
8. Insert a putty knife (thickness of about 0.5mm) into the
gap between the choke cover and door frame as shown
in Figure C-5 to free engaging parts.
9. Pry the choke cover by inserting a putty knife as shown
Figure C-5.
10.Release choke cover from door panel.
11.Now choke cover is free.
REMOVAL
1. Disconnect the power supply cord and then remove the
outer case.
2. Open the door slightly.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. Remove the two (2) screws holding the front leg to the
base plate.
5. Remove the front leg from the oven cavity by releasing
the three (3) tabs.
30
R-370EK
R-370ES
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.
Putty Knife
Choke Cover
Door Frame
Pin
Upper oven
hinge
Upper
oven hinge
Figure C-5. Door Disassembly
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.
12.Release two (2) pins of door panel from two (2) holes of
upper and lower oven hinges by lifting up.
13.With pulling out the 9-pin wire harness from the hole of
the oven cavity front plate, remove the door from the
oven cavity.
14.Now, the door is free from the oven cavity.
Door frame
assembly
Slit choke of
door panel
Lower
oven hinge
Pin
REINSTALLATION
1. Re-install the front leg to the oven cavity front plate.
2. Hold the front leg to the base plate with (2) screws.
3. Insert the 9-pin wire harness to the holes of the front leg
and the oven cavity front plate.
4. Catch two (2) pins of door panel on two (2) holes of upper
and lower oven hinges.
5. Re-install choke cover to door panel by pushing.
6. Connect the 9-pin wire harness to the power unit on the
base plate.
7. Re-install the harness cover to the front leg.
8. Now the door is installed.
Note: After any service to the door;
(A) Make sure that door sensing switch and primary
interlock 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.
After any service, 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. Check for microwave leakage around door with an
approved microwave survey meter. (Refer to Microwave
Measurement Procedure.)
Choke cover
Lower
oven hinge
Figure C-6. Door Replacement
Door
9-pin wire
harness
9-pin wire
harness
Power unit
Door frame
Hole
Front leg
Base plate
Hole
Front leg
Figure C-7. Routing of 9-pin wire harness
SEALER FILM
Installation
1. Put the adhesive tape on the backing film of the sealer
film as shown in Fig. C-8.
2. Tear the backing film by pulling the adhesive tape.
3. Put the pasted side of the sealer film on the door panel.
Sealer film
Backing film
Adhesive tape
Figure C-8. Sealer film
31
R- 370EK
R- 37 0ES
INDIVIDUAL DOOR PARTS REMOVAL
PWB Cover
DOOR PANEL
1. Disconnect the power supply cord.
2. Remove the door from the oven. Refer to "DOOR
REPLACEMENT".
3. To discharge the high voltage capacitor, wait for 60
seconds.
4. The choke cover should have been removed.
5. Remove the four (4) screws holding the door panel to
the door screen.
6. Now, door panel is free.
Door frame
CPU unit
Hole of
PWB cover
9-pin wire
harness
Tab of LCD holder
Figure C-9(a). Routing of 9-pin wire harness
PWB Cover
LATCH HEAD AND LATCH SPRING
7. Slide the latch head and remove it from the door frame
assembly with releasing the latch spring from the door
frame assembly and the latch head.
8. Now, the latch head and the latch spring are free.
Tab
Tab
Hole of
PWB Cover
Tab
Hole on door frame
9-pin wire harness
CPU UNIT
7. Remove the two (2) screws holding the PWB cover to
the door frame assembly.
8. Remove the PWB cover from the door frame assembly.
9. Remove the one (1) screw holding the CPU unit to the
door frame assembly.
10.Releasing the two (2) tabs, remove the CPU unit with the
LCD holder from the door frame assembly.
11.Releasing the two (2) tabs, release the LCD from the
LCD holder.
12.Releasing the four (4) tabs, remove the LCD holder from
the CPU unit.
13.Disconnect the 9-pin wire harness from the CPU unit.
14.Disconnect the ribbon cable of the key unit from the CPU
unit.
15.Now the CPU unit is free.
Tab
Door frame
Hole on door frame
Figure C-9(b). Routing of 9-pin wire harness
NOTE: For key unit
1. Before attaching a new key unit, wipe off remaining
adhesive on the door frame surfaces completely with
a soft cloth soaked in alcohol.
2. When attaching the key unit to the door frame, adjust
the upper edge and right edge of the key unit to the
correct position of door frame.
3. Stick the key unit firmly to the door frame by rubbing
with soft cloth not to scratch.
NOTE: For CPU unit
Handle the CPU unit carefully so that the ribbon
cable does not come off. Because the ribbon cable
is glued on the LCD and the printed wiring board
only by heated paste.
DOOR FRAME ASSEMBLY
16.Releasing the four (4) tabs, remove the 9-pin wire
harness from the door frame assembly.
19.Now, the door frame assembly is free.
NOTE: For 9-pin wire harness
1. Before the PWB cover is reinstalled to the door frame
assembly, route the 9-pin wire harness under the tab
of LCD holder as shown in Figure C-9(a). And when
the PWB cover is reinstalled, route the 9-pin wire
harness under the hole of the PWB cover.
2. Before the door panel is reinstalled to the door frame
assembly, make sure that the 9-pin wire harness is
held by the four (4) tabs and two (2) holes on the door
frame assembly as shown in Figure C-9(b).
Printed wiring board
of CPU unit
Liquid Crystal
Display (LCD)
Ribbon cable
Figure C-10. CPU unit
32
1
2
3
33
4
5
WHT 9
PPL 7
GRY 8
BLU 6
GRN 5
1
CN-B
2
3
CN-F
CN-C
1
9
CN-B
1 GRN
2
9-PIN WIRE HARNESS
AH SENSOR
BLK
MONITOR
FUSE
&
HOLDER
3 GRY
CN-F
1 BLK
2 RED
3 WHT
WHT
BLK
9
W
H
T
8 7
G P
R P
Y L
CN-C
6
B
L
U
5
G
R
N
9
CN-C 1
IC1
1
B
R
N
(on the door)
4 3 2
Y O R
L R E
W G D
CPU UNIT
CN-G
RED
RED
Figure S-1. Pictorial Diagram
FAN
MOTOR
WHT
GRY
RED
BLK
WHT
WHT
N.C.
6
WHT
WHT
WHT
BLK
ORG
RED
THERMAL
CUT-OUT (MG)
OVEN LAMP
WHT
5
COM.
PRIMARY
NO
INTERLOCK
SWITCH
GRY
GRN
GRY
WHT
COM.
FAN
MOTOR
MONITOR
SWITCH
RED
TURNTABLE
MOTOR
N.O.
4
ORG 3
YLW 4
RED 2
BRN 1
CN-C
1
POWER UNIT
N.O.
GRY
RED
RED
BLK
WHT
COM.
DOOR
SENSING
SWITCH
ORG
3
COM.
RY1
N.O.
COM.
2
BLK
BLK
1 WHT
BLK
THERMAL
CUT-OUT (OVEN)
B
WHT
BLK
POWER
TRANSFORMER
A
RED
BLK
BLK
WHT
GRY
E
BLK
MAGNETRON
2
T1
H
WHT
HIGH VOLTAGE
WIRE B
HIGH VOLTAGE
CAPACITOR
1
SECONDARY
INTERLOCK
RELAY RY2
N
G
NOTE:
The grounding conductor of
the power supply cord has
been grounded by power
supply cord fixing screw.
The screw must allways be
kept tight.
F
H.V.
RECTIFIER
H
POWER SUPPLY
CORD 120V 60Hz
D
NOTE:
The neutral (WHT) wire must be
connected to the terminal with "N"
mark on the power supply cord.
C
HIGH VOLTAGE COMPONENTS
R-370EK
R-370ES
6
A
B
C
D
E
F
G
H
R- 370EK
R- 37 0ES
2
1
4
3
6
5
A
A
T1
–
ZD1
HZ16-1
–
GND
C2
VA
C3
INT
C4
OVEN LAMP
TURNTABLE
MOTOR
FAN MOTOR
C6
BUZZER
C5
MICRO
C7
DOOR
SENSING
SWITCH
C9
AHR
C8
AHA
Q1
2SB1238
R2 330 1w
C
–
c
COM
+
D22
1SS270A
R4 3.3k
Q21
DTD143ES
RY1
N.O
AC(H)
C
C21
10µ/35v
D21
1SS270A
N.O
AC(N)
OVEN LAMP
TURNTABLE
MOTOR
FAN MOTOR
D
+
SP1
PKM22EPT
COM
MICRO
RY2
D
Q22
DTA143ES
B-2
DOOR
SENSING
SWITCH
D20 1SS270A
D40 1SS270A
E
B
C1
C3 10µ/35v
b
+
R1 2.4k
D2
D4
4
(J1)
a
1
C2 1000µ/35v
d
CN-C
D1
D3
C1 0.1µ/50v
B
D1-D4
1N4002
7
VRS1
10G471K
3
CN-B
E
F
6
8
4
7
C51
0.1µ/50v
IC2
BA4558
5
C50
0.1µ/50v
R51
3.32kD 1/4w
R52
3.57kD
1/4w
B-1
F
R53 1.8kF 1/4w
R54 360kF 1/4w
F-3
F-2
F-1
R50 330 1w
NOTE
: IF NOT SPECIFIED, 1/4W, 5%
CN-F
G
G
H
H
Figure S-2. Power Unit Circuit
1
2
4
3
34
5
6
3
35
C7
DOOR
SENSING
SWITCH
NOTE
C5
C4
C6
C9
C8
C3
C2
MICRO
OVEN LAMP
TURNTABLE
MOTOR
FAN MOTOR
BUZZER
AHR
AHA
INT
VA
R9 680 1/2w
LD1 LD2 LD3 LD4
4
R40 4.7k
C1 0.1µ/50v
R20 1k
C20
0.1µ/50v
: IF NOT SPECIFIED, 1/16W ± 5%
R41 15k
Q20
DTA143EKA
Q30
DTA143EKA
Q10
DTA143EKA
C10
0.1µ
/50v
R1 82
Q1
2SA1037AK
–
A
B
R50 15k
D50
MA152WA
C3 0.01µ/25v
R57 37.4kF
R10 15k
C
D
(J12)
(J13) 4.7k
(J10)
(J11) 4.7k
CF1
CSTS4.00MG
R52 47k
R51 47k
5
CN-G
G7
25
IC1
IXA102DR
G6
G5
Compu
Defrost
Baked
Potatoes
Fresh
Rolls &
Muffins Vegetables
64
KEY UNIT
DEF HELP
41
SEG8
SEG9
SEG10
SEG11
SEG12
SEG13
SEG14
SEG15
SEG16
SEG17
SEG18
SEG19
SEG20
SEG21
SEG22
SEG23
SEG24
STOP
Clear
0
5
6
Custom
Help
4
Minute Plus
START
3
8
G1
Power
Level
G2
9
2
1
29
R60
15k
7
G3
G4
40
SEG8
SEG9
SEG10
SEG11
SEG12
SEG13
SEG14
SEG15
SEG16
SEG17
SEG18
SEG19
SEG20
SEG21
SEG22
SEG23
SEG24
P11
P12
P13
P14
P15
P16
P17
65
Fish
Beverage Ground Popcorn
Meat
Seafood
Kitchen
Timer Frozen
Reheat
Chicken
Vegetables Sensor
Breast
Clock
Rice
Frozen
Entrees
24
1
COOK SENSOR LBS
5
C61 330pF/50v
C62 330pF/50v
Figure S-3. CPU Unit Circuit
R70 15k
R69 15k
B
A
E
D
C
80
VL2
VL1
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
P57
P56
P55
CNTR0
P53
P52
P51
P50
P47
P46
P45
P44
P43
INT0
1
GND
LIQUID CRYSTAL DISPLAY
4
R68 15k
R67 15k
E
C4
0.01µ/25v
R5 15k
R2 4.7k
C11 0.01µ/25v
R4 1k
ZD1
UDZ4.3B
R55 150kF
+
R54 300k
R3 4.7k
Q2
2SA1037AK
R53 620k
(J14)
(J15) 4.7k
C51 0.01µ/25v
(J16)
(J17) 4.7k
C63 330pF/50v
C1
C40
0.01µ
/25v
R8 4.7k R7 4.7k R6 4.7k
R100
15k
GND
R56 75kF
COM0 (LCD)
COM1 (LCD)
COM2 (LCD)
COM3 (LCD)
COM0 (LCD)
COM1 (LCD)
COM2 (LCD)
COM3 (LCD)
CPU UNIT
3
R74 270k
R73 270k
R72 270k
R71 270k
C50 0.01µ/25v
R80
1M
2
R66
15k
H
R65
15k
1
VL3
COM0
COM1
COM2
COM3
AVSS
VREF
VCC
SEG0
SEG1
SEG2
SEG3
SEG4
SEG5
SEG6
SEG7
G
P41
P40
RESET
P71
P70
XIN
XOUT
VSS
P27
P26
P25
P24
P23
P22
P21
P20
F
R64
15k
D
R63
15k
C
COM0
COM1
COM2
COM3
SEG0
SEG1
SEG2
SEG3
SEG4
SEG5
SEG6
SEG7
SEG8
SEG9
SEG10
SEG11
SEG12
SEG13
SEG14
SEG15
SEG16
SEG17
SEG18
SEG19
SEG20
SEG21
SEG22
SEG23
SEG24
E
2
R62
15k
1
C60 330pF/50v
B
SEG8
SEG9
SEG10
SEG11
SEG12
SEG13
SEG14
SEG15
SEG16
SEG17
SEG18
SEG19
SEG20
SEG21
SEG22
SEG23
SEG24
A
R61
15k
CN-C
R-370EK
R-370ES
6
A
B
C
6
D
E
F
G
H
G11 G10 G 9 G 8
C2 47µ/16v
R- 370EK
R- 37 0ES
2
1
4
3
5
6
A
A
F
DIP
B
R52
9
1
CN - C
2
B
1
R50
C51
D40
R51
CN - B
C50
4
5
1
D20
3
IC2
1
Q1
E
(R3)
B
B
D
C2
D21
1
Q21
(ZD2)
(Q2) E
SP1
2
(J2)
OM
E
C1
VRS1
(J1)
DU
RY1
E
CN - A
ZD1
E
B
D
E
B
R4
C21
1
2
Q22
C
C3
R1
R53
R54
8
R2
CN - F
C
7
1
S
P
F
F
D3
3
D1
4
T1
DU
RY2
G
OM
G
D22
D2
D4
H
H
Figure S-4. Printed Wiring Board of Power Unit
1
2
4
3
36
5
6
R - 370EK
R - 3 70 E S
PARTS LIST
Note: The parts marked “∆” may cause undue microwave exposure.
The parts marked “*” are used in voltage more than 250V.
REF. NO.
PART NO.
DESCRIPTION
Q'TY
CODE
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
AQ
AG
AH
AS
AK
AQ
AV
AV
AX
BP
BK
BL
AL
AQ
AS
AK
AX
1
1
1
1
1
1
AW
AK
AC
BD
BD
AH
1
1
1
1
1
1
1
1
2
4
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
BC
AC
AF
AD
AA
AF
AA
AA
AA
AD
AA
AA
AK
AA
AC
AA
AA
AA
AA
AA
AC
AC
AA
AA
AK
AM
AG
AP
AE
AA
1
1
1
1
1
1
1
1
AH
AD
AN
AL
AE
-AL
AP
ELECTRIC PARTS
*
*
*
*
∆*
∆*
1- 1
1- 2
1- 3
1- 4
1- 5
1- 6
1- 7
1- 7
1- 8
1- 9
1-10
1-10
1-11
1-12
1-12
1-13
1-14
FACCDA085WREZ
QFSHDA024WRZZ
QSW-MA137WRE0
FFS-BA023WRK0
RTHM-A116WRE0
FH-DZA100WRKZ
RC-QZA211WRE0
RC-QZA286WRZZ
RMOTEA400WRZZ
RTRN-A638WRZZ
RV-MZA288WRE0
RV-MZA308WRZZ
RLMPTA082WRZZ
RMOTDA186WRE0
RMOTDA211WRE0
RTHM-A123WRZZ
FDTCTA212WRKZ
Power supply cord
Fuse holder
Primary interlock switch / door sensing switch
Monitor fuse 20A and monitor switch (AM51620C53Y1) assembly
Thermal cut-out 125 deg. C (MG)
High voltage rectifier assembly
High voltage capacitor
High voltage capacitor (Interchangeable)
Fan motor
Power transformer
Magnetron
Magnetron (Interchangeable)
Oven lamp
Turntable motor
Turntable motor (Interchangeable)
Thermal cut-out 125 deg. C (OVEN)
AH sensor
222222-
GDAI-A335WRWZ
GLEGPA087WRFZ
GLEGPA081WRFZ
GCABUA803WRPZ
GCABUA812WRPZ
GCOVAA291WRFZ
Base plate
Front leg
Leg
Outer case cabinet [R-370ES]
Outer case cabinet [R-370EK]
Harness cover
CABINET PARTS
1
2
3
4
4
5
POWER UNIT PARTS
3- 1
3- 1A
3- 1B
3- 1C
C1
C2
C3
C12
C50-51
D1-4
D20-22
D40
IC2
Q1
Q21
Q22
R1
R2
R4
R50
R51
R52
R53
R54
RY1
RY2
SP1
T1
VRS1
ZD1
DPWBFC179WRUZ
QCNCMA431DRE0
QCNCMA470DRZZ
QCNCMA237DRE0
RC-KZA087DRE0
VCEAB31VW108M
VCEAB31VW106M
VCEAB31VW106M
RC-KZA087DRE0
RH-DZA006PRE0
VHD1SS270A/-1
VHD1SS270A/-1
VHIBA4558//-6
VS2SB1238//-3
VSDTD143ES/-3
VSDTA143ES/1B
VRD-B12EF242J
VRS-B13AA331J
VRD-B12EF332J
VRS-B13AA331J
RR-DZA285DRZZ
RR-DZA286DRZZ
VRN-B12EK182F
VRN-B12EK364F
RRLY-A076DRE0
RRLY-A113DRE0
RALM-A014DRE0
RTRNPA111DRE0
RH-VZA032DRE0
VHEHZ161///-1
Power unit
2-pin connector (CN-B)
9-pin connector (CN-C)
3-pin connector (CN-F)
Capacitor
0.1 uF
Capacitor
1000 uF
Capacitor
10 uF
Capacitor
10 uF
Capacitor
0.1 uF
Diode (1N4002)
Diode (1SS270A)
Diode (1SS270A)
IC (BA4558)
Transistor (2SB1238)
Transistor (DTD143ES)
Transistor (DTA143ES)
Resistor
2.4k ohm
Resistor
330 ohm
Resistor
3.3k ohm
Resistor
330 ohm
Resistor
3.32k ohm
Resistor
3.57k ohm
Resistor
1.8k ohm
Resistor
360k ohm
Relay (OMIF-S-124LM)
Relay (DU24D1-1P(M)-R)
Buzzer (PKM22EPT)
Transformer
Varistor (10G471K)
Zener diode (HZ16-1)
44444444-
PHOK-A118WRFZ
LBNDKA099WRW0
PDUC-A772WRWZ
NFANJA047WREZ
PPACGA084WRF0
*************
GCOVHA423WRFZ
LANGQA531WRWZ
Latch hook
Capacitor holder
Fan duct
Fan blade
TTM packing
Oven cavity (Not a replaceable part)
Choke cover
Lamp angle
50V
35V
35V
35V
50V
1/4W
1W
1/4W
1W
±0.5%
±0.5%
±1.0%
±1.0%
1/4W
1/4W
1/4W
1/4W
OVEN PARTS
∆
∆
1
2
3
4
5
6
7
8
37
R- 370EK
R-370ES
REF. NO.
4- 9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20
4-21
4-22
4-23
4-24
4-25
4-26
4-27
4-28
4-29
4-30
4-31
PART NO.
PCOVPA361WREZ
LANG-A084WRFZ
LANG-A085WRFZ
LANG-A086WRFZ
PCLI-A002WREZ
FANG-A013WRYZ
LANGFA200WRPZ
NCPL-A053WRFZ
PCUSUA571WRPZ
PDUC-A775WRTZ
PPACGA181WREZ
PPACGA182WREZ
PCUSUA573WRPZ
PCUSUA313WRP0
PCUSUA578WRPZ
PCUSUA577WRPZ
PCUSGA561WREZ
PCUSUA583WRPZ
PCUSUA375WRP0
PCUSGA560WREZ
PCUSUA157WRP0
PCUSGA563WREZ
PCUSGA564WREZ
DESCRIPTION
Waveguide cover
Separate angle A
Separate angle B
Separate angle C
PC support clip
Magnetron duct assembly
Support angle
Coupling
Cushion
Exhaust duct
Cushion
Cushion
Cushion
Cushion
Cushion
Cushion
Cushion
Cushion
Cushion
Cushion
Cushion
Cushion
Cushion
5- 2
5- 3
5- 3
5-3-1
5-3-2
5- 4
5- 5
5- 6
5- 7
5- 8
5- 9
5-10
5-11
5-12
5-13
5-14
FDORFA347WRTZ
PSHEPA775WREZ
FWAKPA316WRKZ
FWAKPA318WRKZ
FUNTKB060WREZ
HPNL-A762WRRZ
LSTPPA193WRFZ
MSPRTA202WREZ
DPWBFC176WRKZ
LHLD-A236WRFZ
PSHEPA786WREZ
FW-VZA272DREZ
PCOVPA372WRWZ
PCUSUA567WRPZ
XEPSD38P08000
XEPSD30P08XS0
LHLD-A237WRFZ
Door panel
Sealer film
Door frame assembly [R-370ES]
Door frame assembly [R-370EK]
Key unit
Door screen
Latch head
Latch spring
CPU unit
LCD holder
LED sheet
9-pin wire harness
PWB cover
Cushion
Screw : 3.8mm x 8mm
Screw : 3mm x 8mm
Light guide
6- 1
6- 2
6- 3
6- 4
6- 5
6- 6
6- 7
6- 8
6-12
FROLPA079WRK0
NTNT-A079WRF0
FW-VZB827WREZ
QW-QZA242WRZZ
TCAUAA265WRRZ
TCAUAA254WRR0
TINSEA888WRRZ
FW-VZB828WREZ
FW-VZB802WREZ
Turntable support
Turntable tray
Main wire harness
High voltage wire B
DHHS caution label
Monitor caution label
Instruction book
Switch harness
T.T. motor harness
Q'TY
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
CODE
AD
AG
AG
AG
AD
AP
AD
AE
AH
AP
AH
AC
AC
AF
AG
AC
AC
AG
AH
AB
AC
AH
AH
1
1
1
1
1
1
1
1
1
1
1
1
1
1
4
3
1
AX
AH
BF
BF
AV
AU
AE
AD
BD
AC
BB
AL
AF
AE
AA
AA
AL
1
1
1
1
1
1
1
1
1
AP
AR
AW
AF
AC
AC
AF
AK
AF
8
1
6
1
2
2
9
2
2
1
4
1
7
2
2
4
1
2
AA
AA
AA
AC
AA
AB
AA
AC
AA
AA
AA
AA
AA
AA
AA
AA
AA
AB
DOOR PARTS
∆ 5- 1
∆
∆
∆
MISCELLANEOUS
*
SCREWS,NUTS AND WASHERS
7- 1
7- 2
7- 3
7- 4
7- 5
7- 6
7- 7
7- 8
7- 9
7-10
7-11
7-12
7-13
7-14
7-14
7-15
7-16
7-17
XHPSD40P08K00
XHPSD40P08000
XOTSD40P08000
LX-CZA073WRE0
XOTSD40P12000
XHPSD30P08XS0
XHTSD40P08RV0
LX-CZA070WRE0
LX-CZ0052WRE0
XHPSD30P06000
XHTSD40P08000
XHTSD40P12RV0
XOTSD40P12RV0
XOTSE40P08000
XOTSF40P08000
LX-EZA060WREZ
XOTSD40P12000
XHBWW30P08000
Screw :
Screw :
Screw :
Special
Screw :
Screw :
Screw :
Special
Special
Screw :
Screw :
Screw :
Screw :
Screw :
Screw :
Special
Screw :
Screw :
4mm x
4mm x
4mm x
screw
4mm x
3mm x
4mm x
screw
screw
3mm x
4mm x
4mm x
4mm x
4mm x
4mm x
screw
4mm x
3mm x
8mm
8mm
8mm
12mm
8mm
8mm
(Torx tamper proof screw)
6mm
8mm
12mm
12mm
8mm [R-370ES]
8mm [R-370EK]
12mm
8mm
38
R - 370EK
R - 3 70 E S
HOW TO ORDER REPLACEMENT PARTS
To have your order filled promptly and correctly, please furnish the following information.
1. MODEL NUMBER
2. REF. NO.
3. PART NO.
4. DESCRIPTION
Order Parts from the authorized SHARP parts Distributor for your area.
Defective parts requiring return should be returned as indicated in the Service Policy.
TOP PAD ASSEMBLY
FPADBA451WRKZ
DOOR PROTECTION SHEET
SPADPA204WRE0
PACKING AND ACCESSORIES
WRAP COVER
SSAKHA072WREZ
CABINET COVER
FORM SHEET
SPAKHA018WREZ
SPAKHA017WREZ
6-7 INSTRUCTION BOOK
& PRINTING MATTER
BOTTOM PAD ASSEMBLY
6- 2
TURNTABLE TRAY
FPADBA453WRKZ
6- 1 TURNTABLE SUPPORT
TRAY PAD
INTO THE
OVEN CAVITY
SPADFA499WREZ
Not replaceable items.
39
PACKING CASE
SPAKCD578WREZ [R-370ES]
SPAKCD580WREZ [R-370EK]
R- 370EK
R-370ES
2
1
4
3
6
5
OVEN AND CABINET PARTS
7-13
4-17
2-4
A
7-17
4-28
A
7-14
1-14
7-4
4-18
7-8
4-28
4-26
B
B
6-6
1-13
4-25
4-24
1-1
7-14
4-27
7-12
4-19
C
C
6-5
7-13
7-7
7-11
4-6
4-21
1-9
4-23
7-11
D
D
4-9
7-9
7-15
4-22
7-3
4-31
4-16
7-1
7-11
4-30
1-4
4-15
7-7
4-11
4-4
4-5
7-2
7-1
1-12
E
E
1-11
2-2
7-1
4-8
1-3
4-1
7-7
1-8
1-5
7-5
7-1
x2
4-3
1-2
7-7
2-5
4-4
x2
1-8
7-3
4-12
1-4
F
4-14
7-5
7-10
F
1-3
7-7
7-6
7-3
4-20
7-7
3-1
1-10
6-2
4-2
7-1
4-10
4-13
x2
1-6
1-7
G
G
4-29
7-13
2-1
6-1
7-3
H
H
2-3
7-16
1
2
4
3
40
5
6
R - 370EK
R - 3 70 E S
2
1
4
3
6
5
A
A
DOOR PARTS
5-10
5-13
5-11
5-9
5-13
5-12
B
4-7
5-6
5-7
B
5-12
5-2
5-14
5-6
5-8
5-1
5-12
5-3
C
C
5-3-1
5-12
D
D
5-4
5-3-2
5-5
MISCELLANEOUS
E
E
6-3
6-8
6-4
(CAPACITOR)
F
F
6-9
Actual wire harness may be different from illustration.
G
G
H
H
1
2
4
3
41
5
6
R- 370EK
R-370ES
COPYRIGHT © 2001 BY SHARP CORPORATION
ALL RIGHTS RESERVED.
No part of this publication may be reproduced,
stored in retrieval systems, or transmitted in any
form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior
written permission of the publisher.
2001 SHARP CORP. (4S2.530E) Printed in U.S.A
42