Beko MWDR24100SS24 User manual

1
In the interest of user-safety the unit should be restored to its original condition and only parts identical to those specified should
be used.
WARNING TO SERVICE PERSONNEL:
This service manual is intended for use by persons having electrical and mechanical training and a level of
knowledge of these subjects generally considered acceptable in the appliance repair trade. Viking Range
Corporation cannot be responsible, nor assume any liability, for injury or damage of any kind arising from the
use of this manual.
S11M447MWDR24
MICROWAVE DRAWER MODEL
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................................................................................................................. 3
MICROWAVE MEASUREMENT PROCEDURE..................................................................................................... 4
FOREWORD AND WARNING & CONTACT INFO................................................................................................. 5
PRODUCT SPECIFICATIONS ............................................................................................................................... 6
SCHEMATICS ...................................................................................................................................................... 10
TEST PROCEDURES.......................................................................................................................................... 11
MICROWAVE DRAWER DISASSEMBLY............................................................................................................. 25
WIRING DIAGRAMS ............................................................................................................................................ 33
PARTS LIST ......................................................................................................................................................... 34
PACKING AND ACCESSORIES .......................................................................................................................... 40
This document has been published to be used for after sales service only. The contents are subject to change without notice.
BEKO SERVICE MANUAL
MWDR24100SS

2
PRECAUTIONSTO BE OBSERVED BEFORE AND DUR-
ING 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 compart-
ments, 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 BEKO immediately @
[phone].
If the unit operates with the door open, service person should 1) tell the user not to operate the oven and 2)
contact BEKO and Food and Drug Administration's Center for Devices and Radiological Health
immediately.
Service personnel should inform BEKO of any certified unit found with emissions in excess of 4mW/
cm2. The owner of the unit should be instructed not to use the unit until the oven has been brought into
compliance.
DANGER CAUTION
HIGH VOLTAGE
Do not energize a microwave oven with the outer case cabinet removed, because a microwave oven gener-
ates High Voltage in the circuit.
If you intend to operate the oven employing the high frequency switching power converter circuit, you should
take special precautions to avoid an electrical shock hazard.
The high voltage transformer, high voltage capacitor and high voltage diode have energized high voltage
potential approx. 8 KV.
The aluminium heat sink is connected to the switching power transistor Collector pole, and has an energized
high voltage potential approx. 650V peak.
DO NOT ACCESS THE HIGH VOLTAGE TRANSFORMER, HIGH VOLTAGE CAPACITOR, HIGH VOLTAGE
DIODE AND HEAT SINK WHEN THE POWER SUPPLY IS CONNECTED TO AN ELECTRICAL OUTLET.

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WARNING TO SERVICE PERSONNEL
Microwave Oven units 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, Heating Elements, etc..
Read the Service Manual carefully and follow all instructions.
Before Servicing
1. Disconnect the power supply cord , and then
remove cabinet.
2. Open the drawer and keep it open.
3. Discharge high voltage capacitor.
WARNING: RISK OF ELECTRIC SHOCK.
DISCHARGE THE HIGH-VOLTAGE
CAPACITOR BEFORE SERVICING.
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
high-voltage capacitor (that is the connecting lead of the
high-voltage rectifier) against the chassis with the use of
an insulated screwdriver.
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
neccessary covers.
2. Open the drawer and keep 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
covers.
2. Open the drawer and keep it open.
3. Discharge high voltage capacitor.
4. Reconnect the leads to the primary of the power
transformer.
5. Reinstall the covers.
6. Reconnect the power supply cord.
7. Run the unit and check all functions.
After repairing
1. Reconnect all leads removed from components during
testing.
2. Reinstall the covers.
3. Reconnect the power supply cord.
4. Run the oven and check all functions.
Microwave ovens should not be operated empty. To test for
the presence of microwave energy within a cavity, place a
cup of cold water on the oven tray, close the drawer 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 re-examine
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.

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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/cm2at 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/cm2at any point 5cm or more
from the external surface of the oven.
2) Safety interlock switches:
Primary interlock relay 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.
Survey instruments that comply with the requirement for instrumentation as prescribed by CSA and NHW performance
standard for microwave ovens must be used for testing recommended instruments are , NARDA 8100 and NARDA 8200.
2) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5O C (68OF) 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 non conductive 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.
3) Set the cooking control on Full Power Cooking Mode.
4) Close the drawer 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-drawer leakage test (microwave measurement):
1) Grasp the probe of the survey instrument and hold it perpendicular to the gap between the drawer 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 drawer 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 drawer, pull the drawer away from the front of the oven as far as is permitted
by the closed latch assembly.
4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2,
and that the primary interlock switch/secondary interlock relay does turn the oven OFF before any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report.

5
SERVICE MANUAL
BEKO
MICROWAVE DRAWER
MWDR24100SS
FOREWORD
This Manual has been prepared to provide BEKO products Service Personnel with Operation and Service Information for
the BEKO MICROWAVE DRAWER.
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.
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 not any other visible damage with the oven.
Servicing and repair work must be carried out only by trained service personnel.
DANGER
Certain initial parts are intentionally not grounded and present a risk of electrical shock only during servicing.
Service personnel - Do not contact the following parts while the appliance is energized;
HighVoltage Capacitor, PowerTransformer, Magnetron, HighVoltage 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.
∆
https://www.bekoappliances.com/
SERVICE SUPPORT
[phone]
Monday through Friday 8 a.m. – 5:30 p.m. CST

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ITEM DESCRIPTION
Power Requirements Canada - 117 Volts / 13.0 Amperes / 1500 Kw / 60 Hz (CUL)
U.S.A. - 120 Volts / 13.6 Amperes / 1500 Kw / 60 Hz (UL)
Single phase, 3 wire grounded
DOE Standby Compliant Model
Power Output 950 watts (IEC TEST PROCEDURE)
Operating frequency of 2450MHz
Cooking Cavity Dimensions Width 17-11/32
Height 7-7/8"
1.2 Cubic Feet Depth 16-37/64"
Outside Dimensions Width 23-7/8"
Height 15-3/4"
Depth 23-1/16"
Packing Case Dimensions Width 29"
Height 21-1/2"
Depth 27-3/4"
(Packed unit) 86 Lbs
Control Complement Touch Control System
Clock ( 1:00 - 12:59 )
Timer (0 - 99 min. 99 seconds)
Microwave Power for Variable Cooking
Repetition Rate;
P-HI .................................................. Full power throughout the cooking time
P-90..................................................................... approx. 90% of Full Power
P-80..................................................................... approx. 80% of Full Power
P-70..................................................................... approx. 70% of Full Power
P-60..................................................................... approx. 60% of Full Power
P-50..................................................................... approx. 50% of Full Power
P-40..................................................................... approx. 40% of Full Power
P-30 .................................................................... approx. 30% of Full Power
P-20..................................................................... approx. 20% of Full Power
P-10..................................................................... approx. 10% of Full Power
P-0..................................................... No power throughout the cooking time
Setup/Help, Melt, Beverage Center, Sensor Popcorn, Sensor Cook, Sensor
Reheat, Soften, Warm, Keep Warm, Defrost, Reheat, Control Lock On/Off,
Open, Close, Start Add-A-Minute, Stop/Clear, Number Selection, Power Level,
Timer/Clock
Oven Cavity Light Yes
Safety Standard Canadian Standards Association
Health Canada, Industry Canada
UL Listed FCC Authorized
DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J
MICROWAVE DRAWER SPECIFICATION

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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 (U.S.A.), 117 volt
60 Hz (Canadian) 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.
Where a two-pronged wall-receptacle is encountered, it is the
personal responsibility and obligation of the customer to contact a
qualified electrician and have it replaced with a properly grounded
three-pronged wall receptacle or have a grounding adapter prop-
erly grounded and polarized. If an extension cord must be used,
it should be a 3-wire, 15 amp. or higher rated cord. Do not drape
over a counter top or table where it can be pulled on by children or
tripped over accidentally.
3-Pronged
Plug
Grounded
Receptacle Box
Grounding Pin
3-Pronged Receptacle
CAUTION: DO NOT UNDER ANY CIRCUMSTANCES
CUT OR REMOVE THE ROUND GROUND-
ING PRONG FROMTHIS PLUG. ALSO,"DO
NOT USE AN EXTENSION CORD".
OVEN DIAGRAM
GENERAL INFORMATION
KEY SHEET
NOTE:
The directed features (e.g.+30 sec) are disabled after 1 minute when the oven is not in use.These features are re-enabled
when the door is opened and closed or the STOP/CLEAR pad is pressed.
1 Control panel
2
3
Waveguide cover DO NOT REMOVE
Drawer Microwave Menu Label
4 Drawer sealing surfaces
5 Drawer light
6 Drawer Microwave guides
7 Vent
8 Nameplate: open the Drawer Microwave
fully. The label is beyond the back wall of
the microwave cavity facing up from the
flat surface.
2
1
5
4
3
7
6
8

8
OPERATION
DESCRIPTION OF OPERATING SEQUENCE
The following is a description of component functions dur-
ing oven operation.
OFF CONDITION
Closing the drawer activates the door sensing switch and
secondary interlock switch. (In this condition, the monitor
switch contacts are opened.)
When oven is plugged in, 120 volts A.C. is supplied to the
power unit. (Page 10).
1. The display will show flashing "EnjoyYour DrawerTouch
Clear and Touch 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 and then a Number pad.
When the START pad is touched, the following operations
occur:
1. The contacts of relays are closed and components
connected to the relays are turned on as follows.
(For details, refer to Page 10)
RELAY CONNECTED COMPONENTS
RY-1 Oven lamp
RY-2 Power transformer
RY-3 Stirrer motor
RY-4 Fan motor
2. 120 volts A.C. is supplied to the primary winding of the
power transformer and is converted to about 3.3 volts
A.C. output on the filament winding, and approximately
2370 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 feed-
box, 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 drawer is opened during a cook cycle, the
monitor switch, door sensing switch, secondary interlock
switch, relay (RY1) and primary interlock relay are
activated with the following results.The circuits to the stir
fan motor, the cooling fan motor, 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 secondary interlock switch and secondary interlock
relay and is mechanically associated with the drawer so
that it will function in the following sequence.
8. When the drawer opens from the closed position, the
primary interlock relay (RY2) and secondary interlock
switch open their contacts. And contacts of the relay
(RY1) remains closed.Then the monitor switch contacts
close.
9. When the drawer is closed from the open position, the
monitor switch contacts open first. Then the contacts of
the secondary interlock switch and door sensing switch
close. And contacts of the relay (RY1) open.
If the secondary interlock switch and primary interlock
relay (RY2) fail with the contacts closed when the drawer
is opened, the closing of the monitor switch contacts will
form a short circuit through the fuse, secondary interlock
switch, relay (RY1) and secondary interlock relay (RY2),
causing the fuse to blow.
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 (RY-2) which is operated by
the power unit within a 32 second time base. Microwave
power operation is as follows:
VARI-MODE ON TIME OFF TIME
Power 10(P-HI) 32 sec. 0 sec.
(100% power)
Power 9(P-90) 30 sec. 2 sec.
(approx. 90% power)
Power 8(P-80) 26 sec. 6 sec.
(approx. 80% power)
Power 7(P-70) 24 sec. 8 sec.
(approx. 70% power)
Power 6(P-60) 22 sec. 10 sec.
(approx. 60% power)
Power 5(P-50) 18 sec. 14 sec.
(approx. 50% power)
Power 4(P-40) 16 sec. 16 sec.
(approx. 40% power)
Power 3(P-30) 12 sec. 20 sec.
(approx. 30% power)
Power 2(P-20) 8 sec. 24 sec.
(approx. 20% power)
Power 1(P-10) 6 sec. 26 sec.
(approx. 10% power)
Power 0(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.

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SENSOR COOKING CONDITION
Using the SENSOR function, food is cooked without figur-
ing time, power level or quantity. When the oven senses
enough steam from the food, it relays the information to its
microprocessor which will calculate the remaining cooking
time and power level needed for best results. When the food
is cooked, water vapor is developed. the sensor "senses"
the vapor and its resistance increase gradually. When the
resistance reaches the value set according to the menu,
supplementary cooking is started.
The time of supplementary cooking is determined by experi-
ment with each food category and inputted into the LSI. An
example of how sensor works: (Potatoes)
1. Potatoes at room temperature. Vapor is emitted very
slowly.
MICROWAVE
2.Heat Potatoes. Moisture and humidity is emitted very
rapidly. You can smell the aroma as it cooks.
MICROWAVE
AH SENSOR
3.Sensor detects moisture and humidity and calculates
cooking time and variable power.
Cooking Sequence.
1. Touch one of the SENSOR pads.
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, 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 drawer 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 drawer 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 drawer or touching the STOP/CLEAR pad,
the time of the day will reappear on the display and the
oven will revert to an OFF condition. When the timer
reaches zero, an audible signal sounds.

10
SCHEMATIC (OFF CONDITION)
VRS1
FUSE 1
RY1 (NO)
RY1 (COM)
RY2 (COM)
RY2 (NO)
2

11
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
(A ~ P) which will be found in the "Test Procedure "section (starting on Page 13).
IMPORTANT: If the oven becomes inoperative because of a blown monitor fuse, check the primary switch, and monitor
switch, before replacing the monitor fuse. If the monitor fuse is replaced, the monitor switch must also be
replaced.
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 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.

12
TROUBLESHOOTING CHART
CK = Check / RE = Replace
Display does not operate properly when
STOP/CLEAR key is touched.
(Buzzer should sound and ":" or time of
day should appear in display.)
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.)
AH sensor does not end during sensor
cooking condition. (Oven does not shut
o after a cup of water is boiling by
sensor cooking)
TEST PROCEDURE REFERENCE LETTER
SECONDARY/THIRD INTERLOCK SWITCH PRIMARY/THIRD OR STOP SWITCH
DM FUSE
DM FUSE
SWITCHING POWER SUPPLY
Q

13
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
unlike conventional microwave ovens, proper maintenance cannot be performed with only a voltmeter
and ohmmeter.
In this service manual, the touch control panel assembly is divided into three units, Control Unit, Key-
board Unit, Switching Regulator and Switching Power Supply. Troubleshooting by unit replacement is
described according to the symptoms indicated.
Before testing,
1) Disconnect the power supply cord, and then disassemble as per "MICROWAVE DRAWER
DISASSEMBLY" page 25.
2) Open the drawer 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.
1. Keyboard Unit.
NOTE ;
1) Check Keyboard unit connection before replacement.
2) Reconnect all leads removed from components during testing.
3) Re-install the covers.
4) Reconnect the power supply cord after the covers are installed.
5) Run the oven and check all functions.
The following symptoms indicate a defective keyboard unit.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching a number pad, two figures or more are displayed.
c) When touching the pads, sometimes a pad produces no signal.
If the Keyboard unit is defective.
1) Disconnect the power supply cord, and then remove covers.
2) Open the drawer and block it open.
3) Discharge high voltage capacitor.
4) Replace the Hidden Control Panel Hinge Assembly which contains the Key Unit.
5) Reconnect all leads removed from components during testing.
6) Re-install the covers.
7) Reconnect the power supply cord after the covers are installed.
8) Run the oven and check all functions.
2. Control Unit
The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the Keyboard unit test (Procedure B) to determine if control unit is faulty.
2-1 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.
2-2 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.
3. Power Unit or Switching Power Supply
a) Fan motor, stirrer motor, oven lamp or electrical parts do not turn on or do not turn off.
b) Digital display on the control unit does not show anything.
When testing is completed,
1) Disconnect the power supply cord, and then disassemble as per "MICROWAVE DRAWER
DISASSEMBLY" page 25.
2) Open the drawer and block it open.
3) Discharge high voltage capacitor.
A TOUCH CONTROL PANEL ASSEMBLY TEST
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore,

14
C RELAY TEST
4) Reconnect all leads removed from components during testing.
5) Re-install the covers.
6) Reconnect the power supply cord after the covers are installed.
7) Run the oven and check all functions.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
B KEY UNIT TEST
1. Disconnect the power supply cord, and then remove outer case.
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.
7. Remove the outer case and check voltage between pins A1~A2 which should equal 120Vac with an
A.C. voltmeter , then pins C1-C5 which should be 24Vdc on the power unit with an D .C. voltmeter.
The meter should indicate both the 120 volts AC and 24 volts DC , if not check the switching power
supply voltages (and harness wires for break/ shorts). If it you have the voltages as stated above
and there is still no operation then check oven circuit RY1, RY2, RY3 and RY4 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, then
the power unit is defective.
RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS
RY1 Approx. 26V D.C. Oven lamp / Common
RY2 Approx. 25V D.C. Power transformer
RY3 Approx. 26V D.C. Stirrer motor
RY4 Approx. 26V D.C. Fan motor
8.Disconnect the power supply cord, and then remove outer case.
9.Open the door and block it open.
10.Discharge high voltage capacitor.
11.Reconnect all leads removed from components during testing.
2. Open the drawer and block it open.
3. Discharge high voltage capacitor.
4. 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 drawer is closed and open when the
drawer is open. If the door sensing switch (stop switch) is good,
disconnect the flat ribbon cable that connects the key unit to the
power unit and make sure the drawer sensing switch is closed (either
close the drawer 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 power unit responds
by clearing with a beep the key unit is faulty and must be replaced.
If the power 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 power unit) to determine if the power unit or key
pad is at fault.
5. Reconnect all leads removed from components during testing.
6. Re-install the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
STOP/
CLEAR
REHEAT
6
START
Add-A-Minute
1
2
7
SENSOR
REHEAT
DEFROST
9
8
3
4
OPEN
SENSOR
POPCORN
KEEP
WARM
TIMER
CLOCK
CLOSE
0
5
POWER
LEVEL
Setup/Help
CONTROL
LOCK
ON/OFF
J-1
J-2
J-3
J-4
J-5
J-6
J-7
J-8
J-9
J-12
J-11
J-10
<KEY UNIT>
SENSOR
COOK
WARM
SOFTEN

15
WARNING : The oven should be fully assembled before following procedure.
(1) Place one cup of water in the center of the tray in the oven cavity.
(2) Close the drawer, touch the Defrost pad. Then select Steaks/Chops by touching the number pad
2. And touch the number pad 5. (Now, weight 0.5lb is set.) And then touch the start pad.
(3) The oven is in Defrost cooking condition.
(4) The oven will operate as follows
WEIGHT 1ST STAGE 2ND STAGE 3RD. STAGE
LEVEL TIME LEVEL TIME LEVEL TIME
0.5lb 60% 20sec. 40% 20sec. 30% 45sec.
(5) If improper operation is indicated, the control unit is probably defective and should be checked.
D DEFROST TEST
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 function.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
E PROCEDURES TO BE TAKEN WHEN THE FUSE IS OPEN
To protect the electronic circuits, this model is provided with a fuse added to the primary on the
Noise Filter Unit. In addition, there is a non-replaceable fuse on the Switching Power Supply.
1. Fuse check and repairs.
1) Disconnect the power supply cord.
2) Remove the outer case cabinet.
3) Open the door and block it open.
4) Discharge high voltage capacitor.
5) If the Fuse is blown, replace fuse. Also do filter test per procedure N.
6) Make a visual inspection of the varistors on Noise Unit as well as Switching Power Supply. Check for
burned damage. If the varistor on Switching Power Supply has burned damage, replace Switching
Power Supply. If the varistors on Noise Unit has burned damage replace Noise Filter Unit .
8) Reconnect all leads removed from components during testing.
9) Re-install the outer case (cabinet).
10) Reconnect the power supply cord after the outer case is installed.
11) Run the oven and check all functions.
2. Follow the troubleshooting guide given below, if power is not restored after above check and
repairs are finished.
1) Disconnect the power supply cord.
2) Remove the outer case cabinet.
3) Open the door and block it open.
4) Discharge high voltage capacitor.
5) Disconnect the leads to the primary of the power transformer.
6) Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
7) After that procedure, re-connect the power supply cord.
8) Follow the troubleshooting guide given below for repair.
STEPS OCCURANCE CAUSE OR CORRECTION
The rated AC voltage is NOT present
across Switching Power Supply CN101
(pins 1,3)
No power to Switching Power Supply. Check
for wire breaks, open thermal cutouts.
1
2
3
24Vdc is NOT present across
Switching Power Supply CN201
(pins 1,2)
24Vdc is present across
Power Unit CN-C (pins 1,5) /and/
The rated AC voltage is present across
Power Unit CN-A (pins 1,3)
Switching Power Supply not operating. Re-
place Switching Power Supply.
Normal power is being received by Power
Unit but Power Unit is not operating. Replace
Power Unit.

16
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 95οF (35οC).
(3) The unit should not be installed in any area where heat and steam are generated.The unit should not be
installed, for example, next to a conventional surface unit. Refer to the “INSTALLATION INSTRUCTIONS”
of the operation manual.
(4) Exhaust vents are provided on the back of the unit for proper cooling and air flow in the cavity. To permit
adequate ventilation, be sure to install so as not to block these vents. There should be some space for
air circulation.
(5) Be sure the exterior of the cooking container and the interior of the oven are dry. Wipe off any moisture
with a dry cloth or paper towel.
(6) The Sensor works with food at normal storage temperature. For example, chicken pieces would be at
refrigerator temperature and canned soup at room temperature.
(7) Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings. The sensor
will detect the vapor given of by the spray and turn off before food is properly cooked.
(8) If the sensor has not detected the vapor of the food, ERROR will appear and the oven will shut off.
Water load cooking test
WARNING : The oven should be fully assembled before following procedure.
Make sure the oven has been plugged in at least two minutes before checking sensor cook operation. The
cabinet should be installed and screws tightened.
(1) Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.
(2) Place the container on the center of tray in the oven cavity.
(3) Close the drawer.
(4) Touch the TIMER/CLOCK pad once, the POWER LEVEL pad twice and the START pad once. And touch
the number pad 1 once and the number pad 4 once. Now, the oven is in the sensor cooking condition,
and "AH20" and "ON" 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 no ERROR code is displayed, then the AH sensor
is normal. Check other parts except the AH sensor.
TESTING METHOD FOR AH SENSOR AND/OR POWER 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 disassemble as per "MICROWAVE DRAWER
DISASSEMBLY" page 25.
(2) Open the drawer 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 covers.
(8) Reconnect the power supply cord after the covers are 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.
F AH SENSOR TEST
Checking the initial sensor cooking condition
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
9) Disconnect the power supply cord, and then remove outer case.
10) Open the door and block it open.
11) Discharge high voltage capacitor.
12) Reconnect all leads removed from components during testing.
13) Re-install the outer case (cabinet).
14) Reconnect the power supply cord after the outer case is installed.
15) Run the oven and check all functions.

17
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
9-2. Place the container on the center of tray in the oven cavity.
9-3. Close the drawer.
9-4. Touch the TIMER/CLOCK pad once, the POWER LEVEL pad twice and the START pad once. And
touch 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 does not operate properly, the problem is with the power unit, and refer to explanation below.
CHECKING POWER UNIT
(1) Disconnect the power supply cord, and then disassemble as per "MICROWAVE DRAWER
DISASSEMBLY" page 25.
(2) Open the drawer and block it open.
(3) Discharge high voltage capacitor.
(4) Disconnect the sensor connector that is mounted to control panel.
(5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of power unit.
(6) Disconnect the leads to the primary of the power transformer.
(7) Ensure that these leads remain isolated from other components and oven chassis by using insulation
tape.
(8) After that procedure, re-connect the power supply cord.
(9) Check the sensor cook operation proceed as follows:
9-1. Close the door. Touch the TIMER/CLOCK pad once, the POWER LEVEL pad twice and the START
pad once. And touch the number pads 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 power unit is probably defective.
If the above is proper, the AH sensor is probably defective.
(10) Disconnect the power supply cord, and then remove covers.
(11) Open the drawer and block it open.
(12) Discharge high voltage capacitor.
(13) Disconnect the dummy resistor circuit from the sensor connector of power unit.
(14) Carry out necessary repair.
(15) Reconnect all leads removed from components during testing and repairing.
(16) Re-install the covers.
(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.
R1, R2 : 22Ω± 1% 1/2W
R3 : 4.3kΩ± 5% 1/4W
R4 : 1MΩ± 5% 1/4W
Plunger
NC
NO
COM
COM NO
NC
R3 R4
R1
R2
1
2
3
F-1
F-2
F-3
To connector (F)
on Power Unit.
CONNECTOR

18
2. Open the drawer and keep it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. 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.
5. 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.
6. Reconnect all leads removed from components during testing.
7. Reassemble the unit.
8. Reconnect the power supply cord.
9. 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.
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: This test will require a 16 ounce (453cc) measuring cup and an accurate mercury
thermometer or thermocouple type temperature tester. For accurate results, the following procedure must
be followed carefully:
1. Fill the measuring cup with 16 oz. (453cc) of tap water and measure the temperature of the water with
a thermometer or thermocouple temperature tester. Stir the thermometer or thermocouple through the
water until the temperature stabilizes. Record the temperature of the water.
2. Place the cup of water in the oven. Operate oven at POWER 10(HIGH) selecting more than 60 seconds
cook time. Allow the water to heat for 60 seconds, measuring with a stop watch, second hand of a watch
or the digital read-out countdown.
3. Remove the cup from the oven and again measure the temperature, making sure to stir the thermometer
or thermocouple through the water until the maximum temperature is recorded.
4. Subtract the cold water temperature from the hot water temperature. The normal result should be 28οto
54οF (16οto 30οC) 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 117/120 volts and the oven cavity is clean.
G MAGNETRON ASSEMBLY TEST
1. Disconnect the power supply cord.
2. Open the drawer and keep it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. A continuity check across the DM Fuse terminals should indicate a closed circuit unless the
temperature of the thermal cut-out reaches approximately 293οF(145οC).
An open DM Fuse indicates overheating of the oven, exchange the oven DM Fuse and check inside
of oven cavity and for improper setting of cooking time or operation of power unit. Check for restricted
air flow through the vent holes of the oven cavity, especially the cooling fan and air guide.
5. Reconnect all leads removed from components during testing.
6. Reassemble the unit.
7. Reconnect the power supply cord.
8. Run the unit and check all functions.
CAUTION: IF THE DM FUSE INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE, REPLACE
DM FUSE.
H THERMAL CUTOUT TEST
1. Disconnect the power supply cord.
Refer to the disassembly instructions found on Page 25.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST

19
I SECONDARY INTERLOCK / THIRD DOOR SWITCH TEST
STOP SWITCH
1. Disconnect the power supply cord.
2. Open the drawer and keep it open.
3. To discharge 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 drawer open and a closed
circuit with the drawer closed. If improper operation is indicated, replace the stop switch.
5. Reconnect all leads removed from components during testing.
6. Reassemble the unit.
7. Reconnect the power supply cord.
8. Run the oven and check all functions.
NOTE: If the stop switch contacts fail in the open position and the door is closed, the cooling fan motor,
stirrer motor and oven light will be activated by RY1.
J STOP SWITCH TEST
K MONITOR SWITCH TEST
1. Disconnect the power supply cord.
2. Open the drawer and keep it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. Before performing this test, make sure that the secondary interlock switch is operating, 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 drawer is open,
the meter should indicate a closed circuit. When the monitor switch actuator is pushed by a screw
driver through the lower latch hole on the front plate of the oven cavity with the drawer 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 and both the monitor switch,
plus fuse will need to be replaced. After testing the monitor switch, reconnect the wire lead to the
monitor switch (COM) terminal and check the continuity of the monitor circuit.
5. Reconnect all leads removed from components during testing.
6. Reassemble the unit.
7. Reconnect the power supply cord.
8. Run the oven and check all functions.
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
1. Disconnect the power supply cord.
2. Open the drawer and keep it open.
3. To discharge 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 drawer open and a closed circuit with the drawer closed. If improper operation
is indicated, replace the secondary interlock switch.
5. Reconnect all leads removed from components during testing.
6. Reassemble the unit.
7. Reconnect the power supply cord.
8. Run the oven and check all functions.
Screw Driver
To Ohmmeter
(WHT) (BLK)
(RED, BLK)
(ORG, BLK)

20
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
M POWER TRANSFORMER TEST
1. Disconnect the power supply cord.
2. Open the drawer and block it open.
3. Discharge high voltage capacitor.
4. 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 82 ohms (+ or - 10%); the resistance of the filament coil should be less than 1
ohm.
5. Reconnect all leads removed from components during testing.
6. Reassemble the unit.
7. Reconnect the power supply cord.
8. Run the oven and check all functions.
CAUTION:
(HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO
MEASURE THE FILAMENT AND HIGH VOLTAGE.)
2. Open the drawer and block it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. If the monitor fuse is blown when the drawer is opened, check the primary interlock switch, secondary
interlock switch and monitor switch according to the "TEST PROCEDURE" for those switches before
replacing the blown monitor fuse.
CAUTION: BEFORE REPLACING A BLOWN MONITOR FUSE,TESTTHE SECONDARY INTERLOCK
SWITCH, STOP 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, "SEE PARTS LIST" Page 34.
5. Reconnect all leads removed from components during testing.
6. Reassemble the unit.
7. Reconnect the power supply cord.
8. Run the oven and check all functions.
L BLOWN MONITOR FUSE TEST
1. Disconnect the power supply cord.