Svan SVMW821EIB User manual

SVMW821EIB
SERVICE MANUAL

This document is published to be used for after sales service only. The content are subject
to change without prior notice.
In interest of user safety the appliance should be restored to its original condition and only
parts identical to those should be applied.
November, 2017

CONTENTS
CAUTIONS
INSTALLATIONS
SERVICE INFORMATION
TOOLS AND MEASURING INSTRUMENTS
MICROWAVE LEAKAGE TEST
MEASUREMENT OF MICROWAVE POWER OUTPUT
DISASSEMBLY AND ADJUSTMENT
1
2
3
3
3
5
5
INTERLOCK CONTINUITY TEST
Assembly Removal
oltage Transformer Removal
Assembly Removal
And Diode Removal
Air Guide Assembly Removal
11. Turntable Motor Removal
1Assembly Removal
1 . Interlock System
1. Primary Interlock Switch Test
2. Secondary Interlock Switch Test
3. Monitor Switch Test
5
6
6
6
7
7
7
8
8
9
9
9
9
. Capacitor
COMPONENT TEST PROCEDURE
TROUBLE SHOOTING
10
14
1. Trim Assembly Removal 5
2. Outer Case Removal
3. Power Supply Cord Removal
4. Control Panel Assembly Removal
5. Door
6. High V
7. Orifice
8. H.V
9.
10. Magnetron Removal
2. PCB
3
6
6
7

• DO NOT operate on a 2-wire extension cord during
repair and use.
• NEVER TOUCH any oven components or wiring during
operation.
• BEFORE TOUCHING any parts of the oven, always
remove the power plug from the outlet.
• For about 30 seconds after the oven stops, an electric
charge remains in the high voltage capacitor. When
replacing or checking, you must discharge the high
voltage capacitor by shorting across the two terminals
with an insulated screwdriver.
• Remove your watches whenever working close to or
replacing the Magnetron.
• NEVER operate the oven with no load.
•NEVER injure the door seal and front plate of the oven
cavity.
• NEVER put iron tools on the magnetron.
• NEVER put anything into the latch hole and the
interlock switches area.
• Proper operation of the microwave oven requires that
the magnetron be assembled to the waveguide and
cavity. Never operate the magnetron unless it is
properly installed.
• Be sure that the magnetron gasket is properly
installed around the dome of the tube whenever
installing the magnetron.
CAUTIONS
Unlike other appliances, the microwave oven is
high-voltage and high-current equipment.
Though it is free from danger in ordinary use,
extreme care should be taken during repair.
THE OVEN IS TO BE SERVICED ONLY
BY PROPERLY QUALIFIED SERVICE
PERSONNEL.
MICROWAVE RADIATION
Personnel should not be exposed to the
microwave energy which may radiate from the
magnetron or other microwave generating
device if it is improperly used or connection.
All input and output microwave connections,
waveguide, flange and gasket must be secure
never operate the device without a microwave
energy absorbing load attached.
Never look into an open waveguide or antenna
while the device is energized.
ANTENNA
COOLING FIN
MAGNETRON
CHASSIS GROUND
FILAMENT
TERMINALS
MAGNETRON
GASKET
1

INSTALLATIONS
INSTALLING EARTHING INSTRUCTIONS
This microwave oven is designed to be used in a fully
earthed condition.
It is imperative, therefore, to make sure it is properly
earthed before servicing
WARNING-
THIS APPLIANCE
MUST BE EARTHED
IMPORTANT
As the colors of the wires in the mains lead of this
appliance may not correspond with the colored
markings identifying the terminals in your plug,
proceed as follows.
The wire which is colored green-and-yellow must be
connected to the terminal in the plug which is marked
with the letter E or by the earth symbol ( ) or
colored green or green-and-yellow .
The wire which is colored blue must be connected to
the terminal in the plug which is marked with the letter
N or colored black .
The wire which is colored brown must be connected
to the terminal in the plug which is marked with the
letter L or colored red.
BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.
The wires in this mains lead are colored in
accordance with the following code:
Green-and-yellow: Earth
Blue: Neutral
Brown: Live
2
1. Empty the microwave oven and clean inside it with
a soft, damp cloth. Check for damage such as
misaligned door, damage around the door or dents
inside the cavity or on the exterior.
2. This oven is intended for built-in use only. it's not
3. The appliance is fitted with a plug and must only
4. The mains voltage must correspond to be voltage
5. The socket must be installed and connecting cable
6. Adaters, multi-way strips and extension leads must
intended for counter-top use or for use inside a
cupboard.
be connected to a properly installed earthed socket.
specified on the rating plate.
must only be replaced by a qualified electrician. If
not be used. Overloading can result ain a risk of fire.
the plug is no longer to accessible following insta-
present on the installation side with a contact gap
llation, an all-pole disconnecting device must be
of at least 3mm.
600
560+8
(45)
+3
min
500 X

CAUTIONS
• Be sure to check microwave leakage prior to
servicing the oven if the oven is operative prior to
servicing.
• The service personnel should inform the
manufacture importer, or assembler of any
certified oven unit found to have a microwave
emission level in excess of 5 mW/cm 2and should
repair any unit found to have excessive emission levels
at no cost to the owner and should ascertain the cause
of the excessive leakage. The service personnel
should instruct the owner not to use the unit until the
oven has been brought into compliance.
• If the oven operates with the door open, the service
personnel should:
- Tell the user not to operate the oven.
- Contact the manufacturer.
• The service personnel should check all surface and
vent openings for microwave leakage.
• Check for microwave leakage after every servicing.
The power density of the microwave radiation leakage
emitted by the microwave oven should not exceed
4 mW/cm2. Always start measuring of an unknown field
to assure safety for operating personnel from radiation
leakage.
MEASURING MICROWAVE ENERGY
LEAKAGE
• Pour 275±15cc of 20±5°C(68±9°F) water in a beaker
which is graduated to 600 cc, and place the beaker
on the center of the turntable.
• Set the energy leakage monitor to 2450 MHz and
use it following the manufacturer's recommended
test procedure to assure correct result.
• When measuring the leakage, always use the 2-
inch (5cm) spacer supplied with the probe.
• Operate the oven at its maximum output.
• Measure the microwave radiation using and
electromagnetic radiation monitor by holding the
probe perpendicular to the surface being measured
Move probe along shaded area
Probe scanning speed
Less than 2.5 cm/sec
( 1in/sec)
TOOLS AND MEASURING INSTRUMENTS
MICROWAVE LEAKAGE TEST
NECESSARY TOOLS
Tools normally used for TV servicing are sufficient.
Standard tools are listed below.
• Diagonal pliers
• Long nose pliers
• Phillips screwdriver
• Flat blade screwdriver
• Wrench (size 5mm)
• Nutdriver (size 5mm)
• Adjustable wrench
• Soldering iron
• Solder
• Vinyl insulation tape
• Polishing cloth
NECESSARY MEASURING INSTRUMENTS
• TESTER(VOLTS-DC, AC., Ohmmeter)
• Microwave survey meter
- Holaday HI-1500
HI-1501
- Narda 8100
8200
• Inch scale
• 600 cc non conductive material beaker (glass or plastic),
inside diameter: approx. 8.5 cm(31/2 in.)
• Cylindrical and made of borosilicate glass vessel.
max. thickness: 3 mm
outside diameter: approx. 190mm
height: approx. 90mm
• Glass thermometer: 100°C or 212°F (1 deg scale)
SERVICE INFORMATION
3

MEASUREMENT WITH OUTER CASE
REMOVED
When you replace the magnetron, measure for
microwave energy leakage before the outer case is
installed and after all necessary components are
replaced or adjusted.
Special care should be taken in measuring the
following parts. (Circled area of below Fig.)
- Around the magnetron
- The waveguide
MEASUREMENT WITH A FULLY
ASSEMBLED OVEN
After all components, including the outer case, are fully
assembled, measure for microwave energy leakage
around the door viewing window, the exhaust opening,
and air inlet openings.
Microwave energy leakage must not exceed the values
prescribed below.
NOTE: Leakage with the outer case removedless than
5 mW/cm2.sq. Leakage for a fully assembled
oven (Before the latch switch (primary) is
interrupted) with the door in a slightly opened
position-less than 2 mW/cm2.sq.
NOTES WHEN MEASURING
Do not exceed meter full scale deflection.
The test probe must be removed no faster than
1 inch/sec (2.5 cm/sec) along the shaded area,
otherwise a false reading may result.
The test probe must be held with the grip portion of the
handle.
A false reading may result if the operator's hand is
between the handle and the probe.
When testing near a corner of the door, keep the probe
perpendicular to the surface making sure the probe
horizontally along the oven surface, this may possibly
cause probe damage.
RECORD KEEPING AND NOTIFICATION
AFTER MEASUREMENT
After adjustment and repair of any microwave energy
interruption or microwave energy blocking device,
record the measured values for future reference. Also
enter the information on the service invoice.
The microwave energy leakage should not be more
than 4 mW/cm2.sq. after determining that all parts are
in good condition, functioning properly and genuine
replacement parts which are listed in this manual have
been used.
At least once a year, have the electromagnetic energy
leakage monitor checked for calibration by its
manufacturer.
WARNING : AVOID CONTACTING ANY
HIGH VOLTAGE PARTS
4
•
•
•
•
•
•
•
•
•
•

1) Disconnect the power supply cord from the outlet.
2) Remove the screws from the rear and along side
edges of the case.
The outer case must be moved backward to be
1) Remove the outer case.
2) Disconnect two terminals, and remove one screw of
the earth terminal.
MEASUREMENT OF MICROWAVE POWER OUTPUT
• Microwave power output measurement is made with
the microwave oven supplied at its rated voltage and
operated at its maximum microwave power setting with
a load of (1000±5) g of potable water.
• The water is contained in a cylindrical borosilicate glass
vessel having a maximum material thickness of 3 mm
and an outside diameter of approximately 190mm.
• The oven and the empty vessel are at ambient
temperature prior to the start of the test.
• The initial temperature (T1) of the water is (10±2)°C. It
is measured immediately before the water is added to
the vessel. After addition of the water to the vessel,
the load is immediately placed on the center of the
turntable which is in thd lowest position and the
microwave power switched on.
• The time T for the temperature of the water to rise by a
value ∆ T of (10±2)°K is measured, where T is the time
in seconds and ∆T is the temperature rise. The initial
and final water temperatures are selected so that the
maximum difference between the final water
temperature and the ambient temperature is 5°K.
4187 x (∆T) + 0.55 X (T2- T0) X M
T
• T 2 : Temperature after heating
• T 0 : Temperature of bowl
• M: Weight of bowl
is measured while the microwave generator is
operating at full power. Magnetron filament heat-up
time is not included. (about 3 sec)
• The water is stirred to equalize temperature throughout
the vessel, prior to measuring the final water
temperature.
• Stirring devices and measuring instruments are
selected in order to minimize addition or removal of
heat.
WATER LOAD
TURNTABLE
P =
• The microwave power output P in watts is calculated
from the following formula :
NOTES:
For simple tests of micromave power output,
it by heating one litre water for one minute,
minimum temperature rise should be 6 C
°
conduct
DISASSEMBLY AND ADJUSTMENT
CAUTION: DISCHARGE THE HIGH VOLTAGE
CAPACITOR BEFORE SERVICING
(refer to page 1)
lifted off.
5
2. OUTER CASE REMOVAL
3. POWER SUPPLY CORD REMOVAL
1) Open the door, remove the Screw B from the installa-
1. TRIM ASSEMBLY REMOVAL
Installation Hole
Screw B
tion hole.
3) Remove the screws on both side. Then remove the
2) Pull the Microwave oven out.
trim Assembly out of cavity.

REMOVAL
1) Discharge the high voltage capacitor.
2) Disconnect the leadwire from magnetron, high voltage
transformer, and capacitor.
3) Remove the screw holding the high voltage
transformer to the baseplate.
1) Discharge the high voltage capacitor.
2) Disconnect the leadwire from fan motor, noise filter
and high voltage capacitor.
3) Remove the two screws holding the orifice
oven cavity and remove the high voltage
earth screw.
4) Remove the screw of the capacitor bracket.
5) Remove the two screws holding the fan motor ASS’Y
to the Orifice
to the diode
ASSEMBLY REMOVAL
ASS’Y
.
ASS’Y
1) Discharge the high voltage capacitor.
2) Disconnect the leadwire from fan motor, noise filter
and high voltage capacitor.
cavity
and remove the high voltage diode
earth screw.
4) Remove the screw holding the high voltage capacitor
bracket.
3) Remove the screw holding the Orifice
the oven
to
ASS’Y
1) Disconnect the leadwire from the PCB SUB ASS’Y.
2) Remove the screws for the earth and securing the
control panel.
3) Lift control panel ASS’Y from the oven by the tab
unhooked.
1) Open the door.
CAUTION : Be careful not to damage Door C
by screwdriver.
3) Lift up and pull the door.
NOTE:
1. After replacing the door, be sure to check that the
primary switch, monitor switch, and secondary switch
operate normally.
2. After replacing the door, check for microwave energy
leakage with a survey meter. Microwave energy must
be below the limit of 5 mW/cm2. (with a 275 ml water
load)
3. When mounting the door assembly to the oven
assembly, be sure to adjust the door assembly parallel
to the chassis. Also adjust so the door has no play
between the inner door surface and oven frame
assembly. If the door assembly is not mounted
properly, microwaves may leak from the clearance
between the door and the oven.
to the Cavity Ass'y.
2) Remove two screws holding the Hinge
Remove door Assembly
6
Control Panel Assembly
Door Assembly
②
③
②
③
H.V. Transformer
H.V. Capacitor
H.V. Diode
4. CONTROL PANEL ASSEMBLY REMOVAL
5. DOOR ASSEMBLY REMOVAL
6. HIGH VOLTAGE TRANSFORMER
7.
8. H.V. CAPACITOR AND DIODE REMOVAL
ORIFICE

1) Disconnect the leadwire from lamp, A.C Relay and
monitor resistor and magnetron.
2) Remove the screw to the cavity.
1) Disconnect the leadwire from the high voltage
transformer and high voltage capacitor.
2) Remove the air
3) Carefully remove the mounting screws holding the
magnetron and the waveguide.
4) Remove the magnetron until the tube is
clear from the waveguide.
1) Remove the glass tray.
2) Remove the pulley shaft VERY CAREFULLY
3) Lay the unit down on its back.
4) Remove the turntable motor cover.
The turntable base cover is easily removed by
pinching the six parts with a wire cutting.
5) Disconnect the leadwire from the turntable motor
terminals.
6) Remove the screw securing the turntable motor to
the oven cavity ASS’Y
7) After rep the motor, rotate the removed
turntable motor cover.
8) Fit the turntable motor cover’s projecting part to the
base plate slit.
Waveguide
Magnetron
Gasket
Magnetron
Dome
Waveguide
Bracket
Magnetron
guide
lacing
.
NOTE:
1. Remove the wire lead from the turntable motor
VERY CAREFULLY.
2. Be sure to grasp the connector, not the wires, when
removing
NOTE:
1. When removing the magnetron, make sure its
dome does not hit any adjacent parts, or it may be
damaged.
magnetron.
2. When replacing the magnetron, be sure to install
the magnetron gasket in the correct position and
3. After replacing the magnetron, check for microwave
leakage with a survey meter around the
magnetron. Microwave energy must be below the
limit of 5 mW/cm2. (With a 275 ml. water load).
Make sure that gasket is rigidly attached to the
To prevent microwave leakage, tighten the
mounting screws properly, making sure t
here is no gap
between the waveguide and the magnetron.
2
IDE ASSEMBLY REMOVAL
AL
11. TURNTABLE MOTOR
7
REMOVAL9. AIR GU
10. MAGNETRON REMOV
be sure that the gasket is in good condition.

1) Remove the control panel assembly from the
cavity.
2) Remove screws which hold the PCB to
control panel.
3) Disconnect the flat cable from the PCB
take off the PCB .
1) INTERLOCK MECHANISM
The door lock mechanism is a device which has
been specially designed to eliminate completely
microwave activity when the door is opened during
cooking and thus to prevent the danger resulting
from the microwave leakage.
2) MOUNTING OF THE PRIMARY/MONITOR/
SECONDARY SWITCHES TO THE LATCH
BOARD
3) INSTALLATION AND ADJUSTMENT OF THE
LATCH BOARD TO THE OVEN ASSEMBLY
• Mount the latch board to the oven assembly.
• Adjust the latch board in the arrow direction so that
oven door will not have any play in it when the door
is closed.
• Tighten the mounting screw.
• Check for play in the door by pushing the door
release button. Door movement should be less
than 0.5 mm. (1/64 inch)
Don't push the door release button while making
adjustment. Make sure that the latch moves
smoothly after adjustment are completed and that
the screws are tight. Make sure the primary, monitor,
and secondary switches operate properly by
following the continuity test procedure.
ADJUSTMENT
DIRECTION
CAUTION: CHECK THE CORRECT POSITION
MAGNETRON
H.V. TRANSFORMER
PRIMARY
H.V. CAPACITOR
H.V.
DIODE
FIG. 1
the
and
PRIMARY
SWITCH
MONITOR
SWITCH
SECONDARY
SWITCH
1
1 INTERLOCK SYSTEM
8
2. PCB ASSEMBLY REMOVAL
3.
PRIMARY
SWITCH
PRIMARY
SWITCH
SECONDARY
SWITCH
MONITOR
SWITCH
MOTOR
Fig.1 For Common Built-In Model
Fig.2 For Electric Door Control Built-In Model

When the door release button is depressed slowly
with the door closed, an audible click should be
heard at the same time or successively at
intervals. When the button is released slowly, the
latches should activate the switches with an
audible click .
If the latches do not activate the switches when
the door is closed, the switches should be a
adjusted in accordance with the adjustment
procedure. Disconnect the wire lead from the
primary switch. Connect the ohmmeter leads to
the common (COM) and normally open (NO)
terminal of the switch. The meter should indicate
an open circuit in the door open condition.
When the door is closed, the meter should
indicate a closed circuit.
When the primary switch operation is abnormal,
make the necessary adjustment or replace the
switch only with the same type of switch.
Disconnect the wire lead from the secondary
switch.
Connect the ohmmeter leads to the common
(COM) and normally open (NO) terminals of the
switch. The meter should indicate a open circuit in
the door open condition. When the door is closed,
meter should indicate an closed circuit. When the
secondary switch operation is abnormal, make the
necessary adjustment or replace the switch only
with the same type of switch.
. MONITOR SWITCH TEST
Disconnect the wire lead from the monitor switch.
Connect the ohmmeter leads to the common
(COM) and normally closed (NC) terminals of the
switch. The meter should indicate closed circuit in
the door open condition. When the door is closed,
meter should indicate an open circuit. When the
monitor switch operation is abnormal, replace with
the same type of switch.
NOTE: After repairing the door or the interlock
system, it is necessary to do this continuity
test before operating the oven.
WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION
EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS.
COMPONENTS TEST PROCEDURE RESULTS
SWITCHES Check for continuity of the Door Door
(Wire leads removed) switch with an Ohm-meter open closed
Primary
Switch
Monitor
Switch
NOTE : After checking for the continuity of switches, make sure that are
correctly connected.
COM
NO
COM
NC
COM
NO
INTERLOCK CONTINUITY TEST
Secondary
Switch
TYPE NO. KW3A FOR SWITCHS
Type No.KW3A
Type No.KW3A
Type No.KW3A
1 . PRIMARY INTERLOCK SWITCH TEST
2 . SECONDARY INTERLOCK SWITCH TEST
3
9

CAUTIONS
1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE
OUTER CASE FROM THE UNIT. PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH
VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE
HIGH VOLTAGE TRANSFORMER. (SEE PAGE 1)
2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER
OF WATER IN CONTAINER) IN THE OVEN.
COMPONENTS TEST PROCEDURE RESULTS
HIGH VOLTAGE
TRANSFORMER
(Wire leads removed)
MAGNETRON
(Wire leads removed)
1. Measure the resistance.
(Ohm-meter scale: Rx1)
•Primary winding
•Secondary winding
•Filament winding
2. Measure the resistance.
(Ohm-meter scale: Rx1000)
•Primary winding to ground
•Filament winding to ground
1. Measure the resistance.
(Ohm-meter scale: Rx1)
•Filament terminal
2. Measure the resistance.
(Ohm-meter scale: Rx1000)
•Filament to chassis
Approx.: 1.4 ohm
Approx.: 90 ohm
Less than: 1 ohm
Normal: Infinite
Normal: Infinite
Normal: Less than 1 ohm
Normal: Infinite
COMPONENT TEST PROCEDURE
PRIMARY
TERMINAL
SECONDARY
WINDING
FILAMENT
WINDING
TERMINAL
10

COMPONENTS TEST PROCEDURE RESULTS
HIGH VOLTAGE
CAPACITOR
HIGH VOLTAGE
DIODE
NOTE :
Some inexpensive meters
may indicate infinite
resistance in both direction.
Measure the resistance.
(Ohm-meter scale: Rx1000)
•Terminal to terminal.
Measure the resistance.
(Ohm-meter scale: Rx1000)
•Terminal to case.
Measure the continuity (Forward).
(Ohm-meter scale: Rx10000)
Measure the continuity (Reverse).
(Ohm-meter scale: Rx10000)
Normal: Momentarily indicates
several ohms, and then
gradually returns to
Normal: ∞
Normal: Continuity.
Abnormal: ∞
Normal: ∞
Abnormal: Continuity.
NOTE: When testing the magnetron, be sure to install the magnetron gasket
in the correct position and be sure that the gasket is in good condition.
Antenna
Gasket
Chassis
Filament
10M ohms.
*
*
11

FUSE Check for continuity of the fuse with an
multi-meter.
NOTE: If the fuse is blown, check the primary, the secondary, and the monitor switches,
H.V.D. and H.V.C. before replacing the fuse.
If the fuse is blown by improper switch operation replace the defective switch and the
fuse at the same time. Replace just the fuse if the switches operate normally.
Normal Abnormal
HEATER ELEMENT
(Wire leads removed.)
Measure the resistance.
(Multi-meter scale: Rx1)
Measure the resistance with 500V-100M ohm
insulation resistance meter.
NOTE: Make sure heater is fully cooled when tested.
Normal:
*Grill heater
Approx. 38 ohm
(at 20 ~ 30°C)
Normal: more than 0.5 Mohm
temperature
specified
temperature
Above
COMPONENTS TEST PROCEDURE RESULTS
Below specified
THERMAL CUT-OUT
12

FAN MOTOR
(Wire leads removed)
TURNTABLE
MOTOR
(Wire leads removed)
Measure the resistance.
(Ohm-meter scale: R x 1000)
NOTE : • A MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS
SERVICED FOR ANY REASON.
• MAKE SURE THE WIRE LEADS ARE IN THE CORRECT POSITION.
• WHEN REMOVING THE WIRE LEADS FROM THE PARTS, BE SURE TO GRASP THE
CONNECTOR, NOT THE WIRES.
1 3 5
Measure the resistance.
(Ohm-meter scale: R x 1)
Normal:
Abnormal: ∞ or several Ω
00~5001
RELAY 2, RELAY 3
OF P.C.B.
(Wire leads removed.)
Note: Relay
Relay 1: Fan motor
Turntable motor
Oven lamp
Relay 2: Microwave
Relay 3: Grill
Relay 2
Relay 1
Relay 3
Cooking Start OFF
Ω
Normal: Approx.100~200K
Abnormal: ∞ or several Ω
Ω
L.V.Transformer of P.C.B
(Refer to schemetic diagram)
Check for P.C.B. connector.
Disconnect the 3 pin
connector from P.C.B.
*
Normal Abnormal
COMPONENTS TEST PROCEDURE RESULTS
13

WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF
THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE
MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL.
1. Check grounding before checking for trouble.
2. Be careful of the high voltage circuit.
3. Discharge the high voltage capacitor. (See page 1)
4. When checking the continuity of the switches or of the high voltage transformer, disconnect one lead wire
from these parts and then check continuity with the AC plug removed. To do otherwise may result in a
false reading or damage to your meter.
5. Do not touch any part of the circuitry on the digital programmer circuit since static electric discharge may
damage this control panel.
Always touch yourself ground while working on this panel to discharge any static charge built up in your
body.
Microwave oven
does not work.
Inserting many plug into one
plug outlet and using
them at the same time
(causes overloading).
Microwave oven plug is not
inserted tightly.
Output power is too low. Low AC input voltage.
Food temperature is too low.
Using metallic ware and
allowing it to touch the oven
wall.
Sparks occurring.
Inconsistent intensity of
microwave by their
characteristics.
1. Wrap the thinner part with
aluminum foil.
2. Use plastic wrap or lid.
3. Stir once or twice while cooking
soup, cocoa or milk, etc.
Uneven cooking.
Ceramic ware trimmed in
gold or silver powder is used.
Avoid using other electrical
appliances when you use the
microwave oven.
Insert microwave oven plug
securely.
Use the microwave oven at
adequate line voltage.
This may not be a defect.
It is possible that the food
should be cooked for a
longer time period.
Do not use metallic ware for
cooking except where noted
in the cooking guide.
Do not use any type of
cookware with metallic
trimming.
Excessive weight on tray or
improperly balanced.
Distribute food evenly. Cook
smaller portions and,or use
lighter weight cookware.
Turntable drags or makes
noise.
TROUBLE SHOOTING
CAUTIONS
CONDITION CAUSE REMEDY
14

1. No input can be
programmed. Continuity.
No continuity.
Defective PCB
assembly.
Replace PCB
assembly.
Check the conn-
ection between
membrane key
assembly and
PCB assembly.
Loose
connection.
Connect them
tightly.
2. Some inputs
cannot be
programmed.
Everything works
as specified.
Still have trouble.
Defective key
membrane
assembly.
Replace key
membrane
assembly.
Replace key
membrane
assembly and
check operation.
3. Display shows a
number or figure
different from one
touched.
4. Random
programming
when touching
other pads.
5. Display is fixed
at some figure
and can not
accept any
input.
Defective PCB
assembly.
Replace PCB
assembly.
1. Incomplete segments.
• Segment missing.
• Partial segment missing.
• Digit flickering (NOTE: Slight flickering is normal.)
2. Colon does not turn on or blink.
3. A distinct change in the brightness of one or more numbers in display.
4. One or more digits in the display are not lighting.
5. Display indicates a number different from one touched, for example, key in 5 and 3 appears in the display.
6. Specific numbers (for example 7 or 9) will not display when key pad is touched.
7. Display does not count down with time blinking or up with clock operation.
8. Display obviously jumps in time while counting down.
9. Display counts down too fast while cooking.
10. Each indicator light does not turn on after setting cooking cycle.
11. Display time of day does not reappear when cooking is finished.
12. Beep sound is not heard when correct key is touched.
(TROUBLE 1) The following visual conditions indicate a probable defective control circuit.
CONDITION CHECK RESULT CAUSE REMEDY
15

1. Fuse blows. Continuity.
Malfunction of the
monitor switch.
Check continuity
of monitor
switch (with
door closed).
Check continuity
of primary
switch (with
door opened).
No continuity.
Disconnect one
side of the wire
lead connected
from transformer
to the high
voltage
capacitor and
operate the unit.
No continuity.
Continuity.
Shorted contact at
the primary switch.
Fuse blows again
Normal.
Defective high
voltage capacitor.
Replace high
voltage capacitor.
Defective high volt-
age transformer.
Replace high volt-
age transformer.
Replace fuse
(TROUBLE 2) Oven does not operate at all ; Display window does not display any figures and
no input is accepted.
NOTE : All these switches must be replaced at the same time. Refer to page ,
CONDITION CHECK RESULT CAUSE REMEDY
Replace primary
and monitor
switches.
Replace primary
and monitor
switches.
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8 9
2. Fuse does not
blow. No continuity.
Continuity.
Check continuity
of power supply
cord.
Defective power
supply cord.
Replace power
supply cord.
Defective grill
thermostat.
Replace grill
thermostat.
Check continuity
of grill thermo-
stat.
No continuity.

(TROUBLE 3) Display shows all figures set, but oven does not start cooking while
desired program times are set and START pad is touched.
(TROUBLE 4) Oven seems to be operation but output power is low.
CONDITION CHECK RESULT CAUSE REMEDY
1.Setting time does
not count down
when touching
START pad.
2. Fan motor or
oven lamp
do not turn
on.
No continuity.
continuity.
No continuity.
Continuity.
Check the con-
nection between
connector and
P.C.B assembly.
Defective
secondary switch.
Replace
secondary switch.
Defective P.C.B
assembly.
Replace P.C.B
assembly.
Check continuity
of secondary
switch (with
door closed).
Check fan motor.
Check oven lamp.
Abnormal.
Abnormal.
Normal.
Defective fan
motor.
Defective oven
lamp.
Replace fan
motor.
Replace oven
lamp.
Loose connection. Connection then
tightly.
CONDITION CHECK RESULT CAUSE REMEDY
Output is low. Lower than 90% of
rating voltage.
Normal.
Normal.
Abnormal.
Abnormal.
Measure the
output power.
Disconnect the
wire leads from
relay 2 and check
on and off time
with multitester.
Defective P.C.B
assembly.
Replace P.C.B
assembly.
Decrease in power
source voltage
with load.
Suggest customer
contact local
electric power
utility co. or
qualified
electrician.
Check the
power source
voltage.
Defective
magnetron.
Replace
magnetron.
NOTE: Refer to Page 5 for measuring of microwave power output.
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