SERVICE MANUAL MODEL MW9107W/WC
SERVICE MANUAL
MODEL
MW9107W/WC
CAUTION: Before servicing the chassis, read the Safety and Precautions section on page 1 of this manual.
SPECIFICATIONS
CONTENTS
POWER SUPPLY................................120V 60Hz AC, 12A SINGLE
PHASE WITH GROUNDING
POWER CONSUMPTION.......................................................1400W
MICROWAVE OUTPUT POWER...........................................1000W
OUTSIDE DIMENSIONS.......................21.2(W) x 16.0(D) x 11.8(H)
CAVITY DIMENSIONS............................13.9(W) x 14.7(D) x 9.0(H)
CAVITY VOLUME...............................................................1.1 CU.FT
NET WEIGHT ...................................................34.2 LBS (APPROX.)
TIMER..........................................................................59 min. 99 sec.
SAFETY AND PRECAUTIONS ...................................................... 1
1. FOR SAFE OPERATION .......................................................... 1
2. FOR SAFE SERVICE PROCEDURES ................................... 1
EXTERNAL VIEW ............................................................................ 2
1. OUTER DIMENSION ................................................................ 2
2. FEATURE DIAGRAM ................................................................ 3
3. CONTROL PANEL .................................................................... 4
INSTALLATION................................................................................. 5
OPERATIONS AND FUNCTIONS ................................................. 6
DISASSEMBLY AND ASSEMBLY ................................................. 7
INTERLOCK MECHANISM AND ADJUSTMENT ....................... 14
TROUBLESHOOTING GUIDE ...................................................... 15
MEASUREMENT AND TEST ....................................................... 19
1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT ....... 19
2. MICROWAVE RADIATION TEST .......................................... 20
3. COMPONENT TEST PROCEDURE ..................................... 21
WIRING DIAGRAM ........................................................................ 22
PRINTED CIRCUIT BOARD .......................................................... 24
1. CIRCUIT CHECK PROCEDURE ........................................... 24
2. P.C.B. CIRCUIT DIAGRAM ..................................................... 29
3. COMPONENT INFORMATION .............................................. 30
4. PRINTED CIRCUIT BOARD ................................................... 31
5. P.C.B. LOCATION NO ............................................................. 32
EXPLODED VIEW AND PARTS LIST ......................................... 33
1. DOOR ASSEMBLY ................................................................. 33
2. CONTROL PANEL ASSEMBLY ............................................ 33
3. TOTAL ASSEMBLY ................................................................ 33
SERVICE PUBLICATION
Note: All the specifications and features are subject to change without notice.
Copyright 2004 Emerson Radio Corp. All rights reserved.
EMERSON RADIO CORP.
Parsippany, NJ 07054
SAFETY AND PRECAUTIONS
CAUTION
This device is to be Serviced only by Properly Qualified Service Personel. Consult the Service Manual for Proper
Service Procedures to Assure Continued Safety Operation and for Precautions to be Taken to Avoid Possible
Exposure to Excessive Microwave Energy.
1. FOR SAFE OPERATION
Damage that allows the microwave energy (that cooks or heats the food) to escape will result in poor cooking and may
cause serious bodily injury to the operator.
IF ANY OF THE FOLLOWING CONDITIONS EXIST, OPERATOR MUST NOT USE THE APPLIANCE.
(Only a trained service personnel should make repairs.)
(1) A broken door hinge.
(2) A broken door viewing screen.
(3) A broken front panel, oven cavity.
(4) A loosened door lock.
(5) A broken door lock.
The door gasket plate and oven cavity surface should be kept clean.
No grease, soil or spatter should be allowed to build up on these surfaces or inside the oven.
DO NOT ATTEMPT TO OPERATE THIS APPLIANCE WITH THE DOOR OPEN.
The microwave oven has concealed switches to make sure the power is turned off when the door is opened.
Do not attempt to defeat them.
DO NOT ATTEMPT TO SERVICE THIS APPLIANCE UNTIL YOU HAVE READ THIS SERVICE MANUAL.
2. FOR SAFE SERVICE PROCEDURES
1. If the oven is operative prior to servicing, a microwave emission check should be performed prior to servicing the
oven.
2. If any certified oven unit is found to servicing, a microwave emission check should be performed prior to servicing the
oven.
(a) inform the manufacturer, importer or assembler,
(b) repair the unit at no cost to the owner,
(c) attempt to ascertain the cause of the excessive leakage,
(d) tell the owner of the unit not to use the unit until the oven has been brought into compliance.
3. If the oven operates with the door open, the service person should tell the user not to operate the oven and contact
the manufacturer and CDRH immediately.
CAUTION
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
CONNECTED. ALL INPUT AND OUTPUT MICROWAVE CONNECTIONS. WAVEGUIDE FLANGES AND
GASKETS MUST BE SECURE. NEVER OPERATE THE DEVICE WITHOUT A MICROWAVE ENERGY
ABSORBING LOAD ATTACHED. NEVER LOOK INTO AN OPEN SAVEGUIDE OR ANTENNA WHILE THE
DEVICE IS ENERGIZED.
1
EXTERNAL VIEW
1. OUTER DIMENSION
2
2. FEATURE DIAGRAM
1. DOOR SEAL
Door seal maintains the microwave within the oven cavity and prevents microwave leakage.
2. DOOR HOOK
When the door is closed, it will automatically lock shut. If door is opened while oven is operating, magnetron tube will
immediately stop operating.
3. DOOR SCREEN
Allows viewing of food. Microwave cannot pass through perforations in screen.
4. SPATTRSHIELD
Protects the microwave outlet from splashes of cooking foods.
5. OVEN LAMP
Automatically turns on during oven operating.
6. SAFETY INTERLOCK SYSTEM
7. CONTROL PANEL
8. GLASS COOKING TRAY
Made of special heat resistant glass. The tray must always be in proper position before operating. Do not cook food
directly on the tray.
9. OVEN FRONT PLATE
10. DOOR OPENING BUTTON
To open the door push the door opening button. When door is closed, it will automatically lock shut. If door is opened
while oven is operating, magnetron tube will immediately stop operating.
11. ROLLER GUIDE
Supports the glass cooling tray.
3
3. CONTROL PANEL
STAGE DEFROST AUTO
ME START
2 WEIGHT TI
1
LOCK NO CUPS OZ Ib
POPCORN
SOUP
MUPPI
N
BAKED
POTATO
PROZEN
PIZZA
DINNER
PIZZA
PRESA
VEGETABLE MORE LESS BEVERAGE
Quick
cook
AUTO DEF.
1
2
3
4
5
6
7
8
9
POW ER
0
STOP/
CLEAR
CLOCK
A START
START
1. Time set pad – Used to set the cooking time and the present time.
2. Display – Cooking time, power level, indicators and present time are displayed.
3. One touch – Used to cook or reheat specific quantities of food.
4. Auto cook – Used to cook or reheat.
5. More – Used to add time to cooking.
6. Less – Used to remove time from cooking.
7. Auto Defrost – Used to defrost foods. (for weight)
8. Power – Used to set power level.
9. Defrost – Used to defrost foods. (for time)
10. Kitchen Timer – Used as minute timer, delay cooking, hold setting after cooking.
11. Clock – Used to set clock.
12. Stop/Clear – Used to stop the oven operation or to delete the cooking data.
13. Start/Speedy cook – Used to start the oven and also used to set a reheat time.
4
INSTALLATION
1. Steady, flat location.
This microwave oven should be set on a steady, flat surface.
2. Leave space behind and side.
All air vents should be kept a clearance. If all vents are covered during operation, the oven may be overheated
and, eventually, cause oven failure.
3. Away from radio, and TV sets
Poor television reception and radio interference may result if the oven is located close to a TV, radio, antenna or
feeder and so on.
4. Away from heating appliances and water taps
Keep the oven away from hot air, steam or splash when choosing a place to position it, or the insulation might be
adversely affected and breakdowns occur.
5. Power supply
• Check your local power source.
This microwave oven requires a current of approximately 12 amperes, 120Volts, 60Hz grounded outlet.
• Power supply cord is about 0.8 meters long.
1. A short power-supply cord is provided to reduce the risks resulting from becoming entangled in or tripping over
a longer cord.
2. Longer cord sets or extension cords are available and may be used if care is exercised in their use.
3. If a long cord or extension cord is used:
1) The marked electrical rating of the cord set or extension cord should be at least as great as the electrical rating of the appliance.
2) The extension cord must be a grounding type 3-wire cord.
3) The longer cord should be arranged so that it will not drape over the counter top or tabletop where it can be
pulled on by children or tripped over unintentionally.
6. Examine the oven after unpacking for any damage such as:
A misaligned door, broken door or a dent in cavity.
If any of the above are visible, DO NOT INSTALL, and notify dealer immediately.
5
OPERATIONS AND FUNCTIONS
1. Connect the main lead to an electrical outlet.
2. After placing the food in a suitable container, open the oven door and put it on the glass tray. The glass tray must always
be in place during cooking.
3. Close the door securely.
4. The oven door can be opened at any time during operation by touching the door release button on the control panel.
The oven will automatically shut off. To restart the oven, close the door and then touch START.
5. Each time a pad is touched, a BEEP will sound to acknowledge the touch.
6. The oven automatically cook on full power unless set to a lower power level.
7. The display will show : 0 when the oven is plugged in.
8. Time clock returns to the present time when the cooking time ends.
9. When the STOP/CLEAR pad is touched during the oven operatiion, the oven stops cooking and all information retained.
To erase all information (except the present time), touch the STOP/CLEAR pad once more. If the oven door is opened
during the oven operation, all information is retained.
10. If the START pad is touched and the oven does not operate, check the area between the door and door seal for obstructions and make sure the door is closed securely. The oven will not start cooking under the door is completely closed or
the program has been reset.
Make sure the oven is properly installed and plugged into the electrical outlet.
Wattage output chart
The power level is set by pressing the POWER pad. The chart shows the display, the power level and the percentage
of power.
Touch POWER pad
Power level(Display)
Approximate Percentage of Power
Once
P-HI
100%
Twice
P-90
90%
3 times
P-80
80%
4 times
P-70
70%
5 times
P-60
60%
6 times
P-50
50%
7 times
P-40
40%
8 times
P-30
30%
9 times
P-20
20%
10 times
P-10
10%
11 times
P-00
0%
6
DISASSEMBLY AND ASSEMBLY
Cautions to be observed when trouble shooting.
Unlike many other appliances, the microwave oven is high-voltage, high-current equipment.
It is completely safety during normal operation.
However, carelessness in servicing the oven can result in an electric shock or possible danger from a short circuit.
You are asked to observe the following precautions carefully.
1. Always remove the power plug from the outlet before servicing.
2. Use an insulated screwdriver and ware rubber gloves when servicing the high voltage side.
3. Discharge the high voltage capacitor before touching any oven components or wiring.
(1) Check the grounding.
Do not operate on a two-wire extension cord.
The microwave oven is designed to be used while grounded.
It is imperative, therefore, to makes sure it is grounded properly
before beginning repair work.
(2) Warning about the electric charge in the high voltage capacitor.
For about 30 seconds after the operation stopped and electric
charge remains in the high voltage capacitor.
When replacing or checking parts, short between oven chassis and
the negative high terminal of the high voltage capacitor by using a
properly insulated screwdriver to discharge.
4. When the 20A fuse is blown due to the operation of the monitor switch;
replace primary interlock switch, secondary interlock switch and interlock monitor switch.
5. After repair or replacement of parts, make sure that the screws are
properly tightened, and all electrical connections are tightened.
6. Do not operate without cabinet.
CAUTION : Service personnel should remove their watches whenever working close to or replacing the magnetron.
WARNING : When servicing the appliance, take a care when touching or replacing high potential parts because of
electrical shock or exposing microvave. These parts are as follows - HV Transformer, Magnetron, HV
Capacitor, HV Diode.
7
1. To remove cabinet
1) Remove three screws on cabinet back.
2) Push the cabinet backward.
2. To remove door assembly
1) Remove two screws which secure the stopper hinge top.
2) Remove the door assembly from top plate of cavity.
3) Reverse the above for reassembly.
NOTE : After replacing the door assembly, perform a check of correct alignment with the hinge and cavity front plate.
8
3. To remove door parts.
A03
A04
A06
A05
A01
A02
A07
A08
REF NO.
A01
A02
A03
A04
A05
A06
A07
A08
PART CODE
3517005900
3512204310
3515202900
3511711300
3517005800
3512301900
3513100700
3515101300
PART NAME
BARRIER-SCREEN *O
FRAME DOOR
STOPPER HINGE *T AS
DOOR PAINTING AS
BARRIER-SCREEN *I
GASKET DOOR
HOOK
SPRING HOOK
DESCRIPTION
PET T0.25
ABS XR-401,H-2938
KOR-121M0A
KOR-1A1G0A
PE T0.1
PP
POM
PW1
(1) Remove the gasket door from door plate.
(2) Remove the barrier screen inner from door plate.
(3) Remove the door frame from door plate.
(4) Remove the stopper hinge top from door plate.
(5) Remove the spring and the hook.
(6) Remove the barrier screen outer from door frame.
(7) Reverse the above steps for reassembly.
9
Q’TY
1
1
1
1
1
1
1
1
REMARK
4. Method to reduce the gap between the door seal and the oven front surface.
(1) To reduce gap located on part ‘A’
• Loosen two screws on stopper hinge top, and then
push the door to contact the door seal to oven front
surface.
• Tighten two screws.
(2) To reduce gap located on part ‘B’
• Loosen two screws on stopper hinge under, and then
push the door to contact the door seal to oven front
surface.
• Tighten two screws.
(3) To reduce gap located on part ‘C’
• Loosen a screw on interlock switch assembly located
top of oven body.
• Draw the interlock switch assembly inward as possible to engage with hook on the door bottom.
• Tighten a screw.
(4) To reduce gap located on part ‘D’
• Loosen a screw on interlock switch assembly located bottom of oven body.
and (4) are same as step (3).
NOTE : A small gap may be acceptable if the microwave leakage does not exceed 4mW/cm2.
10
5. To remove control panel parts.
B03
B04
B02
B01
B05
B06
B07
REF NO.
B01
B02
B03
B04
B05
B06
B07
PART CODE
3518570980
3516722310
3514321900
7122401211
3513702800
441G430171
3516907910
PART NAME
SWITCH MEMBRANE
CONTROL-PANEL
PCB AS
SCREW TAPPING
LEVER DOOR OPEN
BUTTON SPRING
BUTTON DOOR OPEN
DESCRIPTION
KOR-1A8Q0A
ABS AF-345,HFA-700HT
KOR-1A8Q0A
T2S TRS 4X12 MFZN
ABS XR-401 H-2938
SWP DIA 0.7
ABS AF-345,HFA-700HT
Q’TY
1
1
1
4
1
1
1
REMARK
(1) Remove the screw which secure the control panel, push up two snap fits and draw forward the control panel assembly.
(2) Remove the door open lever from the control panel.
(3) Remove four screws which secure the PCB assembly to control panel.
(4) Disconnect membrane tail from the connector of the PCB assembly.
(5) Detach membrane from the control panel.
(6) Remove door open button and button spring from the control panel.
(7) Reverse the above steps for reassembly.
11
6. To remove high voltage capacitor.
1) Remove a screw which secure the grounding ring
terminal of the H.V. diode and the capacitor holder.
2) Remove the H.V. diode from the capacitor holder.
3) Reverse the above steps for reassembly.
◆ High voltage circuit wiring
7. To remove magnetron.
1) Remove a screw which secure the magnetron.
2) Remove the magnetron.
3) Reverse the above steps for reassembly.
NOTE : Never install the magnetron without the metallic gasket plate which is packed with each magnetron to prevent microwave leakage. Whenever repair work is carried out on magnetron, check the microwave leakage.
It shall not exceed 4mW/cm2 for a fully assembled oven with door normally closed.
12
8. To remove wind guide assembly.
1) Remove a screw which secure the wind guide assembly.
2) Draw forward the wind guide assembly.
3) Pull the fan from the motor shaft.
4) Remove two screws which secure the motor shaded pole.
5) Remove the motor shaded pole.
6) Reverse the above steps for reassembly.
9. To remove H.V.transformer.
1) Remove four screws holding the H.V.transformer.
2) Remove the H.V.transformer.
3) Reverse the above steps for reassembly.
13
INTERLOCK MECHANISM AND ADJUSTMENT
The door lock mechanism is a device which has been specially designed to completely eliminate microwave radiation when
the door is opened during operation, and thus to perfectly prevent the danger resulting from the leakage of microwave.
(1) Primary interlock switch
When the door is closed, the hook locks the oven door. If the door is not closed properly, the oven will not operate.
When the door is closed, the hook pushes the button of the microswitch. Then the button of the primary interlock switch
bring it under “ON” condition.
(2) Secondary interlock switch and interlock monitor switch
When the door is closed, the hook pushes the lock lever downward. The lock lever presses the button of the interlock
monitor switch to bring it under “NO” condition and presses the button of the secondary interlock switch to bring it under
“ON” condition.
ADJUSTMENT :
Interlock monitor switch
When the door is closed, the interlock monitor switch should be changed(NO condition) before other switches are closed.
When the door is opened, the interlock monitor switch should be changed(NC condition) after other switches are opened.
(3) Adjustment steps
a) Loosen the two mounting screws.
b) Adjust interlock switch assembly position.
c) Make sure that lock lever moves smoothly after adjustment is completed.
d) Tighten completely two mounting screws.
NOTE :
Microwave emission test should be performed after adjusting interlock mechanism. If the microwave smission exceed
4mW/cm2, readjust interlock mechanism.
14
TROUBLESHOOTING GUIDE
Following the procedure below to check if the oven is defective or not.
1. Check grounding before trouble checking.
2. Be careful of the high voltage circuit.
3. Discharge the high voltage capacitor.
4. When checking the continuity of the switches, fuse or high voltage transformer, disconnect one lead wire from these parts
and check continuity with the AC plug removed. To do otherwise may result in a false reading or damage to your meter.
NOTE : When electric parts are checked, be sure the power cord is not inserted the wall outlet.
Check wire harness, wiring and connected of the terminals and power cord before check the parts listed
below.
(TROUBLE 1) Oven does not operate at all ; any inputs can not be accepted.
CONDITION
CHECK
RESULT
Check continuity of interlock
monitor switch with door closed
Continuity
Fuse blows.
CAUSE
Malfunction of
interlock monitor switch
REMEDY
Replace
NOTE 1
No Continuity
Replace fuse
Check continuity of of primary
interlock switch contact with door
partially open until interlock monitor switch contact close
Check continuity of primary
winding of low voltage transformer
Continuity
0Ω or infinite
Approx.
150~310
(normal)
Normal
Disconnect one side of the lead
wire connected form high voltage transformer to the high voltage capacitor and operate the
unit
Fuse again
blows
15
Shorted contacts of primary
interlock switch.
Defective low
voltage transformer
Defective high
voltage capacitor
Defective high
voltage transformer
Replace
NOTE 1
Replace
Replace
Replace
CONDITION
Outlet has
proper voltage Fuse
does not
blow.
CHECK
RESULT
CAUSE
REMEDY
No
Continuity
Defective magnetron
Replace
Check continuity of magnetron
Check continuity of
power supply cord
No
Continuity
Open power supply cord
Replace
Normal
Defective touch
control circuit
Replace
Malfunction of secondary interlock
switch
Replace
Display do not shown
countdown
NOTE
All these switches must be replaced at the same time, please refer to “Interlock Mechanism And Adjustment”.
(TROUBLE 2) Display shows all figures selected, but oven does not start cooking, even though desired program and
time are set and start pad is tapped.
CONDITION
CHECK
RESULT
CAUSE
REMEDY
Turn table
motor and
oven lamp
do not turn
on
Check continuity of primary interlock switch
No
Continuity
Malfunction of primary interlock
switch
Adjust or
replace
Check continuity of secondary
interlock switch
No
Continuity
Check D.C. voltage being supplied to RELAY (RY2) coil
0V
Defective touch
control circuit
Approx.
15 VDC
Faulty contacts of
RELAY (RY2) or
open relay coil
16
Malfunction of secondary interlock
switch
Adjust or
replace
Replace
Replace
(TROUBLE 3)
CONDITION
No
microwave
oscillation
No microwave oscillation even though fan motor rotates.
CHECK
RESULT
CAUSE
REMEDY
Check continuity of high
voltage capacitor terminals
with wires removed
Continuity
Defective high
voltage transformer
Replace
Check continuity of high voltage
rectifier in forward and backward
direction with DC megger
Continuity in
backward
direction
Defective high
voltage rectifier
Replace
Connect megger leads to magnetron terminal and magnetron
body
Continuity
Defective magnetron
Replace
Defective high
voltage transformer
Replace
0 Ω or ∞
Check resistance of primary and
secondary coil of high voltage
transformer
No
Continuity
Check continuity of magnetron
with wires removed
No
Continuity
Check continuity of filament terminal of high voltage transformer
Defective magnetron
Defective high
voltage transformer
0V
Check D.C. voltage being supplied to RELAY (RY1) coil
Defective touch
control circuit
Approx
15 VDC
17
Faulty
contacts of
RELAY (RY1)
or open
relay coil
Replace
Replace
Replace
Replace
(TROUBLE 4)
The following visual conditions indicate a probable defective touch control circuit or membrane switch
assembly.
1. Incomplete segments
(1) Segments missing
(2) Partical segments missing
(3) Digit flickering other than normal display slight flickering
(4) “ :0” does not display when power is on.
STAGE
1
2
LOCK
NO
DEFROST
WEIGHT TIME
AUTO
START
2. A distinct change in the display are not on when they numbers is the
display.
3. One or more digits in the display are not on when they should be.
CUPS
OZ
lb
4. Display indicates a number different from one touched.
5. Specific numbers (for example 2 or 3) will not display when the panel is touched.
6. Display does not count down or up with time cooking or clock operation.
7. Oven is programable and cooks normally but no display shows.
8. Display obviously jumps in time while counting down.
9. Display counts down noticeably too fast while cooking.
10. Display does not show the time of day when cancel pad is touched.
11. Oven lamp and turntable motor do not stop although cooking is finished. Check if the RELAY 2 contacts close if they are
close, replace touch control circuit.
CONDITION
CHECK
Display does
not show
programming
at all, even if
keyboard is
touched.
Check each pad for
continuity of the membrane
keyboard for the following keyboard check procedure
RESULT
Normal
Abnormal
CAUSE
REMEDY
Malfunction
of touch
control circuit
of control box
sub-assembly
Replace control box subassembly
Malfunction
of the membrane
keyboard
Replace the
membrane
keyboard
NOTE
Before following the particular steps listed above in the trouble shooting guide for the membrane keyboard's,
failure, please check for the continuity of each wire-harness between the membrane keyboard and P.C.B.
assembly.
18
MEASUREMENT AND TEST
1. MEASUREMENT OF THE MICROWAVE POWER OUTPUT
Microwave output power can be checked by indirectly measuring the temperature rise of a certain amount of water
exposed to the microwave as directed below.
PROCEDURE
1. Microwave power output measurement is made with the microwave oven
supplied at rated voltage and operated at its maximum microwave power
setting with a load of 1000±5cc of potable water.
2. The water is contained in a cylindrical borosilicate glass vessel having a
maximum material thickness of 3 mm and an outside diameter of approximately 190 mm.
3. The oven and the empty vessel are at ambient temperature prior to the start
of the test.
The initial temperature of the water is 10±2˚C (50±3.6˚F)
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 shelf, which is in the lowest normal position.
4. Microwave power is switched on.
5. Heating time should be exactly A seconds. (Refer to table as following)
Heating time is measured while the microwave generator is operating at full power.
The filament heat-up time for magnetron is not included.
6. The initial and final temperature of water is selected so that the maximum difference between the ambient and final water
temperature is 5K.
7. The microwave power output P in watts is calculated from the following formula :
P=4187 X ▲T/t
• ▲T is difference between initial and ending temperature.
• It is the heating time.
The power measured should be B (Refer to SPECIFICATIONS)W±10.0%.
CAUTION :
1. Water load should be measured exactly to 1 liter.
2. Input power voltage should be exactly specified voltage(Refer to SPECIFICATIONS).
3. Ambient temperature should be 20±2˚C(68±3.6˚F)
• Heating time for power output:
A(second)
70
64
60
56
52
49
47
44
42
40
38
B(W)
600
650
700
750
800
850
900
950
1000
1050
1100
19
2. MICROWAVE RADIATION TEST
CAUTION :
1. Make sure to check the microwave leakage before and after repair of adjustment.
2. Always start measuring of an unknown field to assure safety for operating personnel from microwave energy.
3. Do not place your hands into any suspected microwave radiation field unless the safe density level is known.
4. Care should be taken not to place the eyes in direct line with the source of microwave energy.
5. Slowly approach the unit under test until the radiometer reads an appreciable microwave leakage from the unit
under the test.
PROCEDURES
1. Prepare Microwave Energy Survey Meter, 600cc glass
beaker, and glass thermometer 100˚C(212˚F).
2. Pour 275cc±15cc of tap water initially at 20±5˚C(68±9˚F) in
the 600cc glass beaker with an inside diameter of approx.
95mm(3.5in.).
3. Place it at the center of the tray and set it in a cavity.
4. Close the door and operate the oven.
5. Measure the leakage by using Microwave Energy Survey
Meter with dual ranges, set to 2450MHz.
1) Measured radiation leakage must not exceed the value
prescribed below. Leakage for a fully assembled oven with
door normally closed must be less than 4mW/cm2.
2) When measuring the leakage, always use the 5cm(2in.)
space cone with probe. Hold the probe perpendicular to
the cabinet and door. Place the space cone of the probe
on the door, cabinet, door seem, door viewing screen, the
exhaust air vents and the suction air vents.
3) Measuring should be in a counter-clockwise direction at a
rate of 1 in./sec. If the leakage of the cabinet door seem is
unknown, move the probe more slowly.
4) When measuring near a corner of the door, keep the probe
perpendicular to the areas making sure the probe end at the base of the cone does not get closer than 2 in. from any
metal. If it does not, erroneous reading may result.
20
3. COMPONENT TEST PROCEDURE
• High voltage is present at the high voltage terminal of the high voltage transformer during any cooking cycle.
• It is neither necessary nor advisable to attempt measurement of the high voltage.
• Before touching any oven components or wiring, always unplug the oven from its power source and discharge the
capacitor.
1. High voltage transformer
(1) Remove connections from the transformer terminals and check continuity.
(2) Normal readings should be as follows:
Secondary winding
Approx. 110Ω±10%
Filament winding Approx. 0Ω
Primary winding Approx. 1Ω
2. High voltage capacitor
(1) Check continuity of capacitor with meter on the highest OHM scale.
(2) A normal capacitor will show continuity for a short time, and then indicate 10MΩ once the capacitor is charged.
(3) A shorted capacitor will show continuous continuity.
(4) An open capacitor will show constant 10MΩ.
(5) Resistance between each terminal and chassis should be infinite.
3. High voltage diode
(1) Isolate the diode from the circuit by disconnecting the leads.
(2) With the ohmmeter set on the highest resistance scale measure the resistance across the diode terminals.
Reverse the meter leads and again observe the resistance reading.
Meter with 6V, 9V or higher voltage batteries should be used to check the front-back resistance of the diode,
otherwise an infinite resistance may be read in both directions. A normal diode’s resistance will be infinite in one
direction and several hundred KΩ in the other direction.
4. Magnetron
For complete magnetron diagnosis, refer to “Measurement of the Microwave Power Output”.
Continuity checks can only indicate and open filament or a shorted magnetron.
To diagnose for an open filament or a shorted magnetron.
(1) Isolate magnetron from the circuit by disconnecting the leads.
(2) A continuity check across magnetron filament terminals should indicate 0.1Ω or less.
(3) A continuity check between each filament terminal and magnetron case should read open.
5. Fuse
If the fuse in the primary and monitor switch circuit is blown when the door is opened, check the primary and
monitor switch before replacing the blown fuse.
In case the fuse is blown by an improper switch operation, replace the defective switch and fuse at the same time.
Replace just the fuse if the switches operate normally.
21
1) MW9107W
22
2) MW9107WC
23
PRINTED CIRCUIT BOARD
1. CIRCUIT CHECK PROCEDURE
1. Low Voltage Transformer (DMR-602P) check
• The low voltage transformer is located on the P.C.B.
• Measuring condition: input voltage : 120V/Frequency : 60Hz
1
5
4
Terminal Voltage
4-7
LOAD
AC 12.6 V
NO LOAD
AC 14.7 V
3
2
NOTE :
Secondary side voltage of the low voltage transformer changes in proportion to fluctuation of power source voltage
NOTE :
The allowable tolerance of the secondary voltage is within ± 5% of norminal voltage.
2. Voltage check
• Key check point
NO
CHECK POINT
REMARK
1
IC 1 PIN 7,41,42
-5 VDC
2
IC 1 PIN 11
GND
3
IC 1 PIN 23
4.3V
T:16.7ms(60Hz)
0V
4
IC 1 PIN 8 OR 9
5V
T:250ns(4MHz)
0V
• Check method
NO
MEASURE POINT
1
MP1
2
MP2
WAVE FORM
REMEDY
REMARK
DC -5V±0.25V
Replace VL1, EC1
NO LOAD
DC -12V±2.0V
Replace EC2, D12, 13, 14
NO LOAD
NOTE :
Each measure point must be measured with GND points.
24
Bottom View
25
3. Display problems
NO
CAUSE
MEASUREMENT
1
Defective Display
Refer to “The display trouble
shooting data”bellow.
i
d
c
b
h
14
a
Replace P.C.B. assembly
Display layout
(Top View)
eo
f
G1
REMEDY
1
e
g
RESULT
fo
G2
G3
G4
G5
- The display trouble shooting data
TROUBLE
DISPLAY NAME & PIN NO.
MICOM OUTPUT IN PIN NO.
STAGE 1, LOCK DON”T COME ON.
Digit 1 (G1), 10
31
STAGE 2, NO don’t come on.
Digit 2 (G2), 11
32
WEIGHT DEFROST, CUPS don’t come on.
Digit 3 (G3), 14
30
TIME DEFROST doesn’t come on.
Digit 4 (G4), 12
33
AUTO START, g don’t come on.
Digit 5 (G5), 13
29
SEGMENT “a” doesn’t come on from G1 to G5.
SEGMENT a, 7
20
SEGMENT “b” doesn’t come on from G1 to G5.
SEGMENT b, 6
19
SEGMENT “c” doesn’t come on from G1 to G5.
SEGMENT c, 5
18
SEGMENT “d” doesn’t come on from G1 to G5.
SEGMENT d, 4
17
SEGMENT “e” doesn’t come on from G1 to G5.
SEGMENT e, 3
16
SEGMENT “f” doesn’t come on from G1 to G5.
SEGMENT f, 2
14
SEGMENT “g” doesn’t come on from G1 to G5.
SEGMENT g, 1
13
LOCK, NO, CUPS, g don’t come on.
LOWER BAR h, 9
15
STAGE 1, STAGE 2, TIME DEFROST, WEIGHT
UPPER BAR i, 8
21
DEFROST, AUTO START don’t come on.
4. When there is no microwave oscillation.
1) When touching START pad, oven lamp does not turn on.
Fan motor and turnatable motor do not rotate, but cook indicator in display comes on.
* Cause : RELAY 2 does not operate.
+12V DC
IC1
D9
1N4002A
Q11
KRC106M
Q12 KRC
106M
RY2
G5B-12V
40
FAN RY
TRAY RY
A
26
- Check method
POINT
STATE
A
RELAY 2 ON
GND
RELAY 2 OFF
+12VDC
2) When touching START pad, oven lamp turns on.
Fan motor and turntable rotate and cook indicator in display comes on.
* Cause : RELAY 1 does not operate.
IC1
D8
1N4002A
Q11
KRC106M
A
39
MGT RY
B
- Check method
POINT
A
B
RELAY 1 ON
+5VDC
GND
RELAY 1 OFF
GND
+12VDC
STATE
5. When the door is opened during operation, the count down timer does not stop.
V1
B
CN1(D.O.M)
YW396-02V
D6
1N4148M
R15
2
A
1
C1
473
R16
10K
1K
37
DOM
C2
104
R17
1K
IC1
- Check method
POINT
A
B
1) DOOR OPEN
OPEN
5VDC
2) DOOR CLOSED
CLOSE
GND
STATE
CHECK NO
1
METHOD
REMEDY
Check the stage(ON,OFF) of the secondary interlock switch by
resistance measurement.
27
Replace secondary interlock
switch.
6. When the digital clock does not operate properly.
LVT1
D12
1N148M
R22
10K
A
R21
4.7K
POINT
A
ZD2
C5
5.1V
104
WAVE FORM
4.3V
T : 20ms(50Hz)
16.67ms(60Hz)
GND
T
❈ If clock does not keep exact time, you must check resistor R15,16, zener diodeZD1.
28
IC1
23
EXINT
CN1(D.O.M)
INSERT ONLY KOR-121QOD
29
POP
CORN
BAKED
POTATO
FRESH
VEGETABLE
SOUP
2. PCB CIRCUIT DIAGRAM
3. COMPONENT INFORMATION
1) Transistor
Q9
Emitter
Collector
Base
2) Diode and Zener Diode
DIODE
Cathode (K)
ANODE (A)
D1-D6, D8-D14
ZENER
DIODE
Cathode (K)
ANODE (A)
ZD1,ZD2
3) Digital Transistor
* Internal circuit
Q1-Q8
Q11-Q13
R1
Collector
BASE
R2
Emitter
Emitter
Collector
Base
30
RESISTOR
R1
R2
KRC106M
4.7K
47K
KRA110M
4.7K
-
TYPE
4. PRINTED CIRCUIT BOARD
31
5. P.C.B. LOCATION NO.
NO.
PART NAME
REF NO.
SPECIFICATION
PART CODE
Q'TY
1
RESISTOR
R11, R15, R17, R24
1K, 1/6W, 5%
RD-AZ102J-
4
2
RESISTOR
R13, R16, R22
10K, 1/6W, 5%
RD-AZ103J-
3
3
RESISTOR
R21
4.7K, 1/6W, 5%
RD-AZ472J-
1
4
RESISTOR
R10, R18, R19, R20
100K, 1/6W, 5%
RD-AZ104J-
4
5
RESISTOR
R14
1M, 1/6W, 5%
RD-AZ105J-
1
6
RESISTOR
R12
100, 1/6W, 5%
RD-AZ101J-
1
7
RESISTOR
R23
51, 1/4W, 5%
RD-4Z510J-
1
8
RESISTOR
R1, 2, 3, 4, 5, 6, 7, 8, 9
330, 1/4W, 5%
RD-4Z331J-
9
9
RARRAY
RA1
RGLD6X104J
RA-87X104J-
1
10
DIODE
D1-D6, D10, D11, D12
1N4148M
DZN4148M--
9
11
DIODE
D8, D9, D13, D14
1N4002A
DZN4002A--
4
12
DIODE ZENER
ZD2
5.1VB, 1/2W
DZTZ3R9B--
1
13
DIODE ZENER
ZD1
3.9VB, 1/2W
DZTZ3R9B--
1
14
TRANS POWER
LVT1
DMR-602P
5EPU035406
1
15
CAPACITOR ELECTRO
EC1
100MF 16V RSS
CEXF1C101V
1
16
CAPACITOR ELECTRO
EC2
1000MF 25V RSS
CEXF1E102V
1
17
P. C. B. BARE
M152
M152
3514315400
1
18
LED DISPLAY
DP1
DDG611Q
DDDG611Q00
1
19
CARRAY
CA1
F6 102Z
CN6XB-102M
1
20
TRANSISTOR
Q9
KTA1270Y
TZTA1270Y-
1
21
TRANSISTOR
Q1-Q5
KRA110M
TZRA110M--
5
22
TRANSISTOR
Q6-Q8, Q11-Q13
KRC106M
TZRC106M--
6
23
CONNECTOR WAFER
CN1
YW396-02V
3519150520
1
24
CONNECTOR WAFER
CN3
YM396-05AV
3519150510
1
25
CONNECTOR WAFER
CN2
FCZ254-11
441M367160
1
26
BUZZER
BZ1
BM-20K
3515600100
1
27
REGULATOR
VL1
MC7805C
1CPMC7805C
1
28
CAPACITOR CERAMICQ
C1
50V 473 AXIAL
CCZF1H473Z
1
29
CAPACITOR CERAMIC
C2, C3, C4, C5, C6
50V 104 AXIAL
CCZF1H104Z
5
30
RESONATOR
CR1
KBR-4.0MKSTF
5PKBR40MKS
1
31
SW RELAY
RY1
G5J-1-TP-M12V
5SC0101108
1
32
SW RELAY
RY2
G5B-DC12V
5SC0101110
1
33
IC MICOM
IC1
HD404054A47S
147S121MQ0
1
32
EXPLODED VIEW AND PARTS LIST
1. DOOR ASSEMBLY
Refer to Disassembly and assembly.
2. CONTROL PANEL ASSEMBLY
Refer to Disassembly and assembly.
3. TOTAL ASSEMBLY
1) MW9107W
33
1) MW9107W
REF NO
A00
B00
F01
F02
F03
F04
F05
F06
F07
F08
F09
F10
F11
F12
F13
F14
F15
F16
F17
F18
F19
F20
F21
F22
F23
F24
F25
F26
F27
F28
F29
F30
F31
F32
F33
F34
F35
F36
F37
F38
F39
F40
F41
F42
F43
F44
F45
PART CODE
3511711210
PKCPSWL900
3510805500
3516004100
3516110400
7122401211
7122401211
7112401011
35113TAN0H
7112401011
3518605800
7121402511
3963821610
3512517000
3511800300
3518002900
3516004000
7122400400
3513003200
3518302101
3518400400
3518118600
3516003700
3510312400
7112401011
3512100900
7272400811
3515202800
3512716800
4415A17352
4415A66600
3518571000
4415A66910
3513702600
3513811700
3513601500
7121400611
3966820200
3518905400
3513003410
7272400811
3511406200
3517400620
3514701501
3512519300
441CD35011
PART NAME
DOOR AS
CONTROL PANEL AS
CABINET AS
SPECIAL SCREW
CAVITY AS
SCREW TAPPING
SCREW TAPPING
SCREW TAPPING
CORD POWER AS
SCREW TAPPING
FUSE
HOLDER FUSE
SCREW TAPPING
MOTOR SHADED POLE
GUIDE WIND
FAN
MAGNETRON
SPECIAL SCREW
SCREW TAPPING
HOLDER HV CAPACITOR
CAPACITOR HV
DIODE HV
TRANS HV
SPECIAL SCREW
BASE
SCREW TAPPING
FOOT
SCREW TAPTITE
STOPPER HINGE *U AS
HARNESS MAIN
SW MICRO
SW MICRO
SWITCH PUSH
SW MICRO
LEVER LOCK
LOCK
LAMP
SCREW TAPPING
MOTOR SYNCRO
THERMOSTAT
HOLDER THERMOSTAT
SCREW TAPTITE
COVER WAVE GUIDE
COUPLER
ROLLER
GUIDE ROLLER
TRAY
34
DESCRIPTION
KOR-1A8Q0A
KOR-1A8Q0A
KOR-1A1G0A LOUVER
T1 TRS LR4 POLE 4*10 MFZN
KOR-1A1G0A
T2S TRS 4*12 MFZN
T2S TRS 4*12 MFZN
T1 TRS 4*10 MFZN
3X16AWG 60X60 120-RTML
T1 TRS 4*10 MFZN
65TS 125V 20A
NYLON66
T2S PAN 4X25 MFZN
120V 60HZ MW10XA-M01
PP
PP+30%GLASS
2M218J(MF) P
T2 BOLT FLANGE 5X12 DACRO
T2S TRS 4X8 MFZN
SECC T0.6
2100VAC 0.95UF #187
HVR-1X-3AB 12KV #187
DW-R11A0-1BT
TT3 HEX 4X8 FLG MFZN
SBHG T0.8
T1TRS 4*10 MFZN
PP DASF-130
TT3 TRS 4X8 MFZN
SCP-1 T2.5
KOR-1A1G0A
VP-533A-OF SPNO #187 200G
VP-532A-OF SPNO #187 200G
MP 101C
VP-531A-OF/SZM-V16-FA-61
POM
POM
BL 125V 25W T25 C5A H187
T2S PAN 4X6 MFZN
120V 2W GM-16-12F17
OFF:90 ON:60 H #187 NB
PP(BK)
TT3 TRS 4X8 MFZN
HEATPROOF PP
XAREC
TEFLON
PP
GLASS
Q'TY
1
1
1
3
1
1
2
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
4
1
5
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
1
1
2) MW9107WC
35
2) MW9107WC
REF NO
A00
B00
F01
F02
F03
F04
F05
F06
F07
F08
F09
F10
F11
F12
F13
F14
F15
F16
F17
F18
F19
F20
F21
F22
F23
F24
F25
F26
F27
F28
F29
F30
F31
F32
F33
F34
F35
F36
F37
F38
F39
F40
F41
F42
F43
F44
PART CODE
3511711210
PKCPSWL900
3510805500
7112401011
3516110400
7122401211
7122401211
7272400811
35113X5W0L
7112401011
3518606600
7121402511
3963821600
3512517000
3511800300
3518002900
3516004000
7122400811
3513003200
3518303100
3518400400
3518113800
3516003700
3510312400
7112401011
3512100900
7272400811
3515202800
3512716810
4415A17352
4415A66910
3518571000
4415A66910
3513702600
3513811700
3513601500
7121400611
3966820200
3518905400
3513003410
7272400811
3511406200
3517400620
3514701501
3512519300
441CD35011
PART NAME
DOOR AS
CONTROL-PANEL AS
CABINET AS
SCRW TAPPING
CAVITY AS
SCREW TAPPING
SCREW TAPPING
SCREW TAPTITE
CORD POWER AS
SCREW TAPPING
NOISE FILTER
SCREW TAPPING
MOTOR SHADED POLE
GUIDE WIND
FAN
MAGNETRON
SPECIAL SCREW
SCREW TAPTITE
HOLDER HV CAPACITOR
CAPACITIR HV
DIODE HV
TRANS HV
SPECIAL SCREW
BASE
SCREW TAPPING
FOOT
SCREW TAPTITE
STOPPER HINGE *U AS
HARNESS MAIN
SW MICRO
SW MICRO
SWITCH PUSH
SW MICRO
LEVER LOCK
LOCK
LAMP
SCREW TAPPING
MOTOR SYNCRO
THERMOSTAT
HOLDER THERMOSTAT
SCREW TAPTITE
COVER WAVE GUIDE
COUPLER
ROLLER
GUIDE ROLLER
TRAY
36
DESCRIPTION
KOR-1A8Q0A
KOR-1A8Q0A
KOR-1A1G0A LOUVER
T1 TRS 4*10 MFZN
KOR-1A1G0A
T2S TRS 4*12 MFZN
T2S TRS 4*12 MFZN
TT3 TRS 4*8 MFZN
3*16AWG 80*80 120-RTML
T1 TRS 4*10 MFZN
DWLF-M17
T2S TRS 4*25 MFZN
120V 21W OEM-10DWX1-A07
PP
PP+30%GLASS
2M218J(F)P 6CF
T2 BOLT FLANGE 5*12 DACRO
T2S TRS 4*8 MFZN
SECC T0.6
2100VAC 0.98ßfi #187
HR-1X-3AB 12KV #187
DY-N95A0-16T
TT3 HEX 4*8 FLG MFZN
SBHG T0.7
T1 TRS 4*10 MFZN
PP DASF-130
TT3 TRS 4*8 MFZN
KOR-121M0A
KOR-1A1G1A
VP-533A-OF SPNO #187 200G
VP-531A-OF/SZM-V16-FA-61
MP101C
VP-531A-OF/SZM-V16-FA-61
POM
POM
BL 125V 25W T25 C5A H187
T2S PAN 4*16 MFZN
120V 2W GM-16-12F17
OFF:90 ON:60 H #187 NB
PP(BK)
TT3 TRS 4*8 MFZN
HEATPROOF PP
XAREC
TEFRON
PP 5113MF6 A353R
GLASS
Q'TY
1
1
1
3
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
4
1
5
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
3
1
1
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising