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MICROWAVE OVEN
SERVICE MANUAL
MODEL: EXV 1711W/
EXV 1711B/
EXV 1711BS
CAUTION
BEFORE SERVICING THE UNIT, READ THE
SAFETY PRECAUTIONS IN THIS MANUAL.
CAUTION
SAFETY PRECAUTIONS
PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE EXPOSURE
TO EXCESSIVE MICROWAVE ENERGY
a. Do not operate or allow the oven to be operated with the door open.
b. Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary; (1) Interlock operation, (2) proper door closing, (3) seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and latches, (5) evidence of dropping or abuse.
c. Before turning on microwave power for any service test or inspection within the microwave generating compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and connections.
d. Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the oven is released to the owner.
e. A Microwave leakage check to verify compliance with the Federal Performance
Standard should be performed on each oven prior to release to the owner.
•
Proper operation of the microwave ovens requires that the magnetron be assembled to the wave guide 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.
•
Routine service safety procedures should be exercised at all times.
•
Untrained personnel should not attempt service without a thorough review of the test procedures and safety information contained in this manual.
FOREWORD
Read this Manual carefully. Failure to adhere to or observe the information in this Manual may result in exposing yourself to the Microwave Energy normally contained within the oven cavity.
TABLE OF CONTENTS
(Page)
SAFETY PRECAUTIONS .........................................................................................................
Inside front page
SPECIFICATIONS ..........................................................................................................................................
1-1
CAUTIONS .....................................................................................................................................................
2-1
INSTALLATIONS ............................................................................................................................................
3-1
OPERATING INSTRUCTIONS.......................................................................................................................
4-1
CONTROL PANEL .................................................................................................................................
4-1
CONTROL PANEL INSTRUCTIONS .....................................................................................................
4-2
OVERALL CIRCUIT DIAGRAM ......................................................................................................................
5-1
SCHEMATIC DIAGRAM.........................................................................................................................
5-1
MATRIX CIRCUIT FOR TOUCH KEY BOARD ......................................................................................
5-2
GENERAL INFORMATION FOR SERVICE ...................................................................................................
6-1
GENERAL PRECAUTIONS IN USE ......................................................................................................
6-1
TRIAL OPERATION ...............................................................................................................................
6-1
FEATURES AND SPECIFICATIONS FEATURES.................................................................................
6-1
SERVICE INFORMATION .............................................................................................................................
7-1
PRECAUTIONS AND REPAIR SERVICE TIPS .....................................................................................
7-1
MICROWAVE LEAKAGE TEST .............................................................................................................
7-2
POWER OUTPUT MEASUREMENT .....................................................................................................
7-3
DISASSEMBLY INSTRUCTIONS ..........................................................................................................
7-4
INTERLOCK SYSTEM .......................................................................................................................... 7-12
INTERLOCK CONTINUITY TEST .......................................................................................................... 7-14
TEST AND CHECKOUT PROCEDURES AND TROUBLE SHOOTING................................................ 7-15
A. TEST PROCEDURES................................................................................................................ 7-15
B. CHECKOUT PROCEDURES..................................................................................................... 7-18
C. TROUBLE SHOOTING .............................................................................................................. 7-21
EXPLODED VIEW ..........................................................................................................................................
8-1
REPLACEMENT PARTS LIST ...............................................................................................................
8-8
SCHEMATIC DIAGRAM OF PCB .......................................................................................................... 8-14
PRINTED CIRCUIT BOARD .................................................................................................................. 8-15
PCB PARTS LIST................................................................................................................................... 8-16
Rated Power Consumption
Microwave Output
Frequency
Power Supply
Rated Current
Magnetron Cooling
Rectification
Door Sealing
Safety Devices
Magnetron
High Voltage Capacitor
High Voltage Diode
Cook top Lamp
Cavity Lamp
Timer
Tray
Overall Dimensions
Effective Capacity of Oven Cavity
Accessories
SPECIFICATIONS
1,500W maximum (Microwave oven only)
1000W (IEC 60705)
Adjustable 100W through 1000W, 10 steps
2,450 MHz
+
50 MHz
120 VAC, 60 Hz
13 Amp. (Microwave oven+Cook top lamps+Ventilation fan)
Forced Air Cooling
Rectification Voltage Double Half-Wave
Choke System
Magnetron Thermal Fuse:
Open at 109°C
+
4°C
Oven Cavity Thermostat:
Open at 110°C
+
5°C
Fuse(20A)
Primary Interlock Switch
Secondary Interlock Switch
Interlock Monitor
2M248J
Capacitor: 1.0µF, 2.1 KV AC
Diode; 350mA, 9.0 KV
125 V, 30 W or 40 W
125 V, 30 W
Digital, up to 99 mim. 99 sec. (in each cooking stage)
Tempered Safety Glass
29 15/16
”
(W)x16 7/16
”
(D)x15 1/2
”
(H)
1.7 Cu.ft.
Owner’s Manual & Cooking Guide, Installation Manual,
Exhaust Adapter, Exhaust Damper, Mounting Kit and Two
Filters, Rotating Ring Assembly, Metal Rack.
1-1
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.
• 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.
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.
• 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.
ANTENNA
Gasket
COOLING FIN
FILAMENT
TERMINALS
MAGNETRON
MAGNETRON
CHASSIS GROUND
• Remove your watches whenever working close to or replacing the Magnetron.
• DO NOT touch any parts of the control panel circuit. A resulting static electric discharge may damage this
P.C.B.
• 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.
THE OVEN IS TO BE SERVICED ONLY
BY PROPERLY QUALIFIED SERVICE
PERSONNEL.
2-1
INSTALLATIONS
BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.
PRECAUTIONS ON INSTALLATION
A. Plug the power supply cord into a 120V AC, 60Hz, single-phase power source with a capacity of 15A or 20A.
B. Avoid placing the unit in a location where there is direct heat or splashing water.
C. Install the unit on the mounting plate firmly.
D. Place the unit as far away as possible from TV, radio, etc. to prevent interference.
GROUNDING INSTRUCTIONS
For personal safety, this appliance must be fully grounded at all times.
In the event of an electrical short circuit, grounding reduces the risk of electrical shock.
The plug must be plugged into an outlet that is properly installed and grounded.
CAUTION
This unit is equipped with a 3-prong plug for your safety. If the wall outlet is a grounded 3-hole type, the unit will be grounded automatically.
Plug with Ground
Prong
Properly Polarized and Grounded
Outlet
WARNING
Improper use of the grounding plug can result in a risk of electric shock.
Do not, under any circumstances, cut or remove the third ground prong from the power cord plug.
3-1
CONTROL PANEL
OPERATING INSTRUCTIONS
1
2
3
7
8
10
11
13
16
17
19
20
MORE LESS CLOCK HELP
One Touch Control
POPCORN POTATO BEVERAGE
PIZZA REHEAT COOK
1
4
7
POWER
LEVEL
2
5
8
0
3
6
9
TIME
COOK
STOP/
CLEAR
START Ez On
CUSTOM
SET
CUSTOM
COOK
HOLD
WARM
LIGHT
TIMER
AUTO
DEFROST
KITCHEN
TIMER
TURNTABLE
On/Off
VENT
Hi/Low/Off
LIGHT
Hi/Low/Off
9
12
14
15
18
21
4
5
6
4-1
CONTROL PANEL INSTRUCTIONS
1. DISPLAY: The display includes a clock and indicators to tell you time of day, cooking time settings, and cooking functions selected.
14. HOLD WARM: Press this pad to keep hot, cooked foods safely warm in your microwave oven for up to 99 minutes
99 seconds.
2. MORE: Press this pad to add ten seconds of cooking time each time you press it.
15. AUTO DEFROST: Press this pad to select food type and defrost food by weight.
3. LESS: Press this pad to subtract ten seconds of cooking time each time you press it.
16. CUSTOM COOK: Press this pad to recall one cooking instruction previously programmed into memory.
4. CLOCK(TIME OF DAY): Press this pad to enter the time of day.
17. LIGHT TIMER: Press this pad to set the light timer.
5. HELP: Press this pad to learn how to use each oven function.
18. KITCHEN TIMER: Press this pad to set the kitchen timer.
6. ONE TOUCH CONTROL: Press these keys let you cook foods easily.
19. TURNTABLE ON/OFF: Press this pad to turn off the turntable. OFF will appear in the display.
7. NUMBER: Press number pads to enter cooking time, power level, quantities, or weights.
20. VENT HI/LOW/OFF: Press this pad to turn the fan on or off.
8. POWER LEVEL: Press this pad to select a cooking power level.
9. TIME COOK: Press this pad followed by Numper Pads to set a cooking time.
21. LIGHT HI/LOW/OFF: Press this pad to turn on the cooktop/countertop light.
10. STOP/CLEAR: Press this pad to stop the oven or to clear all entries.
11. START: Press this pad to start a function. If you open the door after oven begins to cook, START again.
12. EZ ON: Press this pad to cook for 30 seconds at 100% power level.
13. CUSTOM SET: Press this pad to change the oven’s default settings for sound, clock, display speed, defrost weight, and demo mode operations.
4-2
OVERALL CIRCUIT DIAGRAM
SCHEMATIC DIAGRAM
5-1
MODEL
B
A
C
MATRIX CIRCUIT FOR TOUCH KEY BOARD
N.C
1
N.C
2
N.C
3 4 5 6 7
POPCORN
AUTO
COOK
AUTO
REHEAT
AUTO
DEFROST
HOLD
WARM
8
9
10
STOP/
CLEAR
START
VENT
H/L/OFF
LIGHT
H/L/OFF
EZ ON
CUSTOM
SET
CUSTOM
COOK
TIME
COOK
POWER
LEVEL
MORE
LIGHT
TIMER
KITCHEN
TIMER
TURNTABLE
ON/OFF
HELP
CLOCK LESS
11
1 2 3
4 5
POTATO
PIZZA
BEVERAGE
12
6 7 8 9 0 N.C
N.C
N.C
13
5-2
GENERAL INFORMATION FOR SERVICE
GENERAL PRECAUTIONS IN USE
A. Never operate the unit when it is empty.
Operating the oven with no load may shorten the life of the magnetron. Whenever cooking dry foods
(dried fish, bread, etc.) or a small amount of food, be sure to put a glass of water into the cooking compartment. The glass turntable may become hot after operating, be careful when touching it.
B. Aluminum foil should be avoided because it will disrupt cooking and may cause arcing. However, small pieces may be used to cover some parts of food to slow the cooking. Any aluminum foil used should never be closer than 2.5 cm to any side wall of the oven.
TRIAL OPERATION
After installation, the following sequences and results should be checked carefully.
A. Put a container filled with water (about 1 liter) into the oven, and close the door tightly.
B. Set cooking time for 10 minutes by touching “1” and then “0” three times. “1, 0, 0, 0” appears in the display window.
C. Touch the START key.
Make sure the cavity light comes on. The unit will begin cooking and the display window will show the time counting down by seconds.
D. After about 5 minutes, make sure the primary interlock switch, the secondary interlock switch and the interlock monitor switch operate properly by opening and closing the door several times. Touch the START key each time the door is closed.
E. Continue operating the unit. Four long beep sound signal is heard when the time is up. The unit will shut off automatically.
F. Confirm the water is hot.
G. Finally, measure the output power according to
“POWER OUTPUT MEASUREMENT” on page 7-3.
FEATURES AND SPECIFICATIONS
FEATURES
A. The safety systems incorporated in this model are:
(1) Primary interlock switch
(2) Secondary interlock switch
(3) Interlock monitor switch
(4) Choke system
(5) Magnetron thermal fuse
(6) Oven cavity thermostat
(Note: This thermostat located on the oven cavity will open and stop the unit from operation only if a high temperature is reached, such as, a fire created by overcooking food.)
B. Any one of 10 power output levels ranging 100W to
1000W can be selected by the touch control and electronic computer system.
6-1
SERVICE INFORMATION
PRECAUTIONS AND REPAIR SERVICE TIPS
PRELIMINARY
A. SINCE NEARLY 2,100 VOLTS EXISTS IN SOME
CIRCUITS OF THIS UNIT REPAIRS SHOULD BE
CARRIED OUT WITH GREAT CARE.
The filament leads of magnetron carry High
Voltage with respect to ground. Extreme caution must be exercised. Never plug the unit into a power source to determine which component is defective in high voltage section.
B. TO AVOID POSSIBLE EXPOSURE TO
MICROWAVE ENERGY LEAKAGE, THE
FOLLOWING PRECAUTIONS MUST BE TAKEN
BEFORE SERVICING.
(1) Before the power is applied:
(a) Make sure the primary interlock switch, the secondary interlock switch and the interlock monitor switch operate properly by opening and closing the door several by opening and closing the door several times.
(b) Make sure the perforated screen and the dielectric choke of the door are correctly and firmly mounted.
(2) After power is applied:
(a) Make sure the interlock switch mechanism is operating properly by opening and closing the door.
(b) Check microwave energy leakage must bebelow the limit of 5 mW/cm 2.
(All service adjustments should be made for minimum microwave energy leakage readings).
(3) Do not operate the unit until it is completely repaired, if any of the following conditions exist.
The unit must not be operated.
(a) The door does not close firmly.
(b) The hinge is broken.
(c) The door seal is damaged.
(d) The door is bent or warped, or there is any other visible damage on the unit that may cause microwave energy leakage.
NOTE: Always keep the seal clean.
(e) Make sure that there are no defective parts in the interlock mechanism.
(f) Make sure that there are no detective parts in the microwave generating and transmission assembly (especially waveguide).
(4) The following items should be checked after the unit is repaired:
(a) The interlock monitor switch is connected correctly and firmly.
(b) The magnetron gasket is properly positioned and mounted.
(c) The waveguide and the oven cavity are intact.
(no microwave energy leakage)
(d) The door can be properly closed and the safety switches work properly.
(e) The unit must stop when the door is opened or the time is up.
The unit must not be operated with any of the above components removed or by-passed.
7-1
MICROWAVE LEAKAGE TEST
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 2
and 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 and CDRH
(Center for Devices and Radiological Health) immediately.
NOTE: Address on CDRH
Office of Compliance(HFZ-312)
Center for Devices and Radiological
Healthe 1390, Piccard Drive,
Rockville. MD 20850
• 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/cm
2
. Always start measuring of an unknown field to assure safety for operating personnel from radiation leakage.
EQUIPMENT
• TESTER (VOLTS-DC, AC, Ohmmeter)
• Microwave survey meter
- Holaday HI-1500
HI-1501
- Narda 8100
8200
• 600 cc non conductive material beaker (glass or plastic), inside diameter: approx. 8.5 cm (3
1/2 in.)
• Glass thermometer: 100°C or 212°F (1 deg scale)
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 2,450 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. ( 1 in/sec)
7-2
MEASUREMENT WITH THE OUTER CASE
REMOVED
(1) 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.
- Around the magnetron
- The waveguide
WARNING: AVOID CONTACTING ANY HIGH
VOLTAGE PARTS.
MEASUREMENT WITH A FULLY
ASSEMBLED OVEN
(1) After all components, including the outer panels, are fully assembled, measure for microwave energy leakage around the door viewing window, the exhaust opening and air inlet openings.
(2) Microwave energy leakage must not exceed the values prescribed below.
NOTES:
Leakage with the outer panels removed - less than 5 mW/cm 2.
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/cm 2.
NOTE WHEN MEASURING
(1) Do not exceed meter full scale deflection.
(2) The test probe must be removed no faster than
1 inch/sec (2.5cm/sec) along the shaded area, otherwise a false reading may result.
(3) 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.
(4) 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
(1) 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.
(2) Should the microwave energy leakage not be more than 2 mW/cm
2 after determining that all parts are in good condition, functioning properly and genuine replacement parts which are listed in this manual have been used.
(3) At least once a year, have the electromagnetic energy leakage monitor checked for calibration by its manufacturer.
POWER OUTPUT MEASUREMENT
(1) 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.
(2) The water is contained in a cylindrical borosilicate glass vessel having a maximum material thickness of
1/8
” (
3 mm) and an outside diameter of approximately 7.6
” (
190mm).
(3) The oven and the empty vessel are at ambient temperature prior to the start of the test.
(4) The initial temperature (T1) of the water is (10±2)°C
(50°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 turntable which is in the lowest position and the microwave power switched on.
(5) 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.
(6) The microwave power output P in watts is calculated from the following formula :
P =
4187 x (
∆
T)
T is measured while the microwave generator is operating at full power. Magnetron filament heat-up time is not included. (about 3 sec)
(7) The water is stirred to equalize temperature throughout the vessel, prior to measuring the final water temperature.
(8) Stirring devices and measuring instruments are selected in order to minimize addition or removal of heat.
WATER LOAD
TURNTABLE
7-3
DISASSEMBLY INSTRUCTIONS
IMPORTANT NOTES:
UNIT MUST BE DISCONNECTED FROM ELEC-
TRICAL OUTLET WHEN MAKING REPAIRS, RE-
PLACEMENTS, ADJUSTMENTS AND CONTIN-
UITY CHECKS. WAIT AT LEAST ONE MINUTE,
UNTIL THE HIGH VOLTAGE CAPACITOR IN THE
HIGH VOLTAGE POWER SUPPLY HAS FULLY
DISCHARGED.
THE CAPACITOR SHOULD BE DISCHARGED BY
USING INSULATED WIRE - I.E. TEST PROBE
CONNECTED TO 10K-OHM RESISTOR IN SERIES
TO GROUND.
WHEN RECONNECTING THE WIRE LEADS TO
ANY PART, MAKE SURE THE WIRING CONNE-
CTIONS AND LEAD COLORS ARE CORRECTLY
MATCHED ACCORDING TO THE OVERALL CIR-
CUIT DIAGRAM. (ESPECIALLY SWITCHES AND
HIGH VOLTAGE CIRCUIT.)
A. REMOVING POWER AND CONTROL
CIRCUIT BOARD (Figures 1, 2 and 3)
(1) Remove a screw securing the control panel assembly to the oven cavity.
(2) Remove the control panel with pushing it upward.
(3) Remove the three connectors (CN1, CN2) and wire leads (Relay2) from the circuit board.
Control Panel
Screw
(4) Remove 3 screws securing the circuit board.
Circuit Board
Figure 2
(5) Remove the FPC connector from the terminal socket following “HOW TO REMOVE THE FPC
CONNECTOR” on the next page.
(6) Remove the circuit board from the control bracket carefully.
Control Bracket
(CN2)
Power
Transformer
(CN2)
Relay 2
(Relay 2)
FPC Connector(S1)
Circuit Board
(CN1)
Figure 1
Figure 3
7-4
HOW TO REMOVE THE F.P.C. CONNECTOR
Follow the steps below as illustrated in Figures 4 and 5 to remove the F.P.C. connector.
(1) Hold the edges of the plastic fastener with thumb and forefinger.
(Figure 4)
(2) Lift up the lever of the plastic fastener from the terminal socket by lightly pressing the lever end with forefinger.
(Figure 5)
(3) Remove the F.P.C. connector from the terminal socket.
Plastic fastener
HOW TO INSERT THE F.P.C. CONNECTOR
Follow the steps below as illustrated in Figures 6 and 7 to insert the F.P.C. connector.
(1) Insert the F.P.C. connector into the terminal socket securely with the fingers.
(2) Hold the plastic fastener with thumb and forefinger of the other hand, and push it slowly into the terminal socket. (Figure 6)
NOTE: When reconnecting the F.P.C connector make sure that the holes on the F.P.C. connector are properly engaged with the hooks on the plastic fastener
(3) Lock the level of the plastic fastener into the hook of the terminal socket securely by releasing the fingers.
(Figure 7)
Holes
Plastic fastener
Hook
F.P.C.
Connector
Terminal
socket
Figure 4
Holes
Plastic fastener
Hook
F.P.C.
Connector
Figure 6
Terminal
socket
Plastic fastener
F.P.C.
Connector
Figure 5
Terminal
socket
F.P.C.
Connector
Terminal
socket
Figure 7
7-5
B. REMOVING THE OUT CASE(Figure 8)
(1) Remove the vent grille by removing two screws securing it to the out case.
(2) Remove two screws securing it to the air duct.
(3) Remove the mounting plate by turning the screws
(1 or 2 screws) securing it to the out case.
(4) Remove two screws on the left central edge and one screws on the right central edge of Base plate. Remove the Mount, All from the out case by removing one screw securing it to the out case.
(5) Remove the outcase with disconnecting power cord connector.
Mount,All
Vent Grille
Door
Figure 8
Controller
(3 screws)
(1 or 2 screws)
Mounting
Plate
Out Case
7-6
C REMOVING THE DOOR INTERLOCK
SWITCHES (Figures 9,10)
(1) Disconnect the wire leads from the interlock switches.
(2) Remove two screws securing the Latch Board.
(3) Make necessary replacements and check microwave energy leakage according to
“ADJUSTMENT PROCEDURE” on page 7-12.
Latch Board
Secondary Interlock Switch
WH(from H.V.Transformer)
YL(from Fan Motor)
WH(from Power Cord)
WH(from cooktop lamp)
Monitor Interlock Switch
WH(from H.V.Transformer)
RD(from H.V.Transformer)
Primary Interlock Switch
PK(from P.C.B)
BL(from P.C.B)
Figure 9
Latch Board
Secondary
Interlock Switch
Figure 10
WIRE COLOR
SYMBOL COLOR
WH
BK
WHITE
BLACK
BR
RD
BL
PK
GY
BROWN
RED
BLUE
PINK
GREY
N.P.
Not Provided
Interlock
Monitor Switch
Primary
Interlock Switch
7-7
D. REMOVING MAGNETRON
(Figures 11 Through 13)
(1) Remove the vent grille by loosening two screws.
(Figure 11)
(2) Remove the outcase. See page 7-6.
(3) Remove three tap tite screws securing the magnetron to the wave guide.
(4) Remove the magnetron VERY CAREFULLY.
NOTES:
•
When removing the magnetron, make sure that its dome does not hit any adjacent parts, or it may be damaged.
•
When replacing the magnetron, be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition.
•
After replacing the magnetron, check for microwave energy leakage with a survey meter Check microwave energy leakage must be below the limit of 5 mW/cm
2
. (All service adjustments should be made for minimum microwave energy leakage readings.)
Mount,All
Figure 11
Vent Grille
Door
Controller
Figure 12
(3 screws)
(1 or 2 screws)
Mounting
Plate
Out Case
Figure 13
7-8
E. REMOVING STIRRER FAN
(Figures 14 and 15)
(1) Remove one rivet ASS'Y securing it to the oven upper plate by using knife blade.
(2) Rotate slightly and pull out the stirrer fan cover.
(3) Remove the stirrer fan.
F. REMOVING DOOR (Figure 16)
(1) Remove the vent grille by two screws securing it to the outcase loosening.
(2) Lift up and draw the door.
NOTES:
•
After replacing the door, be sure to check that the primary interlock switch, the secondary interlock switch and the interlock monitor switch is in good operating normally.
•
After replacing the door, check for microwave energy leakage with a survey meter. Microwave energy leakage must be below the limit of 5mW/cm
2
. (With a
275 ml water load)
Figure 14
Figure 15
Figure 16
G. DISASSEMBLING DOOR (Figure 17)
(1) Remove the dielectric choke by using knife blade or small screw driver, etc.
(2) Remove two screws securing it to the door handle.
CAUTION: Be careful not to damage door seal plate with the screwdriver.
7-9
Figure 17
Door Screen
H. ASSEMBLING DOOR
(1) 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.
Space
(3) Carefully pull the ventilation motor ASS'Y out of the microwave oven. (See Figure 19-b)
Figure 19-b
I. REMOVING THE VENTILATION MOTOR
(1) Remove the mounting plate by loosening mounting plate screws (1 or 2 screws) securing it to the back plate.
(See Figure 18)
(2) Remove MOUNT ALL loosening one screw loosening one screw securing the ventilation Motor and back plate. (See Figure 19-a)
(1 or 2 screws)
Figure 18
Figure 19-a
7-10
K. REMOVING THE TURNTABLE MOTOR
(1) Remove the turntable.
(2) Remove the turntable shaft VERY CAREFULLY with a slotted screwdriver. (Figure 20)
(3) Remove the base plate by removing 7 screws securing it to the oven cavity. (Figure 21)
(4) Disconnect the leadwire from the turntable motor terminals.
(5) Remove the 2 screws securing the turntable motor to the oven cavity ASS'Y. (Figure 22)
NOTES:
•
Remove the leadwire from the turntable motor
VERY CAREFULLY.
•
Be sure to grasp the connector not the wires when removing.
Figure 20
Figure 21
Wire Leads
Turntable Motor
Figure 22
7-11
INTERLOCK SYSTEM
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.
ADJUSTMENT PROCEDURES
To avoid possible exposure to microwave energy leakage, adjust the door latches and interlock switches, using the following procedure.
CHECK THE DOOR LATCH AND SWITCH
CLOSING.
NOTE:
The outer cover of the microwave oven is removed.
The Interlock Monitor and Primary Interlock Switch act as the final safety switch protecting the user from microwave energy. The terminals between “COM” and
“NC” of the Interlock Monitor must close when the door is opened. After adjusting the Interlock Monitor Switch, make sure that it is correctly connected.
Mounting of the primary/monitor/secondary switches to the latch board.
(1) Set the microwave oven on its side so that you can see the latch board and the switches, as shown in
Figure 23-a.
Latch Board
(2) Close the door tightly and check gaps A and B to be sure they are no more than 1/64
”
(0.5 mm).
See Figure 23-b for close-up view of gaps A and B
(door latches). If all gaps are less than 1/64
”
(0.5 mm), adjustment of the latch board may not be necessary. Go to Steps 5 and 6 to check the sequence of the switches.
Secondary
Interlock Switch
Interlock
Monitor Switch
Primary
Interlock Switch
Figure 23-a
LATCH
NOTE:
To correct sequence of the Primary Interlock
Switch, Secondary Interlock Switch and the
Interlock Monitor Switch is very important.
If any gap is larger than 1/64
”
(0.5 mm), you will need to adjust the latch board”. Go to step 3 and follow all steps in order.
ADJUST THE LATCH AND SWITCH CLOSING
(3) Loosen the two screws holding the plastic latch board as shown.
(4) With the oven door closed tightly, move the latch board upward toward the top of the oven and/or away from the door latch until the gaps are less than 1/64
”
(0.5 mm).
Hold the latch board tightly in this position until you check the sequence of the switches in steps 5 and 6.
0-1/64"
LATCH BOARD
0-1/64"
Figure 23-b
7-12
TEST THE LATCH AND SWITCH SEQUENCE
(5) Open the oven door slowly. Watch the door latch, the Secondary Switch. Release Rod and Lever on the switches to make sure they are zero to the body of the switches in the following sequence:
- Primary Interlock Switch
- Secondary Interlock Switch
- Interlock Monitor Switch
Adjust the latch board until the switches operate in this sequence. See Steps 3 and 4.
(6) Close the oven door slowly and be sure it is tightly closed. Watch the three switches to make sure they are zero to the body of the switches in the following sequence:
- Interlock Monitor Switch
- Primary Interlock Switch
- Secondary Interlock Switch
NOTE: The Interlock Monitor Switch is an added safety check on the Primary and
Secondary Interlock Switches. If the
Primary and Secondary Interlock Switches allow the oven to operate with the door open, the Monitor Switch will blow the fuse.
(7) When you achieve the proper sequence of switches in Steps 5 and 6, tighten the latch board screws at that point.
TEST THE MICROWAVE ENERGY LEAKAGE
Make sure the microwave energy leakage is below the limit of 1mW/cm 2 (with a 275 ml water load) and
5mW/cm 2 (with a 275 ml water load without the cabinet) when measured with a survey meter.
7-13
INTERLOCK CONTINUITY TEST
A. PRIMARY INTERLOCK SWITCH TEST
When the door is opened slowly, an audible click should be heard at the same time or successively at intervals and 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.
COMPONENTS
SWITCHES
(Wire leads removed)
Check for continuity of the switch with an Ohm-meter
Primary
Switch
TEST PROCEDURE
COM
NO
B. SECONDARY INTERLOCK SWITCH TEST
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.
C. 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.
Door open
RESULTS
Door closed
Monitor
Switch
Secondary
Switch
COM
NC
COM
NO
NOTE : After checking for the continuity of switches, make sure that they are connected correctly.
WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION
EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS.
TYPE NO. SZM-V16-FA-63 OR VP-533A-OF FOR PRIMARY SWITCH
TYPE NO. SZM-V16-FA-62 OR VP-532A-OF FOR MONITOR SWITCH
TYPE NO. SZM-V16-FA-63 OR VP-533A-OF FOR SECONDARY SWITCH
7-14
TEST AND CHECKOUT PROCEDURES, AND TROUBLE SHOOTING
- CAUTIONS -
- DISCONNECT THE POWER SUPPLY CORD
FROM THE WALL OUTLET WHENEVER
REMOVINGING THE CABINET FROM THE UNIT.
PROCEED WITH THE TESTS ONLY AFTER
DISCHARGING THE HIGH VOLTAGE CAPACITOR
AND REMOVING THE WIRE LEADS FROM THE
PRIMARY WINDING OF THE HIGH VOLTAGE
TRANSFORMER. (SEE FIGURE 24)
- ALL OPERATIONAL CHECKS WITH MICROWAVE
ENERGY MUST BE DONE WITH A LOAD (1 LITER
OF WATER IN CONTAINER) IN THE OVEN.
Filament
Winding
Secondary
Winding
Primary
Winding
Figure 24
A. TEST PROCEDURES
COMPONENTS
MAGNETRON
(Wire leads are removed)
TEST PROCEDURES
1) Measure the resistance: Across the filament terminals of the magnetron with an ohm-meter on Rx1 scale.
2) Measure the resistance: Between each filament terminal of the magnetron and the chassis ground with an ohm-mater on high test scale.
RESULTS
Normal reading:
Less than 1 ohm.
Normal reading:
Infinite ohms.
NOTE: Replace the magnetron, if the magnetron checks and all of the high voltage component tests are good, but the unit still does not heat a load.
HIGH-VOLTAGE
TRANSFORMER
(Wire leads are removed)
1) Measure the resistance:
With an ohm-meter on Rx1 scale.
a. Primary winding; b. Filament winding; c. Secondary winding;
2) Measure the resistance:
With an ohm-meter on highest scale.
a. Primary winding to ground; b. Filament winding to ground;
Normal readings:
Approx. 0.2 to 0.5 ohm.
Less than 0.1 ohm.
Approx. 50 to 120 ohms.
Normal readings:
Infinite ohms.
Infinite ohms.
NOTE: A MICROWAVE ENERGY LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS
SERVICED FOR ANY REASON.
7-15
COMPONENTS TEST PROCEDURES
Measure the resistance:
(1) Terminal to terminal
Ohmmeter
HIGH-VOLTAGE
CAPACITOR
Figure 25-a
(2) Terminal to case
Ohmmeter
Figure 25-b
Measure the continuity:
(1) Forward
Ohmmeter
HIGH-VOLTAGE
DIODE
(1) Reverse
Figure 26-a
Ohmmeter
Figure 26-b
7-16
RESULTS
Normal reading:
Momentarily indicates several ohms, and then gradually returns to infinite ohms.
Abnormal reading:
Indicates continuity or infinite ohms from the beginning.
Normal readings:
Infinite.
Abnormal reading:
Indicates continuity.
Normal readings: continuity.
Abnormal reading:
Infinite.
Normal readings:
Infinite.
Abnormal reading: continuity.
COMPONENTS
TOUCH KEY
BOARD
TEST PROCEDURES
Measure the resistance between terminal pins of connector KEY CONNECTOR.
NOTE:
When reconnecting the FPC connector, make sure that the holes on the FPC connector are properly engaged with hooks on the plastic fastener.
MATRIX CIRCUIT FOR
TOUCH KEY BOARD
CONNECTOR(KEY CON)
1 2 3 4 5 6 7
N.C
N.C
N.C
POPCORN
AUTO
COOK
AUTO
REHEAT
AUTO
DEFROST
HOLD
WARM
9
STOP/
CLEAR
START
EZ ON
CUSTOM
SET
CUSTOM
COOK
TIME
COOK
POWER
LEVEL
10
VENT
H/L/OFF
LIGHT
H/L/OFF
LIGHT
TIMER
KITCHEN
TIMER
TURNTABLE
ON/OFF
HELP
CLOCK
MORE
LESS
11
1 2 3 4 5
POTATO PIZZA BEVERAGE
12
6 7 8 9 0 N.C
N.C
N.C
13
8
RESULTS
Resistance value
When When not touched touched
Less than More than
400 ohms 1 mega ohm
FPC CONNECTOR
Top
Figure 28
7
8
9
10
11
12
13
4
5
6
1
2
3
Figure 27
7-17
COMPONENTS
RELAY2
TEST PROCEDURES
Check for continuity of relay 2 with an ohm-meter.
(Remove wire leads from relay 2 and operate the unit.)
Relay 2
Figure 29
POWER
LEVEL
1
2
5
6
3
4
9
10
7
8
RESULTS
4 sec
6 sec
8 sec
10 sec
12 sec
14 sec
16 sec
18 sec
20 sec
22 sec
CAUTION: The relay connector 2 must be correctly connected Relay 2.
NOTES:
•
A MICROWAVE ENERGY 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.
B. CHECKOUT PROCEDURES
(1) CHECKOUT PROCEDURES FOR FUSE BLOWING
CAUTION: REPLACE BLOWN FUSE WITH 20 AMPERE FUSE.
PROBLEMS
Fuse blows immediately after the door is closed.
Fuse blows immediately after the door is opened.
CAUSES
Improper operation of the primary interlock, secondary interlock switches and/or the interlock monitor switch.
Fuse blows when the door is closed and START key is touched.
Malfunction of the high voltage transformer; the high voltage capacitor including the diode, the magnetron, the blower motor or the circuit board.
NOTES:
•
If the fuse is blown by an improper switch operation, replace the all Interlock switches, PCB Ass’y and the fuse at the same time. After replacing the the all Interlock switches, PCB Ass’y,Fuse with new ones, make sure that they are correctly connected.
•
Check for microwave energy leakage according to INTERLOCK ADJUSTMENT PROCEDURES on page 7-
12 when the primary interlock, secondary interlock switches and/or the interlock monitor switches are adjusted or replaced.
7-18
18 sec
16 sec
14 sec
12 sec
10 sec
8 sec
6 sec
4 sec
2 sec
0
(2) CHECKOUT PROCEDURES FOR RELAY.
- PROBLEM (A) -
FAN motor and oven lamp turn on without touching
START key when the door is closed.
NO YES
GOOD
Remove the mate connector of I/O
CON from the circuit board.
Does the unit still operate?
NO YES
Replace the circuit board
Defective
RELAY1
Replace
RELAY1
- PROBLEM (B) -
FAN motor and oven lamp turn on When the door is closed and START key is touched.
YES
NO
GOOD
Measure the voltage at pin NO.
35 of U01
Voltage reading: 0 Vdc
10 of U03
Voltage reading: about 15V
NO YES
Replace the circuit board
Defective
RELAY1 or poor connection of
RELAY1
Replace
RELAY1 or correct the connection.
7-19
(3) CHECKOUT PROCEDURES FOR CIRCUIT
BOARD
The following symptoms indicate a defective circuit board.
1) The start function fails to operate but the high voltage Systems, the interlock switches, the door sensing and the relay check good.
2) The unit with a normal relay continuously operates.
3) Proper temperature measurement is not obtained.
4) The buzzer does not sound or continues to sound.
5) Some segments of one or more digits do not light up, or they continue to light up, or segments light when they should not.
6) Wrong figures appear.
7) The figures of all digits.
8) Some of the indicators do no flicker light up.
9) The clock does not keep time properly.
NOTE: A MICROWAVE ENERGY LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS
SERVICED FOR ANY REASON.
7-20
7-21
7-22
7-23
7-24
7-25
#EV#
MODEL : EXV 1711W
EXV 1711B
EXV 1711BS
EXPLODED VIEW
DOOR PARTS
13581A
14760A
13213A
13536A
WTP004
13552A
13720D
14890A
WTT028
14970A
14026A
13650A
8-1
#EV#
26638A
CONTROLLER PARTS
24781M
23572A
WTP018
268711
* 07
24810P
8-2
#EV#
33530A
OVEN CAVITY PARTS
WTT029
WTT021
34960A
33550P
WTT028
WTT029
35026G
34810Q
33112U
WTT022
368771
63303A
34930R
330342
WTT022
33550L
35230A
8-3
36912C
330341
63302A
WTT022
#EV#
LATCH BOARD PARTS
43500A
43501A
466001
WSZ084
44510A
8-4
466003
466001
#EV#
INTERIOR PARTS (I)
35889A
33052A
55892A
55893A
54930F
53550F
34370T
33390G
56324A
WSZ002
WTT021
54810C
55238A
50CZZH
56851D
WTT021
36549S
WTP013
56877
2
WTP002
WSZ002
56930G
WSZ002
53300B
WSZ002
56170D
340511
8-5
#EV#
*01
*02
*04
56912B
INTERIOR PARTS (II)
53550L
36549V
WTT034
56549F
56804A
56901A
55262A
WTT029
55231C
56930V
WTT028
55900A
56820A
56411A
50FZZA
WTP018
568771
WTT028
8-6
#EV#
INSTALLATION PARTS
63861A
63300M
65862D
65862B
8-7
SCHEMATIC DIAGRAM OF P.C.B
8-14
PRINTED CIRCUIT BOARD
8-15
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