MODEL 721.60282000 721.60289000
DIVISION 20
BASIC FIELD MANUAL
FOR
MICROWAVE OVEN
MODEL 721.60282000 721.60289000
March, 2000
MODEL 721.60282000 721.60289000
CAUTION
WARNING TO SERVICE TECHNICIANS
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 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 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.
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MODEL 721.60282000 721.60289000
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.
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MODEL 721.60282000 |
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721.60289000 |
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MECHANICAL SERVICE INFORMATION |
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TABLE OF CONTENTS |
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1. |
Adjustment Procedures ....................................................................................................................................... |
3 |
2. |
Precautions on Installation .................................................................................................................................. |
5 |
3. |
General Precautions in Use................................................................................................................................. |
5 |
4. |
Trial Operation..................................................................................................................................................... |
5 |
5. |
Specifications ...................................................................................................................................................... |
6 |
6. |
Overall Circuit Diagram ....................................................................................................................................... |
7-8 |
7. |
Operating Procedures ......................................................................................................................................... |
9-11 |
8. |
Procedure for Measuring Microwave Energy Leakage........................................................................................ |
12-13 |
9. |
Disassembly Instructions..................................................................................................................................... |
14-18 |
10. |
Interlock Continuity Test .................................................................................................................................... |
19 |
11. |
Test and Checkout Procedures, and Troubleshooting |
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A. Test Procedures............................................................................................................................................. |
20-22 |
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B. Checkout Procedures..................................................................................................................................... |
23-25 |
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C. Troubleshooting ............................................................................................................................................. |
26-30 |
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1. ADJUSTMENT PROCEDURES
To avoid possible exposure to microwave energy leakage, adjust the door latches and interlock switches, using the following procedure.
ONLY AUTHORIZED SERVICE PERSONNEL SHOULD MAKE THIS ADJUSTMENT.
The Interlock Monitor and Primary Interlock Switch acts 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. See Figures 1-a and 1-b throughout this procedure.
CHECK THE DOOR LATCH AND SWITCH
CLOSING.
NOTE: The outer cover of the microwave oven is removed.
(1)Set the microwave oven on its side so that you can see the latch board and the switches, as shown in
Figure 1-a.
(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 1-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.
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-U, L. Go to step 3 and follow all steps in order.
MODEL 721.60282000 721.60289000
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.
TEST THE LATCH AND SWITCH SEQUENCE
(5)Open the oven door slowly. Watch the door latch, the Primary 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
(8)Using a survey meter, make sure the microwave energy is below 5 mW/cm.sq.
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MODEL 721.60282000 721.60289000
LATCH BOARD
DOOR LATCH |
SECONDARY |
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INTERLOCK |
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SWITCH |
A
MONITOR
INTERLOCK
SWITCH
B
PRIMARY
INTERLOCK
SWITCH
Figure 1-a
LATCH
0-1/64"
LATCH BOARD
0-1/64" |
Figure 1-b |
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2. PRECAUTIONS ON INSTALLATION
(Figure 2)
A.Plug the power supply cord into a 120 V AC, 60 Hz, single-phase power source with a capacity of at least 20 amperes.
B.Since the unit weights about 38 lbs, be sure to place it on a sturdy and flat surface.
C.Avoid placing the unit in a location where there is direct heat or splashing water.
D.Place the unit as far away as possible from TV, radio, etc. to prevent interference.
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.
Properly Polarized and
Grounded
Outlet
Three-Pronged(Grounding)
Plug
Figure 2
3. 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 turntable tray 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.
MODEL 721.60282000 721.60289000
4. 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.Touch the STOP/CLEAR and the COOK TIME keys.
C.Set cooking time for 10 minutes by touching “1” and then “0” three times. “1000” appears in the display window.
D.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.
E.After about 5 minutes, make sure the primary interlock switch, the secondary interlock switch and the interlock monitor and oven lamp switch operate properly by opening and closing the door several times. Touch the START key each time the door is closed.
F.Continue operating the unit. Four long beep sound signal is heard when the time is up. The unit will shut off automatically.
G.Confirm the water is hot.
H.Finally, measure the output power according to “POWER OUTPUT MEASUREMENT” on page 13.
5. FEATURES AND SPECIFICATIONS
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 thermostat
(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.
C.Cooking time can be displayed on the digital readout.
D.Three different cooking stages can be set. The oven remembers three cooking stages and changes from one cooking stage to another. This is made possible with the memory function of the microprocessor.
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MODEL 721.60282000 721.60289000
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SPECIFICATIONS |
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Rated Power Consumption .......................................... |
1530W maximum |
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Output .......................................................................... |
1100W maximum (*IEC 705 Rating standard) |
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Adjustable 100W through 1100W, 11 steps |
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Frequency .................................................................... |
2,450 MHz ± 50 MHz |
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Power Supply ............................................................... |
120V ±12V AC, 60Hz |
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Rated Current............................................................... |
13.3 Amp. |
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Magnetron Cooling....................................................... |
Forced Air Cooling |
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Microwave Stirring........................................................ |
Turntable |
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Rectification.................................................................. |
Rectification Voltage Doubler Half-Wave |
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Door Sealing ................................................................ |
Choke System |
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Safety Devices ............................................................. |
Thermostat: |
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Open at 90°C ± 5°C |
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Open at 75°C ± 5°C |
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Fuse(20A) |
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Primary Interlock Switch |
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Secondary Interlock Switch |
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Interlock Monitor |
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Magnetron .................................................................... |
2M246 |
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High Voltage Capacitor ................................................ |
Capacitor: 1.00µF, 2.1KV Ac |
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High Voltage Diode ...................................................... |
350mA, 9.0KV |
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Cavity Lamp ................................................................. |
125V, 20W |
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Timer ............................................................................ |
Digital, up to 99 mm. 99 sec. (in each cooking stage) |
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Tray .............................................................................. |
Tempered Safety Glass |
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Overall Dimensions ...................................................... |
207/8”(W) x 123/8”(H) x 151/2”(D) |
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Oven Cavity Size.......................................................... |
133/4”(W) x 93/8”(H) x 143/8”(D) |
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Effective Capacity of Oven Cavity................................ |
1.1 Cu.ft. |
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Accessories.................................................................. |
Use and Care Manual ,Turntable, |
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Rotating Ring Assembly. |
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SWITCH CHART |
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PRIMARY |
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SECONDARY |
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INTERLOCK |
SWITCH MODE |
INTERLOCK |
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INTERLOCK |
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MONITOR |
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SWITCH |
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SWITCH |
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SWITCH |
CONDITIONS |
COM |
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COM |
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COM |
NO |
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NO |
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NC |
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DOOR OPEN |
∞ |
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∞ |
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0 |
DOOR CLOSED |
0 |
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0 |
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∞ |
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NOTE: Use the above switch chart with circuit diagram on page 7.
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MODEL 721.60282000 721.60289000
6. OVERALL CIRCUIT DIAGRAM A. SCHEMATIC DIAGRAM
MGT/OVEN |
N |
L AC 120V/60Hz |
THERMOSTAT |
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SINGLE PHASE ONLY |
WH
BK
L.V. TRANSFORMER
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BK |
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2 |
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WH |
OL |
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BL |
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3 |
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OVEN |
RD |
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4 |
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LAMP |
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WH |
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RELAY 1 |
5 |
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FM |
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6 |
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GN |
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GN |
FAN |
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7 |
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MOTOR |
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WH |
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8 |
PK |
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BK |
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(CN1) |
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SECONDARY |
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RELAY 2 |
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INTERLOCK |
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SWITCH |
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TTM |
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TURNTABLE |
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3 |
2 1 |
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MOTOR |
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CN4 |
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WH |
RD |
BK |
YL |
MONITOR SWITCH |
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(C) |
(NC) |
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BN |
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RC |
RS |
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H.V.TRANSFORMER |
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WH |
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RD |
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HUMIDITY |
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MAGNETRON |
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SENSOR |
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H.V. CAPACITOR |
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NOTE: |
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1. DOOR IS OPEN. |
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2.RS: SENSING |
H.V.DIODE |
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ELEMENT |
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RC: COMPENSATING |
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ELEMENT |
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3. WIRE COLOR. |
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SYMBOL COLOR |
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CONTROL MODULE |
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WH |
WHITE |
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BK |
BL |
WH |
GN |
PK |
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BK |
BLACK |
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1 |
2 3 |
4 5 |
6 7 |
8 |
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BL |
BLUE |
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YL |
YELLOW |
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(8 PIN) |
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PK |
PINK |
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CONNECTOR |
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RD |
RED |
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GN |
GREEN |
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BN |
BROWN |
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FUSE 20A
BK
PRIMARY INTERLOCK SWITCH (NO)
SAFETY NOTE: THE SHADED AREAS ON THIS SCHEMATIC DIAGRAM INCORPORATE SPECIAL FEATURES |
IMPORTANT FOR PROTECTION FROM MICROWAVE RADIATION, FIRE, ELECTRICAL SHOCK, AND HAZARDS. WHEN SERVICING IT IS ESSENTIAL THAT ONLY MANUFACTURER’S SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SHADED AREAS OF THE SCHEMATIC DIAGRAM. |
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NOTICE: SINCE THIS IS BASIC SCHEMATIC DIAGRAM, THE VALUES OF COMPONENTS AND SOME PARTIAL CONNECTIONS ARE SUBJECT TO CHANGE FOR IMPROVEMENT. |
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IMPORTANT |
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MODEL 721.60282000 721.60289000
B. MATRIX CIRCUIT FOR TOUCH KEY BOARD
Figure 4
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7. OPERATING PROCEDURES A. OVEN CONTROL PANEL
Quick Touch
Sensor
Auto Defrost
Used in setting
Auto Defrost.
Cook Time
Used to set cooking time.
Option
Kitchen Timer
You can use your microwave oven as a timer.
Stop/Clear
Stops the oven and clears all entries except CLOCK.
Once cooking has begun, however, CLEAR will function only after STOP has been touched.
MODEL 721.60282000 721.60289000
Display Window- Shows:
*Time of day.
*Cooking time.
*Cooking power level. It also function as a countdown timer when cooking.
Clock
Used in setting
Time of Day.
Express Defrost
Numbers-
Used to enter the:
*Time of day.
*Cooking time.
*Cooking power.
*Food weight for defrost.
Power
Used select cooking power level.
Add Minute
Used to set cooking time quickly and directly.
Start
Starts the oven.
NOTE: A "beep" sounds when you touch a "key" on the control panel, to indicate that you have entered a setting.
Figure 5
-9-
B. PANEL INSTRUCTIONS
The entire operation is done by simple touch control pads.
(1) DISPLAY WINDOW.
The Display includes a clock and indicators that tell you time of day, cooking time settings, and cooking functions selected.
(2) QUICK TOUCH SENSOR Key
The oven's sensor will tell the oven how long to cook depending on quantity of the food in the oven.
(3) AUTO DEFROST Key
Touch this pad to thaw meat, fish, or poultry by entering
aweight.
(4)NUMBER PADS
Touch Number Pads to enter cooking time, power level, quantities, or weights.
(5) COOK TIME Key
Touch this pad to set a cooking time.
(6) OPTION Key
Touch this pad to change the oven's default settings for sound, clock, scroll speed, Lbs/Kg and demo on/off choice.
MODEL 721.60282000 721.60289000
(7) STOP/CLEAR Key
Touch this pad to stop the oven or clear entries.
(8) CLOCK Key
Touch this pad to enter the time of day.
(9) EXPRESS DEFROST Key
Touch this pad to defrost foods quickly.
(10) POWER Key
Touch this pad to set a cooking power.
(11) ADD MINUTE Key
Touch this pad to cook at 100% cook power for 1 to 99 minutes.
(12) KITCHEN TIMER Key
Touch this pad to use your microwave oven as a kitchen timer.
(13) START Key
Touch this pad to start all entries (except the functions which start automatically) and to turn Child Lock on or off.
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MODEL 721.60282000 721.60289000
C. EASY USE CHART |
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(1) CLOCK |
(7) SENSOR POPCORN |
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1. Touch STOP/CLEAR. |
1. Touch STOP/CLEAR. |
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2. Touch CLOCK. |
2. Touch POPCORN. |
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Touch numbers for correct time of day. |
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Touch START. |
(8) SENSOR REHEAT |
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1. Touch STOP/CLEAR. |
(2) KITCHEN TIMER |
2. Touch REHEAT. |
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Touch STOP/CLEAR. |
3. Touch number from 1 to 3 |
2. Touch KITCHEN TIMER. |
(Touch 1: DINNER PLATE, Touch 2: SOUP/SAUCE, |
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Touch correct numbers for time. |
Touch 3: CASSEROLE) |
4. |
Touch START. |
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(9) AUTO DEFROST |
(3) CHILD LOCK |
1. Touch STOP/CLEAR. |
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To set: |
2. Touch AUTO DEFROST. |
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Touch STOP/CLEAR. |
Three different defrosting levels are provided. |
2. |
Touch “START” more than 2 seconds. |
(MEAT, POULTRY, FISH) |
To cancel: |
3. Enter the weight of your food in decimal |
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Touch STOP/CLEAR. |
increments from 0.1 to 6.0 pounds. |
2. |
Touch “START” more than 2 seconds. |
4. Touch START |
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5. At beeping, turn food over by following the |
(4) ADD MINUTE |
instructions in the manual. |
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Touch STOP/CLEAR. |
6. After turning food over, touch START to resume |
2. |
Touch ADD MINUTE. |
defrosting. |
(5) TIMED COOKING |
(10) EXPRESS DEFROST |
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1. Touch STOP/CLEAR. |
1. Touch STOP/CLEAR. |
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2. Touch COOK TIME. |
2. Touch EXPRESS DEFROST. |
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Touch numbers for cooking time. |
3. Touch number from 1 to 3 |
4. Touch POWER. |
(Touch 1: MEAT, Touch 2: POULTRY, Touch 3: FISH) |
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5. |
Touch number for cooking power level. |
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6. |
Touch START. |
(11) OPTION |
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1. Touch STOP/CLEAR. |
(6) MULTI-STAGE COOKING |
2. Touch OPTION. |
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1. |
Touch STOP/CLEAR. |
3. Touch number from 1 to 5 |
2. Touch COOK TIME. |
Touch 1: SOUND ON/OFF |
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Touch numbers for cooking time. |
Touch 2: CLOCK ON/OFF |
4. Touch POWER. |
Touch 3: SCROLL SPEED |
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5. |
Touch number for cooking power level. |
Touch 4: LBS/KG |
6. |
Repeat steps 2-5 to set 2nd cooking stage. |
Touch 5: DEMO ON/OFF |
7. |
Touch START. |
4. Touch correct number for setting. |
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MODEL 721.60282000 721.60289000
8.PROCEDURE FOR MEASURING MICROWAVE ENERGY LEAKAGE
A. CAUTIONS
(1)Be sure to check a microwave emission prior to servicing the oven if the oven is operative prior to servicing.
(2)The service personnel should inform the manufacturer, importer, or assembler of any certified oven unit found to have a microwave emission level in excess of 5mW/cm.sq. 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.
(3)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 Health 1390 Piccard Drive
Rockville, Maryland 20850
(4)The service personnel should check all surface and vent openings for microwave emission testing.
(5)Check for microwave energy leakage after every servicing. The power density of the microwave radiation leakage emitted by the microwave oven should not exceed 1mW/cm.sq. And always start measuring of an unknown field to assure safety for operating personnel from radiation leakage.
NOTE: The standard is 5mW/cm.sq. while in the customer’s home. 1mW/cm.sq. stated here is manufacturer’s own voluntary standard for units in customer’s home.
EQUIPMENT
•Electromagnetic energy leakage monitor (NARDA 8100B, HOLADAY HI 1501)
•600cc glass beaker
•Glass thermometer 100°C
Figure 6
B. MEASURING MICROWAVE ENERGY LEAKAGE
(1)Pour 275±15cc of 20±5°C water in a beaker which is graduated to 600 cc, and place the beaker in the center of the oven.
(2)Set the energy leakage monitor to 2,450 MHz and use it following the manufacturer’s recommended test procedure to assure correct result.
(3)When measuring the leakage, always use the 2 inch (5cm) spacer supplied with the probe.
(4)Operate the oven at its maximum output.
(5)Measure the microwave radiation using and electromagnetic radiation monitor by holding the probe perpendicular to the surface being measured. (See Figure 7)
Move probe along shaded area.
Probe scanning speed less than 2.5 cm/sec.
Figure 7
C. 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.
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D.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 5mW/cm.sq. Leakage for a fully assembled oven (Before the latch switch (primary) is interrupted) with the door in a slightly opened position - less than
1mW/cm .sq.
E.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.
F.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 1mW/cm.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.
(3)At least once a year, have the electromagnetic energy leakage monitor checked for calibration by its manufacturer.
MODEL 721.60282000 721.60289000
G. POWER OUTPUT MEASUREMENT
(1)Fill the test beaker with 59 ˚F(15 ˚C) ~ 75 ˚F(24 ˚C) 1 liter tap water.
(2)Stir the water in the beaker with thermometer ( ˚F or ˚C) and measure temperature as T1.
(3)Place the beaker on the center of turntable.
(4)Set for one (1) minute and three (3) seconds and operate the oven at high power.
NOTE: The additional three (3) seconds is to allow the magnetron to begin generating power.
(5)When the heating is finished, stir the water again with thermometer and measure the temperature of water as T2.
(6)Subtract T1 from T2, this will give you the temperature rise.
(7)The microwave power output is within specification, if the temperature rise is as shown below:
|
Temperature Rise |
|
Line Voltage |
Degrees ˚F |
Degrees ˚C |
|
|
|
120 V |
18.9 ~ 25.2 |
10.5 ~ 14 |
108 V |
Min. 17.5 |
Min 9.7 |
(8)Power output will be influenced by line voltage of power supply. Consequently, correct power output must be measured within 120V AC ± 1 Volt while unit is operating.
SPECIAL TIP
• This oven used the button head screws.
Button Head (Torx style 2)
•When you remove the screws, using the tamper-resistant Torx driver have a pin-in-head.
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9. DISASSEMBLY INSTRUCTIONS
IMPORTANT NOTES:
UNIT MUST BE DISCONNECTED FROM ELECTRICAL OUTLET WHEN MAKING REPAIRS, RE-PLACEMENTS, ADJUSTMENTS AND CONTINUITY 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 10KOHM RESISTOR IN SERIES TO GROUND. WHEN RECONNECTING THE WIRE LEADS TO ANY PART, MAKE SURE THE WIRING CONNECTIONS AND LEAD COLORS ARE CORRECTLY MATCHED ACCORDING TO THE OVERALL CIRCUIT DIAGRAM. (ESPECIALLY SWITCHES AND HIGH VOLTAGE CIRCUIT.)
A. REMOVING OUT CASE (Figures 8)
(1)Remove three screws from the rear section.
(2)Remove one screw from the side section.
(3)Push the outer case back about 1 inch (3cm).
(4)Lift the case from the set.
Figure 8
B.REMOVING POWER AND CONTROL CIRCUIT BOARD(Figure 9)
(1)Open the door.
(2)Remove two screws, securing the circuit board.
(3)Disconnect the lead wire from RELAY(RY2) on the circuit board.
(4)Lift up and pull out control panel assembly carefully from the cavity.
(5)Disconnect the lead wire from connector(CN1) on the circuit board.
CAUTION: DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE SERVICING.
MODEL 721.60282000 721.60289000
(6)Pull down and remove the circuit board from the control panel.
(7)Remove the F.P.C connector from the terminal socket.
Remove screw |
securing screw |
ground screw |
Lift up and pull out control panel |
F.P.C.Connector |
Circuit Board |
Control Panel |
Figures 9 |
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C. DOOR GROSS ASSEMBLY REMOVAL
(1) Open the door.
(2) Remove the choke cover cap very carefully with a flat-blade screwdriver.
CAUTION : Be careful not to damage door seal plate with the screwdriver.
(3) Lift up and pull out 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/cm.sq. (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.
MODEL 721.60282000 |
721.60289000 |
Remove choke cover cap |
Remove choke cover cap |
Door seal plate |
Figure 10 |
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