Sears 721.66339 User manual

삼흥
정판
DIVISION 20
BASIC FIELD MANUAL
FOR
MICROWAVE OVEN
MODEL 721.66339800
February, 2008
MODEL 721.66339

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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TABLE OF CONTENTS
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
------------------------------------------------------------------------------------------------------------------------------------ 9-10
8. Procedure for Measuring Microwave Energy Leakage
--------------------------------------------------------------------------------------- 11-12
9. Disassembly Instructions ------------------------------------------------------------------------------------------------------------------------------ 13-17
10. Interlock Continuity Test
---------------------------------------------------------------------------------------------------------------------------------- 18
11. Test and Checkout Procedures, and Troubleshooting
A. Test Procedures
------------------------------------------------------------------------------------------------------------------------------------ 19-21
B. Checkout Procedures ----------------------------------------------------------------------------------------------------------------------------- 22-24
C. Troubleshooting ------------------------------------------------------------------------------------------------------------------------------------- 25-29
12. Exploded view ------------------------------------------------------------------------------------------------------------------------------------------- 30-37
13. Part Reference list -------------------------------------------------------------------------------------------------------------------------------------- 38-39
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.
MODEL 721.66339
MECHANICAL SERVICE INFORMATION
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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.
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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LATCH
LATCH BOARD
0-1/64"
0-1/64"
LATCH BOARD
MONITOR
INTERLOCK
SWITCH
PRIMARY
INTERLOCK
SWITCH
A
SECONDARY
INTERLOCK
SWITCH
Figure 1-a
Figure 1-b
DOOR LATCH
DOOR LATCH