Sharp R21lcf Service Manual

							
PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE EXPO-
SURE TO EXCESSIVE MICROWAVE ENERGY
BEFORE SERVICING
CHAPTER 1. WARNING TO SERVICE PERSONNEL
CHAPTER 2. MICROWAVE MEASUREMENT PRO-
CEDURE
CHAPTER 3. FOREWORD AND WARNING
CHAPTER 4. PRODUCT DESCRIPTION
CHAPTER 5. GENERAL INFORMATION
CHAPTER 6. OPERATIONCHAPTER 7. TROUBLESHOOTING GUIDE 
CHAPTER 8. TEST PROCEDURES
CHAPTER 9. TOUCH CONTROL PANEL ASSEMBLY
CHAPTER 10. PRECAUTIONS FOR USING LEAD-
FREE SOLDER
CHAPTER 11. COMPONENT REPLACEMENT AND 
ADJUSTMENT PROCEDURE
CHAPTER 12. CIRCUIT DIAGRAMS
Parts List
S7607R21LCFP/
LIGHT DUTY COMMERCIAL
MICROWAVE OVEN
R-21LCF
SERVICE MANUAL
R21LCF
MODEL
CONTENTS
SHARP CORPORATIONThis document has been published to be used
for after sales service only.
The contents are subject to change without notice.
In the interest of user-safety the oven should be restored to its original
condition and only parts identical to  those specified should be used.
WARNING TO SERVICE PERSONNEL: Microwave ovens contain
circuitry capable of producing very high voltage and current, con-
tact with following parts may result in a severe, possibly fatal,
electrical shock. (High Voltage Capacitor, High Voltage Power
Transformer, Magnetron, High Voltage Rectifier Assembly,  High
Voltage Harness etc..)
1000W/R- 21LC
COMMERCIALMICROWAVEOVEN
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T 
						

							
CONTENTS
PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE EXPO-
SURE TO EXCESSIVE MICROWAVE ENERGY
CHAPTER 1. WARNING TO SERVICE PERSONNEL
[1] Before Servicing .........................................1-1
[2]  When the testing is co mpleted, ..................1-1
[3] After repairing .............................................1-1
CHAPTER 2. MICROWAVE MEASUREMENT PRO-
CEDURE
[1] Requirements: .............. ..............................2-1
[2] Preparation for testing: ...............................2-1
[3] Leakage test: ..............................................2-1
CHAPTER 3. FOREWORD AND WARNING
[1] FOREWORD ..............................................3-1
[2] WARNING ..................................................3-1
[3] DANGER ....................................................3-1
CHAPTER 4. PRODUCT DESCRIPTION
[1] SPECIFICATIONS .............................. ........4-1
CHAPTER 5. GENERAL INFORMATION
[1] GROUNDING INSTRUCTIONS .................5-1
[2] OVEN DIAGRAM........................................5-1
CHAPTER 6. OPERATION
[1]  DESCRIPTION OF OPERATING SE- QUENCE ...................................................6-1
[2] OVEN SCHENATIC ....................................6-1
[3]  DESCRIPTION AND FUNCTION OF  COMPONENTS ..........................................6-2
CHAPTER 7. TROUBLESHOOTING GUIDE 
[1] TROUBLESHOOTING CHART .................7-1
CHAPTER 8. TEST PROCEDURES
[1]  Procedure A: MAGNETRON ASSEMBLY  TEST ..........................................................8-1
[2] Procedure B:  POWER TRANSFORMER 
TEST ..........................................................8-1
[3]  Procedure C: HIGH VOLTAGE RECTIFI- ER TEST ....................................................8-1
[4]  Procedure D: HIGH VOLTAGE CAPACI- TOR TEST ..................................................8-2
[5]  Procedure E: THERMAL CUT OUT TEST .....8-2
[6]  Procedure F: SECONDARY INTERLOCK  SWITCH TEST ...........................................8-2
[7]  Procedure F: PRIMARY INTERLOCK  SYSTEM TEST...... .....................................8-3
[8]  Procedure G: MONITOR SWITCH TEST .....8-3
[9]  Procedure H: BLOWN MINITOR FUSE  TEST ..........................................................8-3
[10]  Procedure I: NOISE FILTER TEST.............8-4
[11] Procedure J:  CONTROL PANEL ASSEM-
BLY TEST ...................................................8-4 [12]  Procedure L: RELAY TEST....................
..... 8-5
[13]  Procedure M: FOIL PATTERN ON THE  PRINTED WIRING BOARD TEST ......... ..... 8-5
CHAPTER 9. TOUCH CONTROL PANEL ASSEM-
BLY
[1]  OUTLINE OF TOUCH CONTROL PANEL  ..... 9-1
[2]  SERVICING FOR TOUCH CONTROL  PANEL ................................................... ..... 9-1
CHAPTER 10. PRECAUTIONS FOR USING LEAD-
FREE SOLDER
[1] Employing lead-free solder .................... ... 10-1
[2]  Using lead-free wire solder .................... ... 10-1
[3] Soldering................................................ ... 10-1
CHAPTER 11. COMPONENT REPLACEMENT AND 
ADJUSTMENT PROCEDURE
[1] WARNING.............................................. .... 11-1
[2]  OUTER CASE REMO VAL ......................... 11-1
[3] POWER TRANSFORMER REMOVAL .. .... 11-1
[4]  HIGH VOLTAGE RECTIFIER ASSEMBLY  AND HIGH VOLTAGE CAPACITOR RE-
MOVAL .................................................. .... 11-2
[5] MAGNETRON REMOVAL ..................... .... 11-2
[6]  CONTROL PANEL ASSEMBLY REMOV- AL .......................................................... .... 11-2
[7]  OVEN LAMP AND LAMP SOCKET RE- MOVAL .................................................. .... 11-2
[8]  POSITIVE LOCK  CONNECTOR (NO- CASE TYPE) REMOVA L ........................... 11-3
[9] ANTENNA MOTOR REMOVAL ............. .... 11-3
[10]  COOLING FAN MOTOR REMOVAL...... .... 11-3
[11]  POWER SUPPLY CORD REPLACE-
MENT..................................................... .... 11-4
[12]  DOOR SENSING SWITCH/SECONDARY  INTERLOCK SWITCH AND MONITOR 
SWITCH REMOVAL .............................. .... 11-4
[13]  DOOR SENSING SWITCH/SECONDARY  INTERLOCK SWITCH AND MONITOR 
SWITCH ADJUSTMENT ....................... .... 11-5
[14]  DOOR PARTS REMOVAL ..................... .... 11-5
[15]  ANTENNA MOTOR SHAFT REPLACE- MENT..................................................... .... 11-6
[16]  INSTALLATION OF CERAMIC SHELF.. .... 11-7
CHAPTER 12. CIRCUIT DIAGRAMS
[1] Pictorial Diagram  (Figure S-1) .................. 12-1
[2]  Control Panel Circuit (Figure S-2).......... ... 12-2
[3]  Printed Wiring Board (Figure S-3) ......... ... 12-3
Parts List 
						

							
R21LCF
i
R21LCFService Manual PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID
POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY
BEFOR SERVICING
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.
BEFORE SERVICING
Before servicing an operative unit, perform a microwave emission check as per the Microwave
Measurement Procedure outlined in this service manual.
If microwave emissions level is in excess of the specified limit, contact SHARP ELECTRONICS
CORPORATION immediately @1-800-237-4277.
If the unit operates with the door open, service person should 1) tell the user not to operate the oven
and 2) contact SHARP ELECTRONICS CORPORATION and Food and Drug Administration's
Center for Devices and Radiological Health immediately.
Service personnel should inform SHARP ELECTRONICS CORPORATION of any certified unit found
with emissions in excess of 4mW/cm . The owner of the unit should be instructed not to use the unit
until the oven has been brought into compliance.
2 
						

							
R21LCF
1 – 1
R21LCFService Manual CHAPTER 1. WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of producing very high voltage and cu rrent, contact with following parts may result in a severe, possibly
fatal, electrical shock.
(Example)
High Voltage Capacitor, High Voltage Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc..
Read the Service Manual carefully and follow all instructions.
[1] Before Servicing
1. Disconnect the power supply cord  , and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
WARNING: RISK OF ELECTRIC SHO CK. DISCHARGE THE HIGH-
VOLTAGE CAPACITOR BEFORE SERVICING.
The high-voltage capacitor remains charged about 60 seconds after
the oven has been switched off. Wait for 60 seconds and then short-
circuit the connection of the high-vo ltage capacitor (that is the connect-
ing lead of the high-voltage rectifie r) against the chassis with the use
of an insulated screwdriver. 
Whenever troubleshooting is performed the power supply  must be
disconnected. It may, in some cases, be necessary to connect the
power supply after the outer case has been removed, in this event,
1) Disconnect the power supply cord, and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Disconnect the leads to the primary of the power transformer.
5) Ensure that the leads remain isolated from other components and oven chassis by using insulation tape.
6) After that procedure, reconnect the power supply cord.
[2] When the testing is completed,
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Reconnect the leads to the primary of the power transformer.
5. Reinstall the outer case (cabinet).
6. Reconnect the power supply cord after the outer case is installed.
7. Run the oven and check all functions.
[3] After repairing
1. Reconnect all leads removed  from components during testing.
2. Reinstall the outer case (cabinet).
3. Reconnect the power supply cord after the outer case is installed.
4. Run the oven and check all functions.
Microwave ovens should not be run empty. To test for the presence of
microwave energy within a cavity, place a cup of cold water on the
oven turntable, close the door and set  the power to HIGH and set the
microwave timer for two (2) mi nutes. When the two minutes has
elapsed (timer at zero) carefully check that the water is now hot. If the
water remains cold carry out  Before Servicing procedure and re-
examine the connections to the component being tested. 
When all service work is completed  and the oven is fully assembled,
the microwave power output shoul d be checked and microwave leak-
age test should be  carried out.
Don't Touch !
Danger High Voltage 
						

							
R21LCF
2 – 1
R21LCFService Manual CHAPTER 2. MICROWAVE MEASUREMENT PROCEDURE
[1] Requirements:
1. Microwave leakage limit (Power density limit): The power density of microwave ra diation emitted by a microwave oven should no t exceed 1mW/
cm2 at any point 5cm or more from the external surface of the  oven, measured prior to acquisition by a purchaser, and thereafter ( through the use-
ful life of the oven), 5 mW/cm2 at any point 5cm or more from the external surface of the oven. 
2. Safety interlock switches: Primary interlock relay and door se nsing switch shall prevent microwave radiation emission in exce ss of the requirement
as above mentioned, secondary interlock switch shall prevent  microwave radiation emission in excess of 5 mW/cm
2 at any point 5cm or more from
the external surface of the oven. 
[2] Preparation for testing:
Before beginning the actual measurem ent of leakage, proceed as follows:
1. Make sure that the actual instrument is operat ing normally as specified in its instruction booklet.
Important:
Survey instruments that comply with the requirement for inst rumentation as prescribed by the performance standard for microwave  ovens, 21 CFR
1030.10(c)(3)(i), must be used for testing.
2. Place the oven tray in the oven cavity.
3. Place the load of 275 ±5 ml (9.8 oz) of tap water initially at 20 ±5 °C (68 °F) in the center of the oven cavity.
The water container shall be a low form of 600 ml (20 oz) beaker  with an inside diameter of approx. 8.5 cm (3-1/2 in.) and made of an electrically
nonconductive material su ch as glass or plastic.
The placing of this standard load in the oven is important not onl y to protect the oven, but also to insure that any leakage is measured accurately.
4. Set the cooking control on Full Power Cooking Mode 
5. Close the door and select a cook cycle of several minutes. If t he water begins to boil before the survey is completed, replace it with 275 ml of cool
water.
[3] Leakage test:
Closed-door leakage test (microwave measurement)
1. Grasp the probe of the survey instrument and hold it perpendicular to the gap between the door and the body of the oven.
2. Move the probe slowly, not faster than 1 in./sec. (2.5 cm/sec .) along the gap, watching for the maximum indication on the met er.
3. Check for leakage at the door screen, sheet metal seams and other  accessible positions where the continuity of the metal has been breached (eg.,
around the switches, indicator, and vents).
While testing for leakage around the door pull the door away from  the front of the oven as far as is permitted by the closed latch assembly.
4. Measure carefully at the point of highest leakage and make  sure that the highest leakage is no greater than 4mW/cm
2, and that the secondary
interlock switch and the primary interlock relay do turn the oven OFF before any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report. 
						

							
R21LCF
3 – 1
R21LCFService Manual CHAPTER 3. FOREWORD AND WARNING
[1] FOREWORD
This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with  Operation and Service Information for the SHARP
MICROWAVE OVEN, R-21LCF.
It is recommended that service personnel carefully study the entire  text of this manual so that they will be qualified to render satisfactory customer
service.
Check the interlock switches and the door seal carefully. Special  attention should be given to avoid electrical shock and micro wave radiation hazard.
[2] WARNING
Never operate the oven until the following points are ensured.
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is not any other visible damage with the oven.
Servicing and repair work must be carr ied out only by trained service personnel.
[3] DANGER
Certain initial parts are intentionally not grounded and present a risk of electrical shock only during servicing. Service pers onnel - Do not
contact the following parts while the appliance is energized; 
High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly,  High Voltage Harness; 
If provided, Vent Hood, Fan assembly, Cooling Fan Motor.
All the parts marked “ “ on parts list are used at voltages more than 250V.
Removal of the outer wrap gives access to voltage above 250V.
All the parts marked “*“ on parts list may cause undue microwav e exposure, by themselves, or when they are damaged, loosened or  removed. 
						

							
R21LCF
4 – 1
R21LCFService Manual CHAPTER 4. PRODUCT DESCRIPTION
[1] SPECIFICATIONS
ITEM DESCRIPTION
Power Requirements120 Volts 
14 Amperes
60 Hertz
Single phase, 3 wire grounded
Power Output 1000 watts (IEC Test procedure)
Operating frequency 2450 MHz 
Outer case Dimensions Width  20-1/2 (520mm)
Height 12-1/8 (309mm)
Depth  16       (406mm)
Cooking Cavity Dimensions Width 13-7/8  (353mm)      
NOTE: Internal capacity is calculated by measuring
Height  8-1/ 8 (207mm)                  maximum width, depth and height.
Depth 14-5/8  (370mm)                  Actual capacity for holding food is less.
Control Complement Light Up Dial (6 minutes)
No cooking control
Oven Cavity Light Yes
Safety Standard UL Listed.
FCC Authorized
DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J, NSF certified 
						

							
R21LCF
5 – 1
R21LCFService Manual CHAPTER 5. GENERAL INFORMATION
[1] GROUNDING INSTRUCTIONS
This oven is equipped with a three prong grounding plug. It must be plugged into a wall receptacle that is properly installed and grounded in accor-
dance with the National Electrical  Code and local codes and ordinances.
In the event of an electrical short circui t, grounding reduces the risk of electric shoc k by providing an escape wire for the electric current.
WARNING: Improper use of the grounding plug can result in a risk of electric shock.
Electrical Requirements
The electrical requirements are a 120 volt 60 Hz,  AC only, 15 amp. or more protected electrical
supply. It is recommended that a separate circui t serving only this appliance be provided. When
installing this appliance, obser ve all applicable codes and ordinanc es. A short power-supply cord is
provided to reduce risks of becoming entangled in  or tripping over a longer cord. Where a two-
pronged wall-receptacle is encountered, it is the per sonal responsibility and obligation of the cus-
tomer to contact a qualified electrician and ha ve it replaced with a properly grounded three-
pronged wall receptacle or have a grounding ada pter properly grounded and polarized. If the
extension cord must be used, it should be a 3-wi re, 15 amp. or higher rated cord. Do not drape
over a countertop or table where it can be pul led on by children or tripped over accidentally.
CAUTION: DO NOT UNDER ANY CIRCUM STANCES CUT OR REMOVE THE ROUND
GROUNDING PRONG FROM THIS PLUG. 
[2] OVEN DIAGRAM
1. OVEN
1. Back splash cover
2.  Side splash cover
3. Oven light
4. Ceramic shelf
5. Control panel
6. Cavity face plate
7. Door latch openings
8. Door latches
9. Door hinges
10.Door seals and sealing surfaces
11. Door handle
12.Oven door with see-through window
13.Air ventilation cover and openings 14.Power supply cord
15.Air intake openings
16.Outer case cabinet
2. TOUCH CONTROL PANEL
3-Pronged
Plug
Grounded
Receptacle Box
Grounding Pin
3-Pronged Receptacle
1
1413
912
11
765
15
16
10
32
4
8
TIME GUIDE FOR ONE SERVING
15 - 30 sec.
Bagel, Roll
Muffin, Pastry
Pie Slice 30 - 60 sec.
Hot Dog
Pizza Slice
Small Sandwich
1-2min.
Beverage, Soup
Large Sandwich
Popcorn, 1.5 oz. 2-3min.
Casserole, Stew
Chili, Chowder
Popcorn, 3.5 oz.
With the door closed,turn the timer to
the desired time. Oven will begin
operating immediately.
To shut oven off manually,return timer
to "0".
INSTRUCTIONS
0
10
20
30
40
50
11.5
2
2.5
3
4
5
6
A B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
TLight Up Dial for
setting cooking time. 
						

							
R21LCF
6 – 1
R21LCFService Manual CHAPTER 6. OPERATION
[1] DESCRIPTION OF OPERATING SEQUENCE 
The following is a description of com ponent functions during oven operation.
1. OFF CONDITION
Closing the door activates door sensing switch and secondary inter-
lock switch. (In this condition, the monitor switch contacts are opened.)
When oven is plugged in, 120 volts A.C.  is supplied to the noise filter
and the control unit (Figure O-1).
2. COOKING CONDITION
When the Light Up Dial is tur ned, the following operations occur:
1) The contacts of the relays are closed and components connected to the relays are turned on as follows.
(For details, refer to Figure O-2)
2) 120 volts A.C. is supplied to the primary winding of the power trans- former and is converted to about 3.2 volts A.C. output on the fila-
ment winding, and approximately 2150 volts A.C. on the high
voltage winding.
3) The filament winding voltage heats the magnetron filament and the H.V. winding voltage is sent to a voltage doubler circuit.
4) The microwave energy produced by the magnetron is channelled through the waveguide into the cavity feed-box, and then into the
cavity where the food is placed to be cooked. 5) Upon completion of the cooking 
time, the power transformer, oven
lamp, etc. are turned off, and the generation of microwave energy
is stopped. The oven will revert to the OFF condition.
6) When the door is opened during a cook cycle, monitor switch, door sensing switch, secondary interlock switch, relay (RY2) and pri-
mary interlock relay (RY1) are acti vated with the following results.
The circuits to the antenna motor, the cooling fan motor, and the
high voltage components are de-energized, the oven lamp remains
on, and the digital read-out displays  the time still remaining in the
cook cycle when the door was opened.
7) The monitor switch electrically  monitors the operation of the sec-
ondary interlock switch and control relay (RY1) and is mechanically
associated with the door so that it will function in the following
sequence.
a) When the door opens from the closed position, the primary interlock relay (RY1) and secondary interlock switch open their
contacts. Then the monitor  switch contacts close.
b) When the door is closed from the open position, the monitor switch contacts open first. Then the contacts of the secondary
interlock switch and door sensing switch close.
If the secondary interlock switch and  primary interlock relay (RY1) fail
with the contacts closed when the door is opened, the closing of the
monitor switch contacts will form  a short circuit through the monitor
fuse, secondary interlock switch, and primary interlock relay(RY1),
causing the monitor fuse to blow.
[2] OVEN SCHENATIC
1. Off Condition
                                                         Figure O-1. Oven Schematic-Off Condition
RELAY CONNECTED COMPONENTS
RY-1  oven lamp/antenna motor/fan motor
RY-2 power transformer
SCHEMATIC
NOTE: CONDITION OF OVEN
1. LIGHT UP DIAL OFF.
2. DOOR CLOSED.
FUSE
LINE CROSS CAPACITOR 0.22μF AC250V
NOISE SUPPRESSION COIL
LINE BYPASSCAPACITOR
0.0033μF / AC 250V
LINE BYPASS
CAPACITOR
0.0033μF / AC 250V 20A
NOISE FILTER
NL
AC120V
60 Hz
OL FM AM
OVEN
LAMP
FAN
MOTORANTENNA
MOTOR POWER
TRANSFORMER
CAPACITOR
1.00 μF
2300V
DOOR SENSING
SWITCH
SECONDARY
INTERLOCK SWITCH
CONTROL UNIT
THERMAL
CUT-OUT
125ºC (OVEN) THERMAL
CUT-OUT
145ºC (MAG.)
PRIMARY
INTERLOCK
RELAY
COOK
RELAY
MONITOR SWITCH
MAGNETRON
RECTIFIER RY1
RY2
A5
A3 A1 
						

							
R21LCF
6 – 2
2. Cooking Condition
                                                        
Figure O-2. Oven Schematic-Cooking Condition
[3] DESCRIPTION AND FUNCTION OF COMPONENTS
1. DOOR OPEN MECHANISM
The door is opened by grasping the door handle, refer to Figure D-1.
When the door handle is grasped,  the handle lever is pulled. And then
the upper and lower latch heads are moved upward by the handle
lever, and they are released from the latch hook. Now the door will
open.
                     Figure D-1. Door Open Mechanism.
2. DOOR SENSING A ND SECONDARY INTERLOCK
SWITCHES
The secondary interlock switch is mounted in the upper position of the
latch hook and the door sensing switch in the primary interlock system
is mounted in the lower position of the latch hook. The secondary inter-
lock switch is activated by the la tch switch lever A. The latch switch
lever A is activated by the upper latch head. The door sensing switch
is activated by the latch switch lever  C. The latch switch lever C is acti-
vated by the lower latch head. When the door is opened, the switches
interrupt the power to all high voltage components. A cook cycle can-
not take place until the door is fi rmly closed thereby activating both
interlock switches. The primary inte rlock system consists of the door
sensing switch and primary interlock relay located on the control circuit
board.
3. MONITOR SWITCH
The monitor switch is activated  (the contacts opened) by the latch
switch lever B on the latch hook while the door is closed. The latch
switch lever B is activated by the lower latch head. The switch is
intended to render the oven inoperative, by means of blowing the mon-
itor fuse, when the contacts of the primary interlock relay (RY1) and
secondary interlock switch fail to open when the door is opened.
Functions:
1) When the door is opened, the monitor switch contacts close (to the ON condition) due to their being nor mally closed. At this time the
primary interlock relay (RY1) and secondary interlock switch are in
the OFF condition (contacts open) due to their being normally open
contact switches.
2) As the door goes to a closed posit ion, the monitor switch contacts
are first opened and then the door sensing switch and the second-
ary interlock switch contacts close. (On opening the door, each of
these switches operate inversely.)
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. LIGHT UP DIAL ON.
FUSE
LINE CROSS CAPACITOR 0.22μF AC250V
NOISE SUPPRESSION COIL
LINE BYPASSCAPACITOR
0.0033μF / AC 250V
LINE BYPASS
CAPACITOR
0.0033μF / AC 250V 20A
NOISE FILTER
NL
AC120V
60 Hz
OL FM AM
OVEN
LAMP
FAN
MOTORANTENNA
MOTOR POWER
TRANSFORMER
CAPACITOR
1.00 μF
2300V
DOOR SENSING
SWITCH
SECONDARY
INTERLOCK SWITCH
CONTROL UNIT
THERMAL
CUT-OUT
125ºC (OVEN) THERMAL
CUT-OUT
145ºC (MAG.)
PRIMARY
INTERLOCK
RELAY
COOK
RELAY
MONITOR SWITCH
MAGNETRON
RECTIFIER RY1
RY2
A5
A3 A1
Latch Hook
Latch Switch
Lever A
Latch Switch
Lever B
Latch Switch
Lever C
Latch Head
Latch Head Handle
Lever
Door
Handle
Latch
LeverSecondary
Interlock
Switch
Monitor
Switch
Door
Sensing
Switch