Sharp R-220FW, R-214FW User Manual

SERVICE MANUAL

S3208R220FPW/

MICROWAVE OVEN

R-214FW
R-220FW

MODELS

R-214FW
R-220FW

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 con-

R-220FW

TABLE OF CONTENTS

PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO

AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY...................INSIDE FRONT COVER

BEFORE SERVICING ......................................................................................................INSIDE FRONT COVER

WARNING TO SERVICE PERSONNEL................................................................................................................1

MICROWAVE MEASUREMENT PROCEDURE ...................................................................................................2

FOREWORD AND WARNING...............................................................................................................................3

PRODUCT SPECIFICATIONS ..............................................................................................................................4

GENERAL INFORMATION...................................................................................................................................4

OPERATION..........................................................................................................................................................6

TROUBLESHOOTING GUIDE ..............................................................................................................................9

TEST PROCEDURE............................................................................................................................................10

TOUCH CONTROL PANEL.................................................................................................................................18

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE................................................................22

PICTORIAL DIAGRAM ........................................................................................................................................28

CONTROL PANEL CIRCUIT ............................................................................................................................... 29

PRINTED WIRING BOARD ................................................................................................................................. 29

PARTS LIST ........................................................................................................................................................30

PACKING AND ACCESSORIES .........................................................................................................................34

tain circuitry capable of producing very high voltage and
current, contact 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..)

Page

SHARP CORPORATION

This document has been published to be used for after
sales service only.
The contents are subject to change without notice.

35

R-214FW
R-220FW

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/cm2. The owner of the unit should be instructed not to use
the unit until the oven has been brought into compliance.

WARNING TO SERVICE PERSONNEL

Microwave ovens contain circuitry capable of pro­ducing very high voltage and current, contact with
following parts
fatal, electrical shock.

(Example)
High Voltage Capacitor, High Voltage Power Trans-

former, Magnetron, High Voltage Rectifier Assem­bly, High Voltage Harness etc..

Read the Service Manual carefully and follow all
instructions.

may result in a severe, possibly

Don't Touch !
Danger High Voltage

R-214FW
R-220FW

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 SHOCK.

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 high­voltage capacitor (that is the connecting lead of the high­voltage rectifier) 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.

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.

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)
minutes. 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 re­examine the connections to the component being tested.

When all service work is completed and the oven is fully
assembled, the microwave power output should be checked
and microwave leakage test should be carried out.

1

R-214FW
R-220FW

MICROWAVE MEASUREMENT PROCEDURE

A. Requirements:

1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven
should not 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 useful 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 sensing switch shall prevent microwave radiation emission
in excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission
in excess of 5 mW/cm2 at any point 5cm or more from the external surface of the oven.

B. Preparation for testing:
Before beginning the actual measurement of leakage, proceed as follows:

1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.
Important:

Survey instruments that comply with the requirement for instrumentation 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±15 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 such as glass or plastic.
The placing of this standard load in the oven is important not only 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 the water begins to boil before the survey is completed,

replace it with 275 ml of cool water.

C. 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 meter.

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/cm2,
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.

2

SERVICE MANUAL

R-214FW
R-220FW

MICROWAVE OVEN

R-214FW/ R-220FW

FOREWORD

This Manual has been prepared to provide Sharp Electronics Corp.
Service Personnel with Operation and Service Information for the
SHARP MICROWAVE OVEN, R-214FW and R-220FW.

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 microwave
radiation hazard.

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 carried out only by trained service
personnel.

DANGER

Certain initial parts are intentionally not grounded and present
a risk of electrical shock only during servicing. Service
personnel - 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.

PRODUCT DESCRIPTION

GENERAL INFORMATION

OPERATION

TROUBLESHOOTING GUIDE AND
TEST PROCEDURE

TOUCH CONTROL PANEL

COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE

WIRING DIAGRAM

PARTS LIST

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 microwave

exposure, by themselves, or when they are damaged, loosened
or removed.

SHARP ELECTRONICS CORPORATION

SHARP PLAZA, MAHWAH,

NEW JERSEY 07430-2135

3

R-214FW
R-220FW

PRODUCT DESCRIPTION

SPECIFICATIONS

ITEM DESCRIPTION

Power Requirements 120 Volts

60 Hertz

Single phase, 3 wire grounded
Power Consumption 1200W / Approx. 10.3 Amperes
Power Output 800 W nominal of RF microwave energy (IEC Test procedure)

Operating frequency 2450 MHz
Case Dimensions Width 18-1/8"

Height10-7/8"

Depth 13-7/8"
Cooking Cavity Dimensions Width 12-5/8"

(0.7 Cubic feet) Height 7-7/8"

Depth 13-1/4"
Control Complement Touch Control System

Clock (1:00 - 12:59)

Timer (0 - 99 minutes 99 seconds)

Microwave Power for Variable Cooking

Repetition Rate;

P-HI ................................... Full power throughout the cooking time

P-90 .................................................... approx. 90% of FULL Power

P-80 .................................................... approx. 80% of FULL Power

P-70 .................................................... approx. 70% of FULL Power

P-60 .................................................... approx. 60% of FULL Power

P-50 .................................................... approx. 50% of FULL Power

P-40 .................................................... approx. 40% of FULL Power

P-30 .................................................... approx. 30% of FULL Power

P-20 .................................................... approx. 20% of FULL Power

P-10 .................................................... approx. 10% of FULL Power

P-0 ...................................... No power throughout the cooking time

POPCORN pad, MINUTE PLUS pad

REHEAT pad, COOK pad, DEFROST pad

Number selection pads

TIMER / CLOCK pad

POWER LEVEL pad

START pad

STOP/CLEAR pad
Oven Cavity Light Yes
Safety Standard UL Listed.

FCC Authorized

DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J

GENERAL INFORMATION

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 accordance with the National Electrical Code and local codes and ordinances.
In the event of an electrical short circuit, grounding reduces the risk of electric shock by providing an escape wire for the
electric current.

WARNING: Improper use of the grounding plug can result in a risk of electric shock.

4

R-214FW
R-220FW

Electrical Requirements
The electrical requirements are a 115 -120 volt 60 Hz, AC only, 15 or 20 amp. fused electrical supply. It is recommended
that a separate circuit serving only this appliance be provided. When installing this appliance, observe all applicable codes
and ordinances.
A short power-supply cord is provided to reduce risks of becoming entangled

Grounded
Receptacle Box

in or tripping over a longer cord.
Where a two-pronged wall-receptacle is encountered, it is the personal
responsibility and obligation of the customer to contact a qualified electrician
and have it replaced with a properly grounded three-pronged wall receptacle
or have a grounding adapter properly grounded and polarized. If the extension
cord must be used, it should be a 3-wire, 15 amp. or higher rated cord. Do not
drape over a countertop or table where it can be pulled on by children or tripped

3-Pronged
Plug

Grounding Pin

3-Pronged Receptacle

over accidentally.
CAUTION: DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE THE ROUND GROUNDING PRONG FROM

THIS PLUG.

OVEN DIAGRAM

1 Door open button

Push to open door.
2 Oven door with see-through window
3 Safety door latches

The oven will not operate unless the door is

securely closed.
4 Door hinges
5 Door seals and sealing surfaces
6 Turntable motor shaft
7 Removable turntable support

Carefully place the turntable support in the center

of the oven floor.
8 Removable turntable

Place the turntable securely on the turntable

support. The turntable will rotate clockwise or

counterclockwise. Only remove for cleaning.
9 Ventilation openings (Rear)
10 Oven light

It will light when oven is operating.
11 Waveguide cover: DO NOT REMOVE.
12 Auto-Touch control panel
13 Time display: 99 minutes, 99 seconds

5

4

32

9

6

10

11

TOUCH CONTROL PANEL

13

8

12

7

1

NOTE:
Some one-touch cooking features such as
"MINUTE PLUS" are disabled after three min­utes when the oven is not in use. These fea­tures are automatically enabled when the door
is opened and closed or the STOP/ CLEAR pad
is pressed.

POPCORN

REHEAT

COOK

DEFROST

5

MINUTE

PLUS

1.Casserole

4.Beverage

2.Soup

5.Dinner Plate

3.Pizza

6.Fresh Rolls/Muffins

1.Baked Potatoes

3.Frozen Vegetables

2.Fresh Vegetables

4.Frozen Entrees

1.Ground Meat

3.Boneless Poultry

2.Steaks/Chops

4.Bone-in Poultry

R-214FW R-220FW

R-214FW
R-220FW

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

The following is a description of component functions during
oven operation.

OFF CONDITION

Closing the door activates door sensing switch and second­ary interlock switch. (In this condition, the monitor switch
contacts are opened.)
When oven is plugged in, 120 volts A.C. is supplied to the
control unit. (Figure O-1).

1. The display will show flashing "88:88".

2. To set any program or set the clock, touch the STOP/
CLEAR pad. The display will clear, and " : " will appear.

COOKING CONDITION

Program desired cooking time by touching the NUMBER
pads. And program the power level by touching the POWER
LEVEL pad.
When the START pad is touched, 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)

RELAY CONNECTED COMPONENTS
RY-1 oven lamp/turntable motor/fan motor
RY-2 power transformer

2. 120 volts A.C. is supplied to the primary winding of the
power transformer and is converted to about 3.35 volts
A.C. output on the filament winding, and approximately
2000 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 feed­box, 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
and primary interlock relay are activated with the following
results. The circuits to the oven lamp, turntable motor,
the cooling fan motor, and the high voltage components
are de-energized, and the digital read-out displays the
time still remaining in the cook cycle when the door was
opened.

7. The monitor switch is electrically monitoring the operation
of the secondary interlock switch and primary interlock
relay (RY2) and is mechanically associated with the door

so that it will function in the following sequence.

(1) When the door opens from the closed position, the

secondary interlock switch, door sensing switch and
primary interlock relay (RY2) open their contacts. Then
the monitor switch contacts close.

(2) 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
(RY2) fail with the contacts closed when the door is opened,
the closing of the monitor switch contacts will form a short
circuit through the C/T fuse, primary interlock relay (RY2)
and secondary interlock switch, causing the C/T fuse to
blow.

POWER LEVEL COOKING

When Variable Cooking Power is programmed, the 120
volts A.C. is supplied to the power transformer intermittently
through the contacts of relay (RY-2) which is operated by
the control unit within a 32 second time base. Microwave
power operation is as follows:

VARI-MODE ON TIME OFF TIME
P-HI (100% power) 32 sec. 0 sec.
P-90 (approx. 90% power) 30 sec. 2 sec.
P-80 (approx. 80% power) 26 sec. 6 sec.
P-70 (approx. 70% power) 24 sec. 8 sec.
P-60 (approx. 60% power) 22 sec. 10 sec.
P-50 (approx. 50% power) 18 sec. 14 sec.
P-40 (approx. 40% power) 16 sec. 16 sec.
P-30 (approx. 30% power) 12 sec. 20 sec.
P-20 (approx. 20% power) 8 sec. 24 sec.
P-10 (approx. 10% power) 6 sec. 26 sec.
P-0 (0% power) 0 sec. 32 sec.

Note: The ON/OFF time ratio does not correspond with

the percentage of microwave power, because
approx. 3 seconds are needed for heating of the
magnetron filament.

POWER OUTPUT REDUCTION

If the oven is set for more than 20 minutes at 80, 90 or 100%
power level, after the first 20 minutes the power level will
automatically adjust itself to 70% power to avoid overcook­ing.

6

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. CLOCK APPEARS ON DISPLAY

R-214FW
R-220FW

NOTE: " " indicates components with potentials above 250V.

C/T FUSE

A3

120V AC
60 Hz

GRN

OL FM

Figure O-1. Oven Schematic-Off Condition

SCHEMATIC

NOTE: CONDITION OF OVEN

1. DOOR CLOSED

2. COOKING TIME PROGRAMMED

3. VARIABLE COOKING CONTROL "P-HI"

4. "START" PAD TOUCHED

CONTROL UNIT

OVEN
LAMP

SECONDARY
INTERLOCK
SWITCH

TEMPERATURE
FUSE (OVEN)

(RY-1)

TTM

TURN­TABLE
MOTOR

A1

N.O.

(RY-2)

B2 B1

FAN
MOTOR

PRIMARY
INTERLOCK
RELAY

DOOR
SENSING
SWITCH

COM.

MONITOR
SWITCH

POWER
TRANSFORMER

CAPACITOR

0.82µF
AC2100V

RECTIFIER

MAGNETRON

120V AC
60 Hz

C/T FUSE

A3

CONTROL UNIT

GRN

OL FM

OVEN
LAMP

SECONDARY
INTERLOCK
SWITCH

TEMPERATURE
FUSE (OVEN)

(RY-1)

TTM

TURN­TABLE
MOTOR

A1

N.O.

(RY-2)

B2 B1

FAN
MOTOR

PRIMARY
INTERLOCK
RELAY

DOOR
SENSING
SWITCH

COM.

Figure O-2. Oven Schematic-Cooking Condition

7

MONITOR
SWITCH

POWER
TRANSFORMER

CAPACITOR

0.82µF
AC2100V

RECTIFIER

MAGNETRON

R-214FW
R-220FW

DESCRIPTION AND FUNCTION OF COMPONENTS

DOOR OPEN MECHANISM

The door is opened by pushing the open button on the
control panel, refer to the Figure D-1.
When the open button is pushed, the open button pushes up
the switch lever, and then the switch lever pushes up the
latch head. The latch heads are moved upward and re­leased from latch hook. Now the door will open.

Latch Heads

Latch Hook

Door
Sensing
Switch

Door

Switch Lever

Monitor
Switch

Secondary
Interlock
Switch

Figure D-1. Door Open Mechanism

DOOR SENSING AND SECONDARY INTERLOCK
SWITCHES

The secondary interlock switch is mounted in the lower
position of the latch hook and the door sensing switch in the
primary interlock system is mounted in the upper position of
the latch hook. They are activated by the latch heads on the
door. When the door is opened, the switches interrupt the
power to all high voltage components. A cook cycle cannot
take place until the door is firmly closed thereby activating
both interlock switches. The primary interlock system con­sists of the door sensing switch and primary interlock relay
located on the control circuit board.

MONITOR SWITCH

The monitor switch is activated (the contacts opened) by the
latch head on the door while the door is closed. The switch
is intended to render the oven inoperative, by means of
blowing the C/T fuse, when the contacts of the primary
interlock relay (RY2) 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 normally
closed. At this time the primary interlock relay (RY2) and
secondary interlock switch are in the OFF condition
(contacts open) due to its being normally open contact
switches.

2. As the door goes to a closed position, the monitor switch
contacts are first opened and then the door sensing
switch and secondary interlock switch contacts close.

3. If the door is opened, and the primary interlock relay
(RY2) and the secondary interlock switch contact fail to

open, the C/T fuse blows simultaneously with closing of
the monitor switch contacts.

CAUTION: BEFORE REPLACING A BLOWN C/T FUSE,

TEST THE DOOR SENSING SWITCH, PRI­MARY INTERLOCK RELAY (RY2), SECOND­ARY INTERLOCK SWITCH AND MONITOR
SWITCH FOR PROPER OPERATION. (RE­FER TO CHAPTER "TEST PROCEDURE").

NOTE:C/T FUSE AND MONITOR SWITCH ARE

REPLACED AS AN ASSEMBLY.

TURNTABLE MOTOR

The turntable motor rotates the turntable located on the
bottom of the oven cavity, so that the food on the turntable
is cooked evenly. The turntable may turn in either direction.

COOLING FAN MOTOR

The cooling fan motor drives a blade which draws external
cool air. This cool air is directed through the air vents
surrounding the magnetron and cools the magnetron. This
air is channelled through the oven cavity to remove steam
and vapours given off from the heating foods. It is then
exhausted through the exhausting air vents at the oven
cavity.

TEMPERATURE FUSE (OVEN)

The temperature fuse, located on the top of the oven cavity,
is designed to prevent damage to the oven by fire. If the food
load is overcooked, by either error in cook time or defect in
the control unit, the temperature fuse will open.
Under normal operation, the temperature fuse remains
closed. However, when abnormally high temperatures are
reached within the oven cavity, the temperature fuse will
open at 248˚F(120˚C), causing the oven to shut down.

C/T FUSE

1. The C/T fuse blows when the contacts (COM-NO) of the
primary interlock relay (RY2) and secondary interlock
switch remain closed with the oven door open and when
the monitor switch closes.

2. If the wire harness or electrical components are short­circuited, this C/T fuse blows to prevent an electric shock
or fire hazard.

3. The C/T fuse, located near the magnetron, is designed
to prevent damage to the magnetron. If an over heated
condition develops in the magnetron due to cooling fan
failure, obstructed air guide, dirty or blocked air intake,
etc., the C/T fuse will open.

Under normal operation, the C/T fuse remains closed.
However, when abnormally high temperatures are reached
within the oven cavity, the C/T fuse will open at 248˚F
(120˚C), causing the oven to shut down or when the electric
currents beyond 15A flow, the C/T fuse will open.

8

R-214FW
R-220FW

TROUBLESHOOTING GUIDE

Never touch any part in the circuit with your hand or an uninsulated tool while the power supply is connected.

When troubleshooting the microwave oven, it is helpful to follow the Sequence of Operation in performing the checks. Many
of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure letter which
will be found in the "Test Procedure "section.

IMPORTANT: If the oven becomes inoperative because of a blown C/T fuse, check the monitor switch, primary

interlock relay (RY2), door sensing switch and secondary interlock switch before replacing the C/T fuse.
If C/T fuse is replaced, the monitor switch must also be replaced. Use part FFS-BA030WRKZ as an
assembly.

IMPORTANT: Whenever troubleshooting is performed with the power supply cord disconnected. It may in, some cases,

be necessary to connect the power supply cord 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.

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.

9