Amana Rcs511a Service Manual

Microwave Oven
Service Manual

RCS10MPA

CAUTION

BEFORE SERVICING THE UNIT, READ THE
SAFETY PRECAUTIONS IN THIS MANUAL.

RS511P
RS511MB

RCS511A
RFS511G
URS511MB
URS511P
URCS511A
RFS511SW2A

RCS10MPSA
RFS12MPSA

RFS12G

This device is to be serviced only by properly qualified service personnel.
Consult the service manual for proper service procedures to assure continued safety operation and for precautions to be
taken to avoid possible exposure to excessive microwave energy.

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.

SAFETY PRECAUTIONS

(Page)

SAFETY PRECAUTIONS

---------------------------------------------------------------------

Inside front cover

SPECIFICATIONS

-----------------------------------------------------------------------------------------------------

1-1

CAUTIONS

--------------------------------------------------------------------------------------------------------------

2-1

INSTALLATIONS

------------------------------------------------------------------------------------------------------

3-1

OPERATING INSTRUCTIONS

------------------------------------------------------------------------------------

4-1

COOKING DISPLAYS

---------------------------------------------------------------------------------------------------------

4-6

PROGRAMMING DISPLAYS

------------------------------------------------------------------------------------------------

4-6

OPERATION

-----------------------------------------------------------------------------------------------------------------------

4-7

PROGRAMMING

----------------------------------------------------------------------------------------------------------------

4-8

SCHEMATIC DIAGRAM

----------------------------------------------------------------------------------------------------

4-10

CIRCUIT DESCRIPTION

---------------------------------------------------------------------------------------------------

4-11

SERVICE INFORMATION

------------------------------------------------------------------------------------------

5-1

TOOLS AND MEASURING INSTRUMENTS

---------------------------------------------------------------------------

5-1

MICROWAVE LEAKAGE TEST

--------------------------------------------------------------------------------------------

5-1

MEASUREMENT OF MICROWAVE POWER OUTPUT

-----------------------------------------------------------

5-3

DISASSEMBLY AND ADJUSTMENT

-------------------------------------------------------------------------------------

5-3

INTERLOCK CONTINUITY TEST

------------------------------------------------------------------------------------------

5-7

COMPONENT TEST PROCEDURE

--------------------------------------------------------------------------------------

5-8

TROUBLE SHOOTING

------------------------------------------------------------------------------------------------------

5-11

EXPLODED VIEW

-----------------------------------------------------------------------------------------------------

6-1

SCHEMATIC DIAGRAM OF P.C.B.

------------------------------------------------------------------------------

7-1

PRINTED CIRCUIT BOARD

-------------------------------------------------------------------------------------------------

7-2

CONTENTS

1-11-11-11-1

SPECIFICATIONS

Power Requirement

Magnetron

, 0

Power Requirement

Magnetron

, 0

This microwave oven is designed for commercial use only.

It is not recommended for built-in Installation.

ITEM

MODEL

Power Requirement

Power Output

Microwave Frequency

Magnetron

Timer

Outside Dimensions

Cavity Dimensions

Net Weight

Shipping weight

Control Complement

DESCRIPTION

RS511P /

RS511MB

RCS511A / RFS511G

URS511MB

/

URS511P

URCS511A

/

RFS511SW2A

230 Volts AC 50 Hz 240 Volts AC 50 Hz
1,60 Watts

Single phase, 3 wire grounded

1,100 Watts full microwave power (IEC 60705)

2,450 MHz

2M282
0 ~ 60 min.

51 lbs (approx.)

58 lbs (approx.)

Touch Control System

Clock : 00 ~ 60

Microwave Power for Variable Cooking

Power level
HIGH -------------------------------Full power throughout the cooking time
70% (Med.-High)----------------approx. 70% of Full power
50% (Med.-Low) ---------------approx. 50% of Full power
20% (Low) -----------------------approx. 20% of Full power

Power Requirement

Magnetron

,,,, , 0,1,70 Watts ,,,,,

SPECIFICATIONS

SPECIFICA

Back side

21

3

/4

”(W) x 14

1

/4

”(H) x 17

7

/8

”(D)

14

1

/4

”(W) x 8

7

/8

” (H) x 16

3

/8

”(D)

Nameplate Location

¥ DO NOT operate on a 2-wire extension cord during

repair and use.

¥ NEVER TOUCH any oven components or wiring during

operation.

¥ BEFORE TOUCHING any parts of the oven, always

remove the power plug from the outlet.

¥ For about 30 seconds after the oven stops, an electric

charge remains in the high voltage capacitor. When
replacing or checking, you must discharge the high
voltage capacitor by shorting across the two terminals
with an insulated screwdriver.

¥

Remove your watches whenever working close to or

replacing the Magnetron.

¥ DO NOT touch any parts of the control panel circuit. A

resulting static electric discharge may damage this

P.C.B.
¥ NEVER operate the oven with no load.
¥ NEVER injure the door seal and front plate of the oven

cavity.
¥ NEVER put iron tools on the magnetron.
¥ NEVER put anything into the latch hole and the

interlock switches area.

¥ Proper operation of the microwave oven requires that

the magnetron be assembled to the waveguide and
cavity. Never operate the magnetron unless it is
properly installed.

¥ Be sure that the magnetron gasket is properly

installed around the dome of the tube whenever
installing the magnetron.

2-1

CAUTIONS

Unlike other appliances, the microwave oven is
high-voltage and high-current equipment.
Though it is free from danger in ordinary use,
extreme care should be taken during repair.

THE OVEN IS TO BE SERVICED ONLY
BY PROPERLY QUALIFIED SERVICE
PERSONNEL.

MICROWAVE RADIATION

Personnel should not be exposed to the
microwave energy which may radiate from the
magnetron or other microwave generating
device if it is improperly used or connection.
All input and output microwave connections,
waveguide, flange, and gasket must be secure
never operate the device without a microwave
energy absorbing load attached.
Never look into an open waveguide or antenna
while the device is energized.

Gasket

ANTENNA

COOLING FIN

MAGNETRON
CHASSIS GROUND

FILAMENT
TERMINALS

MAGNETRON

INSTALLATIONS

3-1

BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.

INSTALLING

1. Empty the microwave oven and clean inside it with

a soft, damp cloth. Check for damage such as
misaligned door, damage around the door or dents
inside the cavity or on the exterior.

2. Put the oven on a counter, table, or shelf that is

strong enough to hold the oven and the food and
utensils you put in it. (The control panel side of the
oven is the heavy side. Use care when handling.)

3. Do not block the vent and the air intake openings.

Blocking vent or air intake openings can cause
damage to the oven and poor cooking results.
Make sure the microwave oven legs are in place to
ensure proper air flow.

4. The oven should not be installed in any area where

heat and steam are generated, because they may
damage the electronic or mechanical parts of the
unit.
Do not install the oven next to a conventional
surface unit or above a conventional wall oven.

5. Use microwave oven in an ambient temperature

less than 104°F(40°C).

EARTHING INSTRUCTIONS

This microwave oven is designed to be used in a fully
earthed condition.
It is imperative, therefore, to make sure it is properly
earthed before servicing

WARNING­THIS APPLIANCE
MUST BE EARTHED

IMPORTANT

The wires in this mains lead are colored in
accordance with the following code:

Green-and-yellow: Earth
Blue: Neutral
Brown: Live

As the colors of the wires in the mains lead of this
appliance may not correspond with the colored
markings identifying the terminals in your plug,
proceed as follows.

6. Place the microwave oven on a sturdy and flat

surface at least 10 cm(4 inches) from the wall.

7. Place the microwave oven as far away as possible

from TV, RADIO, COMPUTER, etc., to prevent
interference.

8. Do not touch the front glass during or after cooking

of the Grill and Combination mode.
This glass is very hot during heater operating.

9. Do not operate the oven at microwave and

combination mode with Grill rack placed in the
cavity when the oven is empty.

10cm

The wire which is colored green-and-yellow must be
connected to the terminal in the plug which is marked
with the letter E or by the earth symbol ( ) or
colored green or green-and-yellow.

The wire which is colored blue must be connected to
the terminal in the plug which is marked with the letter
N or colored black.

The wire which is colored brown must be connected
to the terminal in the plug which is marked with the
letter L or colored red.

4-1

FEATURES

Window Door Screen

Electronic Control

Safety Door Lock System

CONTROL PANEL

Display

Some items in display can be seen but will not glow.

Pads

TIME ENTRY

Pads 1-0

HOLD 0%,
DEFROST 20%,
MEDUIM 50%,
MED-HI 70%

STOP/RESET

START

Use to enter heating time without changing
preprogrammed number pads.

Use to begin heating with preprogrammed
times and power levels or to enter times for
“Manual Time Entry” cooking.

Use to select power level. Oven can heat at
full or reduced power. If oven power level is
set to 0% oven does not heat for
programmed time. If no power level is
selected, oven operates at 100% power.

Use to exit programming mode and stop
cooking during cooking cycle.

Use to start “Manual Time Entry” program
or restart interrupted cooking cycle. Use to
advance to next user option. Use to save
times and power levels when programming
pads.

RS511P / URS511P

4-2

FEATURES

Window Door Screen

Electronic Control

Safety Door Lock System

CONTROL PANEL

Display

Some items in display can be seen but will not glow.

Pads

TIME ENTRY

Pads 1-0

POWER
LEVEL

STOP/RESET

START

QTY2x

Use to enter heating time without changing
preprogrammed number pads.

Use to begin heating with preprogrammed
times and power levels or to enter times for
“Manual Time Entry” cooking.

Use to select power level. Oven can heat at
full or reduced power. If oven power level is
set to 0% oven does not heat for
programmed time. If no power level is
selected, oven operates at 100% power.

Use to exit programming mode and stop
cooking during cooking cycle.

Use to start “Manual Time Entry” program
or restart interrupted cooking cycle. Use to
advance to next user option. Use to save
times and power levels when programming
pads.

Use to automatically increase the
programmed time for double quantities.

RCS511A / URCS511A

4-3

FEATURES

Window Door Screen

Electronic Control

Safety Door Lock System

CONTROL PANEL

Display

Some items in display can be seen but will not glow.

Pads

DIAL

QUICK SET

70%,

50%,

DEFROST

START

8

Use to enter cooking time.

Use to begin heating with preprogrammed
times and power levels.

Use to select power level. Oven can heat at
full or reduced power.

Use to start “Manual Time Entry” program
or restart interrupted cooking cycle. Use to
advance to next user option. Use to save
times and power levels when programming
pads.

9

0

RCS511MB / URS511MB

4-4

FEATURES

Window Door Screen

Electronic Control

Safety Door Lock System

CONTROL PANEL

Display

Some items in display can be seen but will not glow.

Pads

TIME ENTRY

Pads 1-0

HOLD 0%,
DEFROST 20%,
MEDUIM 50%,
MED-HI 70%

STOP/RESET

START

Use to enter heating time without changing
preprogrammed number pads.

Use to begin heating with preprogrammed
times and power levels or to enter times for
“Manual Time Entry” cooking.

Use to select power level. Oven can heat at
full or reduced power. If oven power level is
set to 0% oven does not heat for
programmed time. If no power level is
selected, oven operates at 100% power.

Use to exit programming mode and stop
cooking during cooking cycle.

Use to start “Manual Time Entry” program
or restart interrupted cooking cycle. Use to
advance to next user option. Use to save
times and power levels when programming
pads.

RFS511SW2A

4-5

OPERATING INSTRUCTIONS

FEATURES

CONTROL PANEL

Display

Some items in display can be seen but will not glow.

Pads

Use to enter heating time without changing
preprogrammed number pads.

Use to begin heating with preprogrammed

Use to enter times for “Manual Time Entry”

times and power levels or to enter times for
“Manual Time Entry” cooking.

cooking.

Use to select power level. Oven can heat at
full or reduced power. If oven power level is
set to 0% oven does not heat for
programmed time. If no power level is
selected, oven operates at 100% power.

Use to exit programming mode and stop
cooking during cooking cycle.

Use to start “Manual Time Entry” program

Use to automatically increase the
programmed time for double quantities.

or restart interrupted cooking cycle. Use to
advance to next user option. Use to save
times and power levels when programming
pads.

RFS511G

TIME ENTRY

DIAL

Pads 1-0

POWER
LEVEL

STOP/RESET

START

QTY2x

8
9
0

Window Door Screen

Electronic Control

Safety Door Lock System

POWER

LEVEL

QTY

2X

TIME

ENTRY

+

-

4-6

Cooking Displays

Shows when power is connected to oven. Open and close
door to clear.

READY shows when oven control will accept entries.
Appears after oven door is opened and closed.

33:33 shows heating time. When more than 1 heating stage is
programmed, total time for all stages displays.

COOK shows when oven is operating.
20 indicates the microwave power level used. If power level

does not show, oven is heating at 100% power.

Cooking DisplaysCooking DisplaysCooking Displays

Programming Displays

Indicates programming mode. See “Programming” section
of manual for programming procedure.

Indicates programming user options mode. See “User
Options” section of manual for programming procedure.

Programming DisplaysProgramming DisplaysProgramming Displays

4-7

Operation

Pads

1
2
3
4
5
6
7
8
9
0

Heating
Times

10 sec.
20 sec.
30 sec.
45 sec.
1 min.
1:30 min.
2 min.
3 min.
4 min.
5 min.

Pads

01
02
03
04
05
06
07
08
09
10

1. Press Pad.

CAUTION

Interrupting Operation

• Open oven door to interrupt operation. Oven fan
continues to operate. Close door and press START
pad to resume oven operation.

• Press STOP/RESET pad to interrupt operation.
Display continues to show countdown time. Press
START pad to resume oven operation and
countdown timing.

Canceling Mistakes

• If oven is operating, press STOP/RESET pad once to

stop oven, then again to clear display.

• If oven door is open and time shows in display, close
oven door and press STOP/RESET pad to clear
display.

Operating Preprogrammed Pads

Oven has 10 ~ 20 preprogrammed number pads.
Instructions are written for factory programmed ovens.
Ovens that are reprogrammed can respond differently
than described below.

1. Open oven door , place food in oven, and close oven

door

• If pad is not pressed in 30 seconds, open and close
oven door again.

2. Press desired number pad.

• Oven operates and time counts down.

3. Oven stops heating and oven signal sounds when
heating timing elapses.

Operating QTY 2X Pads

QTY

2X

2. Press desired number pad

• Example : press + = 18 sec.

Preprogrammed Times and Cook Level

All preprogrammed pads arrive set at full power.

Option: Single Digit

Pads

11
12
13
14
15
16
17
18
19
20

Heating
Times

10 sec.
20 sec.
30 sec.
45 sec.
1 min.
1:30 min.
2 min.
3 min.
4 min.
5 min.

Heating
Times

20 sec.
40 sec.
1 min.
1:30 min.
2 min.
3 min.
4 min.
6 min.
8 min.
10 min.

Option: Double Digit

Manual Time Entry

Manual Time Entry feature allows the operator to enter
time and power levels, and heat without changing the
preprogrammed pads.

1. Open oven door, place food in oven, and close door.

• Display shows "READY".

• If pad is not pressed in 30 seconds, open and close
oven door again.

2. Press TIME ENTRY pad.

• Display shows "00:00".

3. Press number pads to enter desired cooking time.

• For example, to heat for 2 minutes 30 seconds,

press 2, 3, and 0 pads.

4. Press desired power level pad to change power level.

• If a power level pad is not pressed, oven defaults to
100% power.

• For example, pressing MEDIUM 50% pad sets oven
to 50% power.

• Display shows current power level if other than 100
percent power.

5. Press START pad.

• Oven operates and time counts down.

6. Oven stops heating and oven signal sounds when
heating timing elapses.

QTY

2X

1

To avoid fire, do not dry newspapers or clothes in
microwave oven.

4-8

PROGRAMMING

Preprogrammed Number Pads

Oven has 10 preprogrammed number pads. Follow
instructions below to program heating times and power
levels for customized cooking.

1. Open oven door.
¥ If door is closed or STOP/RESET pad is pressed

before finishing programming sequence, oven exits
programming mode.

2. Press and hold pad 1 for approximately 5 seconds.
¥ After 5 seconds, signal sounds. Display shows

ÒPROGRAMÓ indicating program mode..

3. Press desired number pad.
¥ Display shows heating time, ÒCOOK LEVELÓ and

power level if other than 100 percent power.

4. Press number pads to enter desired cooking time.
¥ For example, to heat for 2 minutes 30 seconds,

press 2, 3, and 0 pads.

5. Press desired power level pad to change power level.
¥ If a power level pad is not pressed, oven defaults to

100% power.

¥ For example, pressing MEDIUM 50% pad sets oven

to 50% power.

¥ Display shows current power level if other than 100%

power.

6. Press START pad to save new heating time and
power level in oven memory.
¥ Repeat step 3-6 to program additional pads.

7. Press STOP/RESET pad or close oven door to exit
programming mode.

Multiple Heating Stages

Follow instructions below to program oven to perform 3
consecutive heating cycles without interruption.

1. Open oven door.
¥ If door is closed or STOP/RESET pad is pressed

before finishing programming sequence, oven exits
programming mode.

2. Press pad 1 for approximately 5 seconds.
¥ After 5 seconds, signal sounds.

3. Press desired number pad.
¥ Display shows heating time and preprogrammed

number.

4. Press number pads to enter desired cooking time.
¥ For example, to heat for 2 minutes 30 seconds,

5. Press desired power level pad to change power level.
¥ If a power level pad is not pressed, oven defaults to

100% power.

¥ For example, pressing MEDIUM 50% pad sets oven

to 50% power.

¥ Display shows current power level if other than 100

percent power.

6. Press TIME ENTRY pad
¥ Display briefly shows ÒSTAGE 2Ó . Then cook time

and power level for stage show in display.

¥ Repeat steps 5-6 to create additional stages.

7. Press START pad to save new heating time and
power level in oven memory.

8. Press STOP/RESET pad or close oven door to exit
programming mode.

4-9

User Options

Follow the instructions below to customized the
microwave ovenÕs operation. End-of-cycle signal,
maximum heating time and other options can be
changed to meeting your cooking needs.

1. Open oven door.
¥ If door is closed or STOP/RESET pad is pressed

before finishing programming sequence, oven exits
programming mode.

2. Press and hold pad 2 for approximately 5 seconds.
¥ After 5 seconds, signal sounds. Display shows

ÒOPTIONÓ.

3. Press number pad that matches desired option.
¥ ÒOPÓ represents optional program mode, first number

represents option number and second number
represents functions currently selected for option.

4. Press START pad to advance to next option.
See table for options.

5. Press number pad (0,1-3) to change option.

6. Press START pad to save changes.
¥ Repeat steps 4-6 to change additional options.

7. Press STOP/RESET pad or close oven door to exit
programming mode.

Numbered Pads Display Options (Factory Settings in Bold)

1

End of Cycle Beep

OP:10

OP:11
OP:12

3 second beep.

Continuous beep until door i s opened.
5 beep bursts unt il door is opened.

2

Speaker Volume

OP:20
OP:21
OP:22

OP:23

Eliminates beep.
Sets volume to low.
Sets volume to medium.

Sets vo lume to hi g h.

3

Key Beep

OP:30

OP:31

Prevents beep when pad is pressed.

Allows beep when pad is pressed.

4

Keyboard Enable

Window

OP:40
OP:41

OP:42

OP:43

15 seconds after oven door is opened, keyboard disabled.
30 seconds after oven door is opened, keyboard disabled.

1 minute after oven door is opened, keyboard disabled.

2 minutes after oven door is opened, keyboard disabled.

5

Add Time During

Heating

OP:50

OP:51

Prevents adding heating time while oven is heating.

Allows heating time to be changed while oven is heating when a memory pad
is pressed.

6

Reset Door Open

OP:60

OP:61

Allows oven to resume heating time countdown after door is opened during
cycle.

Cancels heating time count down after door is opened during cycle.

7

(some models)

Maximum Heating Time

OP:70

OP:71

Allows 60 minutes of heating time (some models).
Allows 10 minutes of heating time.

8

Manual Operation

OP:80

OP:81

Allows use of preprogrammed pads only.

Allows use of manual time entry and preprogrammed pads.

9

(some models)

Double Digit Operation

OP:90

OP:91

Allows 10 (0-9) preprogrammed pads .

Allows 100 (00-99) preprogrammed pads.

0

Clean Filter Message

OP:00

OP:01

OP:02
OP:03

Do not display message.
Display messag e for 24 hours every 7 days.
Display message for 24 ho urs every 30 days.
Display message for 24 ho urs every 90 days.

Optional Program Pad Option
Indicator Number Selected

SCHEMATIC DIAGRAM

4-10

CIRCUIT DESCRIPTION

4-11

RELAY 3

FUSE

SWITCH

MICOM CONTROLLER

SECONDARY

SWITCH

SWITCH

MONITOR

TRANS­FORMER

H.V.

INTERLLOCK

PRIMARY

INTERLLOCK

N

L

H.V.

INTERLLOCK

RELAY 3

SWITCH

MICOM CONTROLLER

TRANS-

FORMER

SECONDARY

SWITCH

MONITOR

PRIMARY

SWITCH

INTERLLOCK

FUSE

N

L

GENERAL DETAILS

• The low voltage transformer supplies the necessary
voltage to the micom controller when power cord is
plugged in.

• When the door is closed, the primary switch is ON, the

secondary switch is ON, and the monitor switch opens
(contact COM and NO).

WHEN SELECTING COOKING POWER
LEVEL AND TIME

• The micom controller memorizes the function you set.

• The time you set appears in the display window.

• Each indicator light turns on to indicate that the stage

has been set.

WHEN TOUCHING THE START PAD

• The coil of the relay is energized by the micom

controller.

• Power input is supplied to the high voltage transformer

through the fuse to primary switch and realy 3.

• Stirrer fan rotates.

• A high voltage of approximately 2100 volts AC is
generated in the secondary of the high voltage
transformer which is increased by the action of the high
voltage diode and charging of the high voltage
capacitor.

• The negative 4,000 Volts DC is applied to the filament
of the magnetron.

WHEN THE OVEN IS SET AT ANY LEVEL
EXCEPT MAXIMUM.

• The micom controller controls the ON-OFF time of
relay 3 by the applied signal to vary the average output
power of microwave oven as POWER LEVEL.
(refer to page 1-1)

• One complete cycle of relay 3 is 12.

WHEN THE DOOR IS OPENED DURING
COOKING

• Both the primary switch and relay 3 cut off the primary
winding voltage of the high voltage transformer.

• ON-OFF of relay 3 is coupled electrically with opening
and closing of the secondary switch.

• When the door is opened, the secondary switch is
opened and when the door is closed, the secondary
switch is closed.

• The cooking time stops counting down.

• Relay stops functioning.

• As the door is opened, if the contact of primary switch

and relay 3 and/or secondary switch fail to open,

the fuse opens due to the large current surge caused by

the monitor switch activation, which in turn stops magnetron

oscillation.

• The fan motor rotates and cools the magnetron by
blowing the air (coming from the intake on the base­plate).

• The air is also directed into the oven to exhaust the
vapor in the oven through the upper plate.

• Cooking time starts counting down.

• 3.3 volts AC is generated from the filament winding of
the high voltage transformer. This 3.3 volts is applied to
the magnetron to heat the magnetron filament through
two noise-preventing choke coils.

CAUTIONS

¥ Be sure to check microwave leakage prior to

servicing the oven if the oven is operative prior to
servicing.

¥ The service personnel should inform the

manufacturer, importer, or assembler of any
certified oven unit found to have a microwave
emission level in excess of 5 mW/cm2and should

repair any unit found to have excessive emission levels
at no cost to the owner and should ascertain the cause
of the excessive leakage. The service personnel
should instruct the owner not to use the unit until the
oven has been brought into compliance.

¥ If the oven operates with the door open, the service

personnel should:

- Tell the user not to operate the oven.

- Contact the manufacturer and CDRH
(Center for Devices and Radiological Health)

immediately.

NOTE: Address on CDRH

Office of Compliance(HFZ-312)
Center for Devices and Radiological
Healthe 1390, Piccard Drive,
Rockville. MD 20850

¥ The service personnel should check all surface and

vent openings for microwave leakage.

¥ Check for microwave leakage after every servicing. The

power density of the microwave radiation leakage
emitted by the microwave oven should not exceed
4 mW/cm2. Always start measuring of an unknown field
to assure safety for operating personnel from radiation
leakage.

MEASURING MICROWAVE ENERGY
LEAKAGE

¥ Pour 275±15cc of 20±5¡C(68±9¡F) water in a beaker

which is graduated to 600 cc, and place the beaker
on the center of the turntable.

¥ Set the energy leakage monitor to 2,450 MHz and

use it following the manufacturer's recommended
test procedure to assure correct result.

¥ When measuring the leakage, always use the 2-inch

(5cm) spacer supplied with the probe.
¥ Operate the oven at its maximum output.
¥ Measure the microwave radiation using and

electromagnetic radiation monitor by holding the

probe perpendicular to the surface being measured

Move probe along shaded area

Probe scanning speed

Less than 2.5 cm/sec

( 1in/sec)

5-1

SERVICE INFORMATION

TOOLS AND MEASURING INSTRUMENTS

MICROWAVE LEAKAGE TEST

NECESSARY TOOLS

Tools normally used for TV servicing are sufficient.
Standard tools are listed below.

¥ Diagonal pliers
¥ Long nose pliers
¥ Phillips screwdriver
¥ Flat blade screwdriver
¥ Wrench (size 5mm)
¥ Nutdriver (size 5mm)
¥ Adjustable wrench
¥ Soldering iron
¥ Solder
¥ Vinyl insulation tape
¥ Polishing cloth

NECESSARY MEASURING INSTRUMENTS

¥ TESTER (VOLTS-DC, AC, Ohmmeter)
¥ Microwave survey meter

- Holaday HI-1500
HI-1501

- Narda 8100

8200
¥ Inch scale
¥ 600 cc non conductive material beaker (glass or plastic),

inside diameter: approx. 8.5 cm (3

1

/2 in.)

¥ Cylindrical and made of borosilicate glass vessel.

max. thickness: 3 mm
outside diameter: approx. 190mm
height: approx. 90mm

¥ Glass thermometer: 100¡C or 212¡F (1 deg scale)

MEASUREMENT WITH OUTER CASE
REMOVED

¥ 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. (Circled area of Fig. below)

- Around the magnetron

- The waveguide

MEASUREMENT WITH A FULLY
ASSEMBLED OVEN

¥ After all components, including the outer case, are fully

assembled, measure for microwave energy leakage
around the door viewing window, the exhaust opening,
and air inlet openings.

¥ Microwave energy leakage must not exceed the values

prescribed below.

NOTE: Leakage with the outer case removed less than

5 mW/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 2 mW/cm.sq.

NOTES WHEN MEASURING

¥ Do not exceed meter full scale deflection.
¥ The test probe must be removed no faster than

1 inch/sec (2.5 cm/sec) along the shaded area,
otherwise a false reading may result.

¥ 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.

¥ When testing near a corner of the door, keep the probe

perpendicular to the surface making sure the probe
horizontally along the oven surface; this may possibly
cause probe damage.

RECORD KEEPING AND NOTIFICATION
AFTER MEASUREMENT

¥ 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.

¥ The microwave energy leakage should not be more

than 4 mW/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.

¥ At least once a year, have the electromagnetic energy

leakage monitor checked for calibration by its
manufacturer.

5-2

WARNING : AVOID CONTACTING ANY

HIGH VOLTAGE PARTS

MEASUREMENT OF MICROWAVE POWER OUTPUT

securing
screw

Remove the screw

Lift up and pull out control panel

• Microwave power output measurement is made with
the microwave oven supplied at its rated voltage and
operated at its maximum microwave power setting with
a load of (1000±5) g of potable water.

• The water is contained in a cylindrical borosilicate glass
vessel having a maximum material thickness of 3 mm
and an outside diameter of approximately 190mm.

• The oven and the empty vessel are at ambient
temperature prior to the start of the test.

• The initial temperature (T1) of the water is (10±2)°C It
is measured immediately before the water is added to
the vessel. After addition of the water to the vessel,
the load is immediately placed on the center of the
ceramic plate which is in the lowest position and the
microwave power switched on.

• The time T for the temperature of the water to rise by a
value ∆ T of (10±2)°K is measured, where T is the time

in seconds and ∆T is the temperature rise. The initial
and final water temperatures are selected so that the
maximum difference between the final water
temperature and the ambient temperature is 5°K.

• The microwave power output P in watts is calculated
from the following formula :

is measured while the microwave generator is
operating at full power. Magnetron filament heat-up
time is not included. (about 3 sec)

• The water is stirred to equalize temperature throughout
the vessel, prior to measuring the final water
temperature.

• Stirring devices and measuring instruments are
selected in order to minimize addition or removal of
heat.

DISASSEMBLY AND ADJUSTMENT

P =

WATER LOAD

4187 x (∆T)

T

CERAMIC PLATE

A. OUTER CASE REMOVAL

1) Disconnect the power supply cord from the outlet.

2) Remove the screws from the rear of the case.
The outer case must be moved backward to be lifted
off.

B. POWER SUPPLY CORD

1) Remove the outer case.

2) Disconnect two terminals, and remove one screw of
the ground terminal.

C. CONTROL PANEL ASSEMBLY RMOVAL

1) Open the door.

2) Remove the screw for securing the control panel.

3) Disconnect the leadwire from RELAY (RY3)

of the PCB

4) Disconnect the leadwire from connector (CN1) of the
PCB SUB ASS’Y.

5) Lift up and pull out control panel assembly carefully

from the cavity.

CAUTION: DISCHARGE THE HIGH VOLTAGE

SUB ASS’Y.

CAPACITOR BEFORE SERVICING

(refer to page 2-1)

5-3

D. PCB ASSEMBLY REMOVAL

1) Remove the control panel assembly from the
cavity. (Refer to control panel assembly removal
on previous page.)

2) Remove screws which hold the PCB SUB ASSÕY to
the control panel.

3) Disconnect the flat cable from the PCB SUB
ASSÕY and take off the PCB SUB ASSÕY

E. DOOR MAIN 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

by screwdriver.

3) Lift up and push 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 4 mW/cm2. (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.

5-4

Remove door

Remove choke cover

SpacerSpacerSpacerSpacer

Control Panel

PCB Sub Asm

Remove door

Remove choke cover

Door seal plate

5-5

F. MAGNETRON REMOVAL

1) Disconnect the leadwire from the magnetron.

2) Carefully remove the mounting screws holding the
magnetron and the waveguide.

3) Remove the magnetron ASS’Y until the tube is
clear from the waveguide.

NOTE:

1. When removing the magnetron, make sure its
dome does not hit any adjacent parts, or it may be
damaged.

2. When replacing the magnetron, be sure to install
the magnetron gasket in the correct position and be
sure that the gasket is in good condition.

3. After replacing the magnetron, check for microwave
leakage with a survey meter around the
Microwave energy must be below the limit of 5

mW/cm

2

. (With a 275 ml. water load).

Make sure that gasket is rigidly attached to the
magnetron. To prevent microwave leakage, tighten

the mounting screws properly, making sure there is
no gap between the waveguide and the magnetron.

G. REMOVING THE STIRRER
FAN MOTOR

1) Disconnect the leadwire from the stirrer fan motor
terminals.

2) Remove the screw securing the stirrer fan motor to
the oven cavity ASS’Y

3) After repairing the motor, replace the removed
leadwire.

NOTE:

1.

Remove the wire lead from the stirrer fan motor
VERY CAREFULLY.

2. Be sure to grasp the connector, not the wires, when

removing.

Magnetron

Stirrer fan motor

H. HIGH VOLTAGE TRANSFORMER

REMOVAL

1) Discharge the high voltage capacitor.

2) Disconnect the leadwire from magnetron, high voltage
transformer, and capacitor.

3) Remove the screw holding the high voltage
transformer to the bottom plate.

I. BLOWER MOTOR ASSEMBLY REMOVAL

1) Disconnect the leadwire from blower motor.

2) Remove the two screws holding the blower motor

to the bottom plate.

J. HIGH VOLTAGE CAPACITOR AND

DIODE REMOVAL

1) Discharge the high voltage capacitor.

2) Disconnect the leadwire from

high voltage capacitor.

3) Remove the screw holding the

high voltage diode

earth screw.

4) Remove the screw holding the high voltage capacitor
bracket.

K. INTERLOCK SYSTEM

1) INTERLOCK MECHANISM
The door lock mechanism is a device which has

been specially designed to eliminate completely
microwave activity when the door is opened during
cooking and thus to prevent the danger resulting
from the microwave leakage.

2) MOUNTING OF THE PRIMARY/MONITOR/

SECONDARY SWITCHES TO THE LATCH
BOARD

3) INSTALLATION AND ADJUSTMENT OF THE

LATCH BOARD TO THE OVEN ASSEMBLY

• Mount the latch b oard to the oven assembly.

• Adjust the latch board in the arrow direction so that

oven door will not have any play in it when the door
is closed.

• Tighten the mounting screw.

• Check for play in the door by pushing the door

release button. Door movement should be less
than 0.5 mm. (1/64 inch)

Don't push the door release button while making this
adjustment. Make sure that the latch moves
smoothly after adjustment is completed and that the
screws are tight. Make sure the primary, monitor,
and secondary switches operate properly by
following the continuity test procedure.

PRIMARY
SWITCH

ADJUSTMENT
DIRECTION

MONITOR
SWITCH

SECONDARY
SWITCH

Bottom plate

H.V. Transformer

H.V. Capacitor

Blower motor assembly

5-6

A. PRIMARY INTERLOCK SWITCH TEST

When the door release button is depressed slowly
with the door closed, an audible click should be
heard at the same time or successively at
intervals. When the button is released slowly, the
latches should activate the switches with an
audible click.
If the latches do not activate the switches when
the door is closed, the switches should be a
adjusted in accordance with the adjustment
procedure. Disconnect the wire lead from the
primary switch. Connect the ohmmeter leads to
the common (COM) and normally open (NO)
terminal of the switch. The meter should indicate
an open circuit in the door open condition.
When the door is closed, the meter should
indicate a closed circuit.
When the primary switch operation is abnormal,
make the necessary adjustment or replace the
switch only with the same type of switch.

B. SECONDARY INTERLOCK SWITCH TEST

Disconnect the wire lead from the secondary
switch.
Connect the ohmmeter leads to the common
(COM) and normally open (NO) terminals of the
switch. The meter should indicate a open circuit in
the door open condition. When the door is closed,
meter should indicate an closed circuit. When the
secondary switch operation is abnormal, make the
necessary adjustment or replace the switch only
with the same type of switch.

C. MONITOR SWITCH TEST

Disconnect the wire lead from the monitor switch.
Connect the ohmmeter leads to the common
(COM) and normally closed (NC) terminals of the
switch. The meter should indicate closed circuit in
the door open condition. When the door is closed,
meter should indicate an open circuit. When the
monitor switch operation is abnormal, replace with
the same type of switch.

NOTE: After repairing the door or the interlock
system, it is necessary to do this continuity
test before operating the oven.

5-7

WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION

EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS.

TYPE NO. SZM-V 21-FC-93 FOR PRIMARY SWITCH
TYPE NO. SZM-V 16-FD-62 OR V-16-2C 25 FOR MONITOR SWITCH
TYPE NO. SZM-V 16-FD-63 OR V-16-3C 25 FOR SECONDARY SWITCH

COMPONENTS TEST PROCEDURE RESULTS

SWITCHES Check for continuity of the Door Door
(Wire leads removed) switch with an Ohm-meter open closed

Primary
Switch

Monitor
Switch

Secondary
Switch

NOTE : After checking for the continuity of switches, make sure that they are

connected correctly.

INTERLOCK CONTINUITY TEST

COM

COM

COM

NO

NC

NO

5-8

CAUTIONS

1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE
OUTER CASE FROM THE UNIT. PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH
VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE
HIGH VOLTAGE TRANSFORMER. (SEE PAGE 2-1)

2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER
OF WATER IN CONTAINER) IN THE OVEN.

COMPONENTS TEST PROCEDURE RESULTS

HIGH VOLTAGE
TRANSFORMER
(Wire leads removed)

MAGNETRON
(Wire leads removed)

1. Measure the resistance.
(Ohm-meter scale: Rx1 and Rx100)
¥ Primary winding
¥ Secondary winding
¥ Filament winding

2. Measure the resistance.
(Ohm-meter scale: Rx1000)
¥ Primary winding to ground
¥ Filament winding to ground

1. Measure the resistance.
(Ohm-meter scale: Rx1)
¥ Filament terminal

2. Measure the resistance.
(Ohm-meter scale: Rx1000)
¥ Filament to chassis

Approx.: 1.81 ~ 2.4 ohm
Approx.: 100 ~ 125 ohm

Less than: 1 ohm

Normal: Infinite
Normal: Infinite

Normal: Less than 1 ohm

Normal: Infinite

COMPONENT TEST PROCEDURE

FILAMENT
WINDING

SECONDARY
TERMINAL

PRIMARY
TERMINAL

5-9

COMPONENTS TEST PROCEDURE RESULTS

HIGH VOLTAGE
CAPACITOR

HIGH VOLTAGE
DIODE

NOTE :
Some inexpensive meters
may indicate infinite
resistance in both direction.

Measure the resistance.
(Ohm-meter scale: Rx1000)
¥ Terminal to terminal.

Measure the resistance.
(Ohm-meter scale: Rx1000)
¥ Terminal to case.

Measure the continuity (Forward).
(Ohm-meter scale: Rx10000)

Measure the continuity (Reverse).
(Ohm-meter scale: Rx10000)

Normal: Momentarily indicates

several ohms, and
then gradually returns
to infinite.

Normal: Infinite.

Normal: Continuity.
Abnormal: Infinite.

Normal: Infinite.
Abnormal: Continuity.

NOTE: When testing the magnetron, be sure to install the magnetron gasket

in the correct position and be sure that the gasket is in good condition.

Antenna

Gasket

Chassis

Filament

COMPONENTS TEST PROCEDURE RESULTS

RELAY 3

BLOWER MOTOR

(Wire leads removed)

Check for continuity of relay 3 an
ohm-meter.
(Remove wire leads from relay 3 and
operate the unit.)

Relay 3

Measure the resistance.
(Ohm-meter scale: R x 100)

POWER
LEVEL

1 3 sec 9 sec
2 4 sec 8 sec
3 5 sec 7 sec
4 6 sec 6 sec
5 7 sec 7 sec
6 8 sec 4 sec
7 9 sec 3 sec
8 10 sec 2 sec
9 11 sec 1 sec

10 12 sec 0 sec

Normal: Approx. 72~82 ohm

Abnormal: Infinite or several

K-ohm.

STIRRER

MOTOR
(Wire leads removed)

NOTE : • A MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS

SERVICED FOR ANY REASON.

• MAKE SURE THE WIRE LEADS ARE IN THE CORRECT POSITION.

• WHEN REMOVING THE WIRE LEADS FROM THE PARTS, BE SURE TO GRASP THE
CONNECTOR, NOT THE WIRES.

Measure the resistance.
(Ohm-meter scale: R x 1000)

Normal: Approx. 12.8~13.5 kohm

Abnormal: Infinite or several

ohm.

5-10

TROUBLE SHOOTING

WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF
THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE
MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL.

5-11

CAUTIONS

1. Check grounding before checking for trouble.

2. Be careful of the high voltage circuit.

3. Discharge the high voltage capacitor. (See page 2-1)

4. When checking the continuity of the switches or of the high voltage transformer, disconnect one lead wire
from these parts and then check continuity with the AC plug removed. To do otherwise may result in a
false reading or damage to your meter.

5. Do not touch any part of the circuit on the PCB since static electric discharge may damage this control
panel.

Always touch yourself to ground while working on this panel to discharge any static charge built up in your

body. (Micom model only)

TROUBLE SHOOTING

WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF
THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE
MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL.

CAUTIONS

1. Check grounding before checking for trouble.

2. Be careful of the high voltage circuit.

3. Discharge the high voltage capacitor. (See page 2-1)

4. When checking the continuity of the switches or of the high voltage transformer, disconnect one lead wire
from these parts and then check continuity with the AC plug removed. To do otherwise may result in a
false reading or damage to your meter.

5. Do not touch any part of the circuit on the PCB since static electric discharge may damage this control
panel.
Always touch yourself to ground while working on this panel to discharge any static charge built up in your
body. (Micom model only)

CONDITION

Microwave oven

does not work.

Inserting many plugs into one
outlet and using them at the
same time.
(blown fuse or breaker)

Microwave oven plug is not
inserted tightly.

Output power is too low. Low AC input voltage.

Food temperature is too low.

Display "CALL SERVICE"

Using metallic ware and
allowing it to touch the oven
wall.

Sparks occur.

Inconsistent intensity of
microwave by their
characteristics.

1. Use plastic wrap or lid.

2. Stir once or twice while
cooking soup, cocoa or
milk, etc.

Uneven cooking.

Ceramic ware trimmed in
gold or silver powder is used.

Avoid using other electrical
appliances when you use the
microwave oven.

Insert microwave oven plug
securely.

Use the microwave oven at
adequate line voltage.

This may not be a defect.
It is possible that the food
should be cooked for a
longer time period.

Do not use metallic ware for
cooking except that noted in
the cooking guide.

Do not use any type of
cookware with metallic
trimming.

CAUSE REMEDY

This may be cause
incomplete connect to H.V.
transformer.

TROUBLE SHOOTING

WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF
THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE
MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL.

CAUTIONS

1. Check grounding before checking for trouble.

2. Be careful of the high voltage circuit.

3. Discharge the high voltage capacitor. (See page 2-1)

4. When checking the continuity of the switches or of the high voltage transformer, disconnect one lead wire
from these parts and then check continuity with the AC plug removed. To do otherwise may result in a
false reading or damage to your meter.

5. Do not touch any part of the circuit on the PCB since static electric discharge may damage this control
panel.
Always touch yourself to ground while working on this panel to discharge any static charge built up in your
body. (Micom model only)

CONDITION

Microwave oven

does not work.

Inserting many plugs into one
outlet and using them at the
same time.
(blown fuse or breaker)

Microwave oven plug is not
inserted tightly.

Output power is too low. Low AC input voltage.

Food temperature is too low.

Display "CALL SERVICE"

Using metallic ware and
allowing it to touch the oven
wall.

Sparks occur.

Inconsistent intensity of
microwave by their
characteristics.

1. Use plastic wrap or lid.

2. Stir once or twice while
cooking soup, cocoa or
milk, etc.

Uneven cooking.

Ceramic ware trimmed in
gold or silver powder is used.

Avoid using other electrical
appliances when you use the
microwave oven.

Insert microwave oven plug
securely.

Use the microwave oven at
adequate line voltage.

This may not be a defect.
It is possible that the food
should be cooked for a
longer time period.

Do not use metallic ware for
cooking except that noted in
the cooking guide.

Do not use any type of
cookware with metallic
trimming.

CAUSE REMEDY

This may be cause
incomplete connect to H.V.
transformer.

TROUBLE SHOOTING

WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF
THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE
MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL.

CAUTIONS

1. Check grounding before checking for trouble.

2. Be careful of the high voltage circuit.

3. Discharge the high voltage capacitor. (See page 2-1)

4. When checking the continuity of the switches or of the high voltage transformer, disconnect one lead wire
from these parts and then check continuity with the AC plug removed. To do otherwise may result in a
false reading or damage to your meter.

5. Do not touch any part of the circuit on the PCB since static electric discharge may damage this control
panel.
Always touch yourself to ground while working on this panel to discharge any static charge built up in your
body. (Micom model only)

CONDITION

Microwave oven

does not work.

Inserting many plugs into one
outlet and using them at the
same time.
(blown fuse or breaker)

Microwave oven plug is not
inserted tightly.

Output power is too low. Low AC input voltage.

Food temperature is too low.

Display "CALL SERVICE"

Using metallic ware and
allowing it to touch the oven
wall.

Sparks occur.

Inconsistent intensity of
microwave by their
characteristics.

1. Use plastic wrap or lid.

2. Stir once or twice while
cooking soup, cocoa or
milk, etc.

Uneven cooking.

Ceramic ware trimmed in
gold or silver powder is used.

Avoid using other electrical
appliances when you use the
microwave oven.

Insert microwave oven plug
securely.

Use the microwave oven at
adequate line voltage.

This may not be a defect.
It is possible that the food
should be cooked for a
longer time period.

Do not use metallic ware for
cooking except that noted in
the cooking guide.

Do not use any type of
cookware with metallic
trimming.

CAUSE REMEDY

This may be cause
incomplete connect to H.V.
transformer.

TROUBLE SHOOTING

WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF
THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE
MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL.

CAUTIONS

1. Check grounding before checking for trouble.

2. Be careful of the high voltage circuit.

3. Discharge the high voltage capacitor. (See page 2-1)

4. When checking the continuity of the switches or of the high voltage transformer, disconnect one lead wire
from these parts and then check continuity with the AC plug removed. To do otherwise may result in a
false reading or damage to your meter.

5. Do not touch any part of the circuit on the PCB since static electric discharge may damage this control
panel.
Always touch yourself to ground while working on this panel to discharge any static charge built up in your
body. (Micom model only)

CONDITION

Microwave oven

does not work.

Inserting many plugs into one
outlet and using them at the
same time.
(blown fuse or breaker)

Microwave oven plug is not
inserted tightly.

Output power is too low. Low AC input voltage.

Food temperature is too low.

Display "CALL SERVICE"

Using metallic ware and
allowing it to touch the oven
wall.

Sparks occur.

Inconsistent intensity of
microwave by their
characteristics.

1. Use plastic wrap or lid.

2. Stir once or twice while
cooking soup, cocoa or
milk, etc.

Uneven cooking.

Ceramic ware trimmed in
gold or silver powder is used.

Avoid using other electrical
appliances when you use the
microwave oven.

Insert microwave oven plug
securely.

Use the microwave oven at
adequate line voltage.

This may not be a defect.
It is possible that the food
should be cooked for a
longer time period.

Do not use metallic ware for
cooking except that noted in
the cooking guide.

Do not use any type of
cookware with metallic
trimming.

CAUSE REMEDY

This may be cause
incomplete connect to H.V.
transformer.

1. Incomplete segments.
¥ Segment missing.
¥ Partial segment missing.
¥ Digit flickering (NOTE: Slight flickering is normal.)

2. Colon does not turn on or blink.

3. A distinct change in the brightness of one or more numbers in display.

4. One or more digits in the display are not lighting.

5. Display indicates a number different from one touched, for example, key in 5 and 3 appears in the display.

6. Specific numbers (for example 7 or 9) will not display when key pad is touched.

7. Display does not count down with time blinking or up with clock operation.

8. Display obviously jumps in time while counting down.

9. Display counts down too fast while cooking.

10. Each indicator light does not turn on after setting cooking cycle.

11. Display time of day does not reappear when cooking is finished.

5-12

(TROUBLE 1)

The following visual conditions indicate a probable defective control circuit.

CONDITION CHECK RESULT CAUSE REMEDY

1. No input can be
programmed.

Continuity

No continuity

Defective PCB
assembly.

Loose
connection.

Replace PCB
assembly.

Connect them
tightly.

Check the conn­ection between
membrane key
assembly and
PCB assembly.

2. Some inputs
cannot be
programmed.

3. Display shows a
number or figure
different from one
touched.

4. Random
programming
when touching
other pads.

5. Display is fixed
at some figure
and can not
accept any
input.

Everything works
as specified.

Still have trouble.

Defective key
membrane
assembly.

Defective PCB
assembly.

Replace key
membrane
assembly.

Replace PCB
assembly.

Replace key
membrane
assembly and
check operation.

5-13

CONDITION

CONDITION CHECK RESULT CAUSE REMEDY

1. Fuse blows. Continuity.

No continuity.

Continuity.

Shorted contact at
the primary switch.

Replace fuse,
primary, monitor,
secondary
switches, and

RELAY(RY3 )
of P.C.B Assembly.

No continuity.

Malfunction of the
monitor switch.

Replace fuse,

primary, monitor,
secondary
switches, and

RELAY(RY3)

Check continuity
of monitor
switch (with
door closed).

Check continuity
of primary
switch (with
door opened).

Replace fuse

Continuity.

Malfunction of
secondary switch.

Replace fuse,
primary, monitor,
secondary
switches, and
RELAY(RY3)

of P.C.B Assembly.

No continuity.

Check continuity
of secondary
switch (with
door opened).

2. Fuse does not
blow.

No continuity.

Continuity.

No continuity.

Defective power
supply cord.

Replace power
supply cord.

Defective
thermostat.

Replace
thermostat.

Check continuity
of thermostat.

Check continuity
of power supply
cord.

(TROUBLE 2)

Oven does not operate at all, Display window does not display any figures,
and no input is accepted.

NOTE : All these switches must be replaced at the same time. Refer to page 5-7, 5-8

Normal.

Normal.

Abnormal.

Defective high
voltage capacitor.

Replace high
voltage capacitor.

Set is good condition
(defective fuse only)

Fuse blows again

Defective high volt­age transformer.

Replace high volt­age transformer.

Disconnect one
side of the wire
lead connected
from transformer
to the high voltage
capacitor and
operate the unit.

Measure to
resistance high
voltage capacitor
(refer to page 5-9)

1. Fuse blows. Continuity.

No continuity.

Continuity.

Shorted contact at
the primary switch.

Replace fuse,
primary, monitor,
secondary
switches, and

No continuity.

Malfunction of the
monitor switch.

Replace fuse,

primary, monitor,
secondary
switches, and

Check continuity
of monitor
switch (with
door closed).

Check continuity
of primary
switch (with
door opened).

Replace fuse

Continuity.

Malfunction of
secondary switch.

Replace fuse,
primary, monitor,
secondary
switches, and

No continuity.

Check continuity
of secondary
switch (with
door opened).

2. Fuse does not
blow.

No continuity.

Continuity.

No continuity.

Defective power
supply cord.

Replace power
supply cord.

Defective
thermostat.

Replace
thermostat.

Check continuity
of thermostat.

Check continuity
of power supply
cord.

Oven does not operate at all, Display window does not display any figures,
and no input is accepted.

Normal.

Normal.

Abnormal.

Defective high
voltage capacitor.

Replace high
voltage capacitor.

Set is good condition
(defective fuse only)

Fuse blows again

Defective high volt­age transformer.

Replace high volt­age transformer.

Disconnect one
side of the wire
lead connected
from transformer
to the high voltage
capacitor and
operate the unit.

Measure to
resistance high
voltage capacitor
(refer to page 5-9)

1. Fuse blows. Continuity.

No continuity.

Continuity.

Shorted contact at
the primary switch.

Replace fuse,
primary, monitor,
secondary
switches, and

No continuity.

Malfunction of the
monitor switch.

Replace fuse,

primary, monitor,
secondary
switches, and

Check continuity
of monitor
switch (with
door closed).

Check continuity
of primary
switch (with
door opened).

Replace fuse

Continuity.

Malfunction of
secondary switch.

Replace fuse,
primary, monitor,
secondary
switches, and

No continuity.

Check continuity
of secondary
switch (with
door opened).

2. Fuse does not
blow.

No continuity.

Continuity.

No continuity.

Defective power
supply cord.

Replace power
supply cord.

Defective
thermostat.

Replace
thermostat.

Check continuity
of thermostat.

Check continuity
of power supply
cord.

Normal.

Normal.

Abnormal.

Defective high
voltage capacitor.

Replace high
voltage capacitor.

Set is good condition
(defective fuse only)

Fuse blows again

Defective high volt­age transformer.

Replace high volt­age transformer.

Disconnect one
side of the wire
lead connected
from transformer
to the high voltage
capacitor and
operate the unit.

Measure to
resistance high
voltage capacitor
(refer to page 5-9)

1. Fuse blows. Continuity.

No continuity.

Continuity.

Shorted contact at
the primary switch.

Replace fuse,
primary, monitor,
secondary
switches, and

No continuity.

Malfunction of the
monitor switch.

Replace fuse,

primary, monitor,
secondary
switches, and

of P.C.B Assembly.

Check continuity
of monitor
switch (with
door closed).

Check continuity
of primary
switch (with
door opened).

Replace fuse

Continuity.

Malfunction of
secondary switch.

Replace fuse,
primary, monitor,
secondary
switches, and

No continuity.

Check continuity
of secondary
switch (with
door opened).

2. Fuse does not
blow.

No continuity.

Continuity.

No continuity.

Defective power
supply cord.

Replace power
supply cord.

Defective
thermostat.

Replace
thermostat.

Check continuity
of thermostat.

Check continuity
of power supply
cord.

Normal.

Normal.

Abnormal.

Defective high
voltage capacitor.

Replace high
voltage capacitor.

Set is good condition
(defective fuse only)

Fuse blows again

Defective high volt­age transformer.

Replace high volt­age transformer.

Disconnect one
side of the wire
lead connected
from transformer
to the high voltage
capacitor and
operate the unit.

Measure to
resistance high
voltage capacitor
(refer to page 5-9)

5-14

CONDITION

CONDITION CHECK RESULT CAUSE REMEDY

1. Setting time
does not count
down when
touching START
pad.

2. Blower motor
or oven lamp
do not turn on.

No continuity.

Continuity.

Continuity

Defective PCB
assembly.

Loose connection.

Replace PCB
assembly.

Connect them
tightly.

No continuity

Abnormal

Check blower motor.

Defective blower motor. Replace blower motor.

Abnormal

Normal

Check oven lamp.

Defective oven lamp. Replace oven lamp.

Defective
secondary switch.

Replace
secondary switch.

Check continuity
of secondary
switch (with
door closed).

Check the con­nection between
CN1 connector
and PCB
assembly.

(TROUBLE 3)

Display shows all figures set, but oven does not start cooking while desired

program times are set and START pad is touched.

(TROUBLE 4) Oven seems to be operating but little heat is produced in oven load.

NOTE :

Simple test of power output-conducted by heating one liter water for one min. if available.
Minimum 8.5°C temperature rise is normal condition.

CONDITION CHECK RESULT CAUSE REMEDY

Output is low

Lower than 90% of
rating voltage.

Normal

Abnormal

Defective PCB
assembly.

Replace PCB
assembly.

Normal

Abnormal

Measure the
output power.

Defective
magnetron.

Replace
magnetron.

Decrease in power
source voltage
with load.

Suggest customer
contact local
electric power
utility co. or
qualified
electrician.

Check the
power source
voltage.

Disconnect the
wire leads from
relay 3
and check
on and off

time

with multitester.

CONDITION CHECK RESULT CAUSE REMEDY

1. Setting time
does not count
down when
touching START
pad.

2. Blower motor
or oven lamp
do not turn on.

No continuity.

Continuity.

Continuity

Defective PCB
assembly.

Loose connection.

Replace PCB
assembly.

Connect them
tightly.

No continuity

Abnormal

Check blower motor.

Defective blower motor. Replace blower motor.

Abnormal

Normal

Check oven lamp.

Defective oven lamp. Replace oven lamp.

Defective
secondary switch.

Replace
secondary switch.

Check continuity
of secondary
switch (with
door closed).

Check the con­nection between
CN1 connector
and PCB
assembly.

(TROUBLE 3)

Display shows all figures set, but oven does not start cooking while desired

program times are set and START pad is touched.

(TROUBLE 4) Oven seems to be operating but little heat is produced in oven load.

CONDITION CHECK RESULT CAUSE REMEDY

Output is low

Lower than 90% of
rating voltage.

Normal

Abnormal

Defective PCB
assembly.

Replace PCB
assembly.

Normal

Abnormal

Measure the
output power.

Defective
magnetron.

Replace
magnetron.

Decrease in power
source voltage
with load.

Suggest customer
contact local
electric power
utility co. or
qualified
electrician.

Check the
power source
voltage.

CONDITION CHECK RESULT CAUSE REMEDY

1. Setting time
does not count
down when
touching START
pad.

2. Blower motor
or oven lamp
do not turn on.

No continuity.

Continuity.

Continuity

Defective PCB
assembly.

Loose connection.

Replace PCB
assembly.

Connect them
tightly.

No continuity

Abnormal

Check blower motor.

Defective blower motor. Replace blower motor.

Abnormal

Normal

Check oven lamp.

Defective oven lamp. Replace oven lamp.

Defective
secondary switch.

Replace
secondary switch.

Check continuity
of secondary
switch (with
door closed).

Check the con­nection between
CN1 connector
and PCB
assembly.

(TROUBLE 3)

Display shows all figures set, but oven does not start cooking while desired

program times are set and START pad is touched.

(TROUBLE 4) Oven seems to be operating but little heat is produced in oven load.

CONDITION CHECK RESULT CAUSE REMEDY

Output is low

Lower than 90% of
rating voltage.

Normal

Abnormal

Defective PCB
assembly.

Replace PCB
assembly.

Normal

Abnormal

Measure the
output power.

Defective
magnetron.

Replace
magnetron.

Decrease in power
source voltage
with load.

Suggest customer
contact local
electric power
utility co. or
qualified
electrician.

Check the
power source
voltage.

CONDITION CHECK RESULT CAUSE REMEDY

1. Setting time
does not count
down when
touching START
pad.

2. Blower motor
or oven lamp
do not turn on.

No continuity.

Continuity.

Continuity

Defective PCB
assembly.

Loose connection.

Replace PCB
assembly.

Connect them
tightly.

No continuity

Abnormal

Check blower motor.

Defective blower motor. Replace blower motor.

Abnormal

Normal

Check oven lamp.

Defective oven lamp. Replace oven lamp.

Defective
secondary switch.

Replace
secondary switch.

Check continuity
of secondary
switch (with
door closed).

Check the con­nection between
CN1 connector
and PCB
assembly.

(TROUBLE 3)

Display shows all figures set, but oven does not start cooking while desired

program times are set and START pad is touched.

(TROUBLE 4) Oven seems to be operating but little heat is produced in oven load.

CONDITION CHECK RESULT CAUSE REMEDY

Output is low

Lower than 90% of
rating voltage.

Normal

Abnormal

Defective PCB
assembly.

Replace PCB
assembly.

Normal

Abnormal

Measure the
output power.

Defective
magnetron.

Replace
magnetron.

Decrease in power
source voltage
with load.

Suggest customer
contact local
electric power
utility co. or
qualified
electrician.

Check the
power source
voltage.

5-15

CONDITION

CONDITION CHECK RESULT CAUSE REMEDY

No microwave
oscillation.

No continuity.

Continuity.

Abnormal

Defective high
voltage
transformer.

Replace high
voltage
transformer.

Normal

Defective PCB
assembly.

Replace PCB
assembly.

Disconnect the
wire leads from

and check

continuity of relay 3

Check high vol­tage transformer

Output is full power
when you set lower
power level.

Abnormal.

Defective PCB
assembly.

Replace PCB
assembly.

Disconnect the
wire leads from
relay 3 and check
continuity relay 3
(Operate the unit)

Abnormal

Defective high
voltage capacitor.

Replace high
voltage capacitor.

Normal

Check high vol­tage capacitor.

Abnormal

Defective high
voltage diode.

Replace high
voltage diode.

Normal

Check high vol­tage diode.

Abnormal

Defective
magnetron.

Replace
magnetron.

Check
magnetron.

(TROUBLE 5)

No microwave oscillation even though oven lamp and blower motor run.

(Display operates properly)

NOTE : • Make sure the wire leads correct position.

• When Removing the wire leads from the parts, be sure to grasp the connector, not the wires.

• When removing the magnetron, be sure to install the magnetron gasket in the correct position
and in good condition.

relay 3

, not the wires., not the wires.

(Operate the unit)

, not the wires.

DOOR PARTS

CONTROL PANEL PARTS

LATCH BOARD PARTS

BASE PLATE PARTS

OVEN CAVITY PARTS

INTERIOR PARTS

INTRODUCTION

MODEL : RS511MB

RFS511G
URS511MB

EXPLODED VIEW

6-1

DOOR PARTS

CONTROL PANEL PARTS

LATCH BOARD PARTS

BASE PLATE PARTS

INTERIOR PARTS

OVEN CAVITY PARTS

#EV#

EXPLODED VIEW

INTRODUCTION

MODEL : RCS511A

RS511P
RFS511SW2A
URS511P
URCS511A

6-2

#EV#

DOOR PARTS

MODEL : RS511MB

RFS511G
URS511MB
RCS511A
RS511P
RFS511SW2A
URS511P
URCS511A

1013

1005

1004

1385

1002

1000

W136

1006

1007

W105

W108

1384

1009

W206

W207

1386

6-3

2012

2400

2005

2006

2381

2000

W130

W102

#EV#

CONTROL PANEL PARTS

MODEL : RFS511G

6-4

2012

2400

2005

2006

2381

W130

2000

2002

W102

#EV#

CONTROL PANEL PARTS

MODEL : RS511MB

URS511MB

6-5

2004

2381

2000

2002

2006

W130

W102

#EV#

CONTROL PANEL PARTS

MODEL : RS511P

URS511P

6-6

2004

2006

2381

2000

W130

W102

#EV#

CONTROL PANEL PARTS

MODEL : RCS511A

RFS511SW2A
URCS511A

6-7

7037

9000

3001

5045

W121

W109

W158

W121

W109

3009

W105

W109

3004

5024

W109

W108

#EV#

OVEN CAVITY PARTS

MODEL : RS511MB

RFS511G
URS511MB
RCS511A
RS511P
RFS511SW2A
URS511P
URCS511A

6-8

#EV#

LATCH BOARD PARTS

MODEL : RS511MB

RFS511G
URS511MB
RCS511A
RS511P
RFS511SW2A
URS511P
URCS511A

4001

4000

4003

W102

W117

4009

W160

4008

4002

4004

6-9

6-10

5016

W109

5102

3031

W101

W136

5014

W109

W108

W101

W108

W130

W101

5202

5041

5103

5059

5201

5010

W101

W108

W109

5104

W109

5001

5051

5302

W109

5019

5061

9000

3381

3028

W101

5008

5020

5067

5009

W104

W101

3006

4810WRC002A

0CZZW1H009A

5000

After

Before

6021W3B001L

6851W1A001G

5013

3007

5203

3383

Discord original for parts supplied.
Change pieces simultaneously.

INTERIOR PARTS

MODEL : RS511MB

RFS511G
URS511MB
RCS511A
RS511P
RFS511SW2A
URS511P
URCS511A

#EV#

6001

6000

W121

W108

6013

W121

3026

3901

3902

W162

#EV#

BASE PLATE PARTS

MODEL : RS511MB

RFS511G
URS511MB
RCS511A
RS511P
RFS511SW2A
URS511P
URCS511A

6-11

SCHEMATIC DIAGRAM OF P.C.B

7-1

PRINTED CIRCUIT BOARD

7-2