R-770B
SERVICE MANUAL
S3811R770BPHR
DOUBLE GRILL
MICROWAVE OVEN
TURNOVER ADD STAND COVER
STIR DEFROST HELP
%
KG PCS AUTO
COOK
AUTO COOK
PIZZA
AUTO GRILL
1
2
3
4
5
CRISPY SNACK
Grilled Chicken
Potato Skin
Grilled Lobster
Garlic Bread
Chicken
Wings
Salty Peanuts
Grilled Fish
Steak
Fish Cake
RICE COOK
Convenient Food
REHEAT
STEAM MENU
MODEL
R-770B
HELP
SLOW COOK
POWER LEVEL
EASY DEFROST
GRILL
GRILL MIX
DOUBLE GRILL
1
6
2
7
3
8
4
9
5
O
STOP/CLEAR
INSTANT COOK/START
In interests of user-safety the oven should be restored to its original
condition and only parts identical to those specified should be used.
TABLE OF CONTENTS
Page
CAUTION, MICROWAVE RADIATION.................................................................................................... 1
WARNING .................................................................................................................................................1
PRODUCT SPECIFICATIONS ................................................................................................................ 2
GENERAL INFORMATION....................................................................................................................... 2
APPEARANCE VIEW .............................................................................................................................. 3
OPERATION SEQUENCE....................................................................................................................... 4
FUNCTION OF IMPORTANT COMPONENTS ....................................................................................... 7
SERVICING .............................................................................................................................................. 8
TROUBLESHOOTING GUIDE ................................................................................................................. 9
TEST PROCEDURE .............................................................................................................................. 10
TOUCH CONTROL PANEL ASSEMBLY .............................................................................................. 16
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE .................................................. 21
MICROWAVE MEASUREMENT ........................................................................................................... 26
WIRING DIAGRAM ................................................................................................................................ 27
PICTORIAL DIAGRAM .......................................................................................................................... 30
POWER UNIT CIRCUIT ......................................................................................................................... 31
CONTROL PANEL CIRCUIT .................................................................................................................. 32
PRINTED WIRING BOARD .................................................................................................................... 33
PARTS LIST .......................................................................................................................................... 34
SHARP CORPORATION
R-770B
R-770B
SERVICE MANUAL
PRODUCT SPECIFICATIONS
GENERAL INFORMATION
MICROWAVE OVEN WITH TOP
AND BOTTOM HEATER
APPEARANCE VIEW
R-770B
GENERAL IMPORTANT INFORMATION
OPERATING SEQUENCE
This Manual has been prepared to provide Sharp Corp. Service
engineers with Operation and Service Information.
It is recommended that service engineers carefully study the entire
text of this manual, so they will be qualified to render satisfactory
customer service.
FUNCTION OF IMPORTANT
COMPONENTS
CAUTION
MICROWAVE RADIATION
SERVICING AND
TROUBLESHOOTING GUIDE
Service engineers should not be exposed to the microwave
energy which may radiate from the magnetron or other microwave generating devices if it is improperly used or connected.
All input and output microwave connections, waveguides, flanges
and gaskets must be secured. Never operate the device without
a microwave energy absorbing load attached. Never look into
an open waveguide or antenna while the device is energized.
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 engineers.
TEST PROCEDURE
TOUCH CONTROL PANEL
COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE
MICROWAVE MEASUREMENT
WIRING DIAGRAM
All the parts marked "*" on parts list are used at voltages more than
250V.
Removal of the outer wrap gives access to potentials above 250V.
All the parts marked "∆" on parts list may cause undue microwave
exposure, by themselves, or when they are damaged, loosened or
removed.
Never operate the Top and/ or Bottom heater with the oven
outer cabinet removed. (Because air flow is eliminated, and the
excess heat generated on adjacent components). It can cause
permanent damage or a fire.
SHARP CORPORATION
OSAKA, JAPAN
1
PARTS LIST
R-770B
PRODUCT DESCRIPTION
SPECIFICATION
ITEM
DESCRIPTION
Power Requirements
Power Consumption
Power Output
Grill heater Power Output (Top heater)
Bottom heater Power Output
Case Dimensions
Cooking Cavity Dimensions
Turntable diameter
Control Complement
220 Volts
50 Hertz
Single phase, 3 wire earthed
Microwave cooking 1.6 kW
Top Heater mode
1.3 kW
Grill cooking
Bottom heater mode
0.9 kW
Top and Bottom heater mode
2.1 kW
900 W nominal of RF microwave energy (measured by method of IEC 705)
Operating frequency 2450 MHz
1200 W (600 W x 2)
800 W
Width
520 mm
Height 309 mm including foot
Depth
467 mm
Width
352 mm
Height 207 mm
Depth
368 mm
325 mm
Touch Control System
Clock (1:00 - 12:59) / Timer (0 - 90 minutes)
Microwave Power for Variable Cooking
Repetition Rate;
100% ................................................... Full power throughout the cooking time
70% ..................................................................... approx. 70% of FULL Power
50% ..................................................................... approx. 50% of FULL Power
30% ..................................................................... approx. 30% of FULL Power
10% ..................................................................... approx. 10% of FULL Power
Mix cooking
Grill Mix High with Top Heater ............ Top heater with 50% microwave power
Grill Mix Low with Top Heater ............. Top heater with 10% microwave power
Grill Mix High with Bottom Heater ....... Bottom heater with 50% microwave power
Grill Mix Low with Bottom Heater ........ Bottom heater with 10% microwave power
Set Weight
AUTO COOK pad, AUTO GRILL pad, PIZZA pad
CRISPY SNACK pad, RICE COOK pad, REHEAT pad
STEAM MENU pad, LESS (")/MORE (') pads
HELP pad, SLOW COOK pad, POWER LEVEL pad
EASY DEFROST pad, GRILL pad, GRILL MIX pad
Number pads, STOP/CLEAR pad, CLOCK pad
INSTANT COOK/START pad
Approx. 19 kg
GENERAL INFORMATION
WARNING
THIS APPLIANCE MUST BE EARTHED
IMPORTANT
THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:
GREEN-AND-YELLOW
BLUE
BROWN
: EARTH
: NEUTRAL
: LIVE
2
R-770B
APPEARANCE VIEW
OVEN
1. Oven lamp
2. Top heaters (Grill heaters)
3. See through door
4. Door hinges
5. Door safety latches
6. Door seals and sealing surfaces
7. Bottom heater
8. Oven cavity
9. Turntable motor shaft
10.Ventilation openings
11.Waveguide cover
12.Door opening button
Turntable
13.Control panel
support
14.Digital display
15.Power supply cord
16.Outer cabinet
Bottom
heater
4
1 2
t
0
r
0
q
5
e
8 9
y
3
6
0
High rack
7
0
w
NOTE:
1. Ensure that the bottom heater is in the lowest
position as shown the figure, as it is possible
to move it up and down to help with cleaning.
2. Place the turntable support over the turntable motor shaft on the floor of the cavity.
Low rack
3. Then place the turntable on to the turntable
support.
Turntable
Turntable
motor shaft
TOUCH CONTROL PANEL
1. TOP HEATER SYMBOL
The symbol will light when the top heater is in use.
2. BOTTOM HEATER SYMBOL
The symbol will light when the bottom heater is in use.
3. MICROWAVE SYMBOL
The symbol will light during microwave cooking.
A. AUTO COOK PAD
Press to select 4 popular menus.
B. AUTO GRILL PAD
Press to select 5 popular grill menus.
C. PIZZA PAD
Press to select 3 pizza menus.
D. CRISPY SNACK PAD
Press to select 5 popular snack menus.
E. RICE COOK PAD
Press to cook rice, congee or porridge.
F. REHEAT PAD
Press to reheat dish, soup, beverage or bread.
G. STEAM MENU PAD
Press to steam fish, meat or dumpling.
H. LESS (")/MORE (') pads
Press to adjust the doneness of food in one minute increments
during cooking or to increase/ decrease the time whilst programming the automatic operations.
I. HELP PAD
Press to select auto start, child lock, language or demonstration modes. Press to get cooking information.
J. SLOW COOK PAD
Press to cook slowly and longer time.
K. POWER LEVEL PAD
Press to select microwave power setting. If not pressed, HIGH
power is automatically selected.
L. EASY DEFROST PAD
Press to defrost meat by entering weight.
M. GRILL pad
Press to select GRILL mode.
N. GRILL MIX PAD
Press to select grill and microwave mix cooking mode.
O. NUMBER PADS
Press to enter cooking times, clock time, weight or quantity of
food.
3
TURNOVER ADD STAND COVER STIR DEFROST HELP
Indicator
1
2
3
%
KG PCS AUTO
A
B
CRISPY SNACK
AUTO GRILL
Grilled Chicken
Potato Skin
Grilled Lobster
Steak
Garlic Bread
Chicken
Wings
Salty Peanuts
Fish Cake
Convenient Food
Grilled Fish
REHEAT
RICE COOK
C
D
PIZZA
AUTO COOK
1
2
3
4
5
E
H
COOK
STEAM MENU
HELP
J
K
M
O
P
SLOW COOK
POWER LEVEL
GRILL
1
6
2
7
STOP/CLEAR
EASY DEFROST
GRILL MIX
3
8
4
9
5
O
INSTANT COOK/START
F
G
I
L
N
Q
R
P. STOP/CLEAR PAD
Press to clear during programming. Press
once to stop operation of oven during cooking;
Press twice to cancel cooking programme.
Q. CLOCK PAD
Press to set clock time.
R. INSTANT COOK/START PAD
Press once to cook for 1 minute at 100%
(HIGH power) or increase by 1 minute multiples each time this pad is pressed during
cooking. Press to start oven after setting programs.
R-770B
OPERATION SEQUENCE
OFF CONDITION
Closing the door activates the 1st. latch switch, 2nd.
interlock relay control switch.
IMPORTANT:
When the oven door is closed, the contacts COM-NC
of the monitor switch must be open. When the microwave oven is plugged in a wall outlet (220V 50Hz), the
line voltage is supplied to the noise filter and the
control unit.
Switch
Contact
1st. latch switch
2nd. interlock relay
control switch
Monitor Switch
COM-NO
Condition
During
Oven Door
Cooking Open(No cooking)
Closed
Opened
COM-NO
Closed
Opened
COM-NC
Opened
Closed
MICROWAVE COOKING CONDITION
The circuit to the high voltage transformer, fan motor and
turntable motor are cut off when the 1st. latch switch, 2nd.
interlock relay control switch are made open. The oven
lamp remains on even if the oven door is opened after the
cooking cycle has been interrupted, because the relay
RY6 stay closed. Shown in the display is remaining time.
6. MONITOR SWITCH CIRCUIT
The monitor switch is mechanically controlled by the
oven door, and monitors the operation of the 1st. latch
switch and the nd. interlock relay RY2.
6-1. When the oven door is opened during or after the
cycle of a cooking program, the 1st. latch switch and
2nd. interlock relay control switch must open their
contacts first. After that the contacts (COM-NC) of the
monitor switch can be closed.
6-2. When the oven door is closed, the contacts (COMNC) of the monitor switch must be opened. After that
the contacts of the 1st. latch switch and the 2nd.
interlock relay control switch are closed.
6-3. When the oven door is opened and the contacts of the
1st. latch switch and 2nd. interlock relay remain
closed, the fuse M10A will blow, because the monitor
switch is closed and a short circuit is caused.
100% (HIGH) COOKING
Enter a desired cooking time by pressing the number pads
and start the oven by pressing START pad.
70% (MEDIUM HIGH), 50% (MEDIUM), 30% (MEDIUM LOW), 10% (LOW COOKING)
Figure O-1 on page 27
1. The oven display will show " SHARP MICRO- WAVE
OVEN " .
2. Press the STOP/CLEAR pad. The oven display will
show " :
".
3. Set the clock as follows.
3-1. Press the CLOCK pad once.
3-2. Enter the time of day by perssing the number
pads.
3-3. Start the clock by pressing the CLOCK pad.
NOTE:
1. If you do not set the clock, " : " will appear on the
display. When the operation of the oven is finished, " :
" will appear on the display instead of the time of day.
2. The oven can be also used when the clock is not set.
3. When the oven door is opened, the oven lamp comes
on at this time.
When the microwave oven is preset for variable cooking
power, the line voltage is supplied to the high voltage
transformer intermittently within a 32-second time base
through the relay contact which is coupled with the current-limiting relay RY2. The following levels of microwave
power are given.
Function sequence Figure O-2 on page 27
CONNECTED COMPONENTS
High voltage transformer
Grill heater (Top)
Bottom heater
Fan motor,
Oven lamp, Turntable motor
RELAY
RY2
RY3
RY4
RY5
RY6
32 sec. ON
SETTING
1. The line voltage is supplied to the primary winding of
the high voltage transformer. The voltage is converted
to about 3.3 volts A.C. output on the filament winding
and high voltage of approximately 2000 volts A.C. on
the secondary winding.
2. The filament winding voltage (3.3 volts) heats the
magnetron filament and the high voltage (2000 volts) is
sent to the voltage doubling circuit, where it is doubled
to negative voltage of approximately 4000 volts D.C..
3. The 2450 MHz microwave energy produced in the
magnetron generates a wave length of 12.24 cm. This
energy is channelled through the waveguide (transport
channel) into the oven cavity, where the food is placed
to be cooked.
4. When the cooking time is up, a signal tone is heard and
the relays RY2 + RY5 + RY6 go back to their home
position. The circuits to the oven lamp, high voltage
transformer, fan motor and turntable motor are cut off.
5. When the oven door is opened during a cooking cycle,
the switches come to the following condition.
Approx. 100%
100%
24 sec. ON
8 sec. OFF
18 sec. ON
14 sec. OFF
12 sec. ON
20 sec. OFF
6 sec. ON
26 sec. OFF
Approx. 70%
70%
Approx. 50%
50%
Approx. 30%
30%
10%
Note:
Approx. 10%
The On/Off time ratio does not exactly correspond
to the percentage of microwave power, because
approx. 2 seconds are needed for heating up the
magnetron filament.
GRILL COOKING CONDITIONS
The oven has three grill cooking condition. They are the
TOPHEATER mode, BOTTOM HEATER mode and TOP
AND BOTTOM HEATER mode.
4
R-770B
TOP HEATER MODE
GRILL MIX COOKING CONDITION
In this mode, the food is cooked by the top heaters. Press
the GRILL pad once and then enter the cooking time by
pressing the number pads. When the START pad is
pressed, the following operations occur:
The oven will cook food by supplying grill heaters (top
heaters or Bottom heater) and microwave energy alternately within a 48 seconds time base. And the oven has
four programmed cooking mode.
Figure O-3(a) on page 27
The relay RY3 + RY5 + RY6 are energized.
The numbers of the digital read-out start the count
down to zero.
Then the top heaters, turntable motor, oven lamp and
fan motor are energized.
Now, the food is grilled by the top heaters.
Upon completion of the selected cooking time, audible
signal sounds and the contacts of relays RY3 + RY6
are opened, then the top heaters, turntable motor and
oven lamp are de-energized. But the relay RY5 stays
closed and the fan motor operates for 5 minutes. But if
the cooking time is less than 2 minutes the relay RY5
will not stay close.
GRILL MIX HIGH WITH TOP HEATER MODE AND
GRILL MIX LOW WITH TOP HEATER MODE
1.
2.
3.
4.
5.
In these modes, the food is cooked by the top heaters and
the microwave energy. Press the GRILL MIX pad once for
GRILL MIX HIGH with TOP HEATER mode. Press the
GRILL MIX pad twice for GRILL MIX LOW with TOP
HEATER mode. And then enter the cooking time by
pressing the number pads. When the START pad is
pressed, the following operations occur:
Figure O-4(a) on page 29
1. The relay RY5 + RY6 are energized.
2. The numbers of the digital read-out start the count
down to zero.
3. The turntable motor, oven lamp and fan motor are
energized.
4. The relay RY2 + RY3 are energized alternately within
a 48 seconds time base by the control unit.
5. The top heaters operate through the relay RY3 is
energized. And the high voltage transformer operates
through the relay RY2 is energized.
6. The relationship between the top heating elements and
magnetron operations are as follows.
BOTTOM HEATER MODE
In this mode, the food is cooked by the bottom heater.
Press the GRILL pad twice and then enter the cooking time
by pressing the number pads. When the START pad is
pressed, the following operations occur:
Figure O-3(b) on page 28
1. The relay RY4 + RY5 + RY6 are energized.
2. The numbers of the digital read-out start the count
down to zero.
3. Then the bottom heater, turntable motor, oven lamp
and fan motor are energized.
4. Now, the food is grilled by the bottom heater.
5. Upon completion of the selected cooking time, audible
signal sounds and the contacts of relays RY4 + RY6
are opened, then the bottom heating elements, turntable motor and oven lamp are de-energized. But the
relay RY5 stays closed and the fan motor operates for
5 minutes. But if the cooking time is less than 2 minutes
the relay RY5 will not stay close.
26 SEC.
22 SEC.
ON
(MICRO.)
OFF
MICROWAVE POWER
= APPROX. 50%
ON
TOP
HEATERS
OFF
GRILL MIX HIGH with TOP HEATER mode
8 SEC.
40 SEC.
ON
(MICRO.)
OFF
MICROWAVE POWER
= APPROX. 10%
TOP AND BOTTOM HEATER MODE
ON
In this mode, the food is cooked by both the top heaters
and bottom heater. Press the GRILL pad three times and
then enter the cooking time by pressing the number pads.
When the START pad is pressed, the following operations
occur:
TOP
HEATERS
OFF
GRILL MIX LOW with TOP HEATER mode
Note:
The On/Off time ratio does not exactly correspond
to the percentage of microwave power, because
approx. 2 seconds are needed for heating up the
magnetron filament.
7. Upon completion of the selected cooking time, audible
signal sounds and the contacts of relays RY2 + RY3 +
RY6 are opened, then the top heaters, high voltage
transformer, turntable motor and oven lamp are deenergized. But the relay RY5 stays closed and the fan
motor operates for 5 minutes. But if the cooking time is
less than 2 minutes the relay RY5 will not stay close.
Figure O-3(c) on page 28
1. The relay RY3 + RY4 + RY5 + RY6 are energized.
2. The numbers of the digital read-out start the count
down to zero.
3. Then the top heaters, bottom heater, turntable motor,
oven lamp and fan motor are energized.
4. Now, the food is grilled by the top heaters and the
bottom heater.
5. Upon completion of the selected cooking time, audible
signal sounds and the contacts of relays RY3 + RY4 +
RY6 are opened, then the top heating elements, bottom heating element, turntable motor and oven lamp
are de-energized. But the relay RY5 stays closed and
the fan motor operates for 5 minutes. But if the cooking
time is less than 2 minutes the relay RY5 will not stay
closed.
GRILL MIX HIGH WITH BOTTOM HEATER MODE AND
GRILL MIX LOW WITH BOTTOM HEATER MODE
IIn these modes, the food is cooked by the bottom heater
and the microwave energy. Press the GRILL MIX pad
three (3) times for GRILL MIX HIGH with BOTTOM
HEATER mode. Press the GRILL MIX pad four (4) times
for GRILL MIXLOW with BOTTOM HEATER mode. And
then enter the cooking time by pressing the number pads.
5
R-770B
When the START pad is pressed, the following operations
occur:
Figure O-4(b) on page 29
1. The relay RY5 + RY6 are energized.
2. The numbers of the digital read-out start the count
down to zero.
3. The turntable motor, oven lamp and fan motor are
energized.
4. The relay RY2 + RY4 are energized alternately within
a 48 seconds time base by the control unit.
5. The bottom heater operate through the relay RY4 is
energized. And the high voltage transformer operates
through the relay RY2 is energized.
6. The relationship between the top heating elements and
magnetron operations are as follows.
26 SEC.
protect the oven door against temperature rising.
Cooking mode
22 SEC.
OFF
MICROWAVE POWER
= APPROX. 50%
ON
BOTTOM
HEATER
OFF
GRILL MIX HIGH with BOTTOM HEATER mode
8 SEC.
40 SEC.
ON
(MICRO.)
OFF
MICROWAVE POWER
= APPROX. 10%
ON
BOTTOM
HEATER
Time base
(seconds)
Microwave
100% Power
Top heaters
20
70
32
30
50
48
Bottom heater
Top browner and
Bottom browner
or Oven cooking
15
50
48
10 (Top)
10 (Bottom)
50
50
48
48
NOTE:
1. In case of Automatic operations, the limitations of
power output are not carried out.
2. In case that the STOP/CLEAR pad is pressed or the
oven door is opened during cooking, the limitations of
power output are carried out after the total cooking time
beyond the specified cooking time.
3. In case of the two or more same cooking modes are
carried out, the limitations of power output are carried
out after the total cooking time beyond the specified
cooking time.
4. In case of the two or more different cooking modes are
carried out, the specified cooking time is started to
count from the point when the cooking mode is changed.
5. If the cooking mode has the power level display, the
power level is also displayed when the limitations of
power output are carried out.
ON
(MICRO.)
Specified cooking Limited power
time (minutes)
output (%)
OFF
GRILL MIX LOW with BOTTOM HEATER mode
Note:
The On/Off time ratio does not exactly correspond
to the percentage of microwave power, because
approx. 2 seconds are needed for heating up the
magnetron filament.
7. Upon completion of the selected cooking time, audible
signal sounds and the contacts of relays RY2 + RY4 +
RY6 are opened, then the bottom heater, high voltage
transformer, turntable motor and oven lamp are deenergized. But the relay RY5 stays closed and the fan
motor operates for 5 minutes. But if the cooking time is
less than 2 minutes the relay RY5 will not stay close.
AUTOMATIC OPERATIONS
This oven has the following automatic operations;
PIZZA
CRISPY SNACK
AUTO COOK
AUTO GRILL
REHEAT
STEAM MENU
RICE COOK
EASY DEFROST
Thease will automatically compute the cooking mode and
the cooking time. And the oven will cook or defrost the food
according to the special cooking sequence.
LIMITATIONS OF POWER OUTPUT IN MANUAL
OPERATION
After the same cooking mode is carried out for more than
the specified cooking time, the power output is automatically reduced by turning the control relays on and off
intermittently, as shown in the table below. This is to
6
R-770B
FUNCTION OF IMPORTANT COMPONENTS
DOOR OPEN MECHANISM
HIGH VOLTAGE FUSE 0.75A
The door can be opened by pushing the open button on the
control panel. When the open button is pushed, the switch
lever is moved upward, operating the latch head. The latch
head is moved upward and released from the latch hook.
Now, the door can be opened.
The high voltage fuse blows when the high voltage rectifier
or the magnetron is shorted.
THERMAL CUT-OUT 125˚C (MG)
This thermal cut-out protects the magnetron against overheating. If the temperature goes up higher than 125˚C
because the fan motor is interrupted or the ventilation
openings are blocked, the thermal cut-out will open and
line voltages to the high voltage transformer will be cut off
and the operation of the magnetron will be stopped. The
thermal cut-out will cut back in at 95˚C.
Latch Heads
Latch Hook
2nd. Interlock
Relay Control
Switch
THERMAL CUT-OUT170˚C (OVEN)
Door
The thermal cut-out located on the top of the oven cavity
is designed to prevent damage to the oven if the foods in
the oven catch fire due to over heating produced by
improper setting of the cooking time or failure of control
unit. Under the normal operation, the oven thermal cut-out
remains closed. However, when abnormally high temperature are reached within the oven cavity, oven thermal
cut-out will open at 170˚C causing the oven to shut down.
The thermal cut-out will cut back in at 155˚C.
Monitor Switch
1st. Latch Switch
Switch Lever
Figure D-1. Door Open Mechanism
1ST. LATCH SWITCH AND 2ND. INTERLOCK
RELAY CONTROL SWITCH
TURNTABLE MOTOR
1. When the oven door is closed, the contacts (COM-NO)
of each switch must be closed.
2. When the oven door is opened, the contacts (COMNO) of each switch must be opened.
The turntable motor drives the turntable roller assembly to
rotate the turntable.
MONITOR SWITCH
The fan motor drives a blade which draws external cool air.
This cool air is directed through the air vanes surrounding
the magnetron and cools the magnetron. This air is channelled through the oven cavity to remove steam and
vapours given off from heating food. It is then exhausted
through the exhausting air vents of the oven cavity.
FAN MOTOR
1. When the door is closed, the contacts (COM-NC) must
be opened.
2. When the door is opened, the contacts (COM-NC)
must be closed.
3. If the oven door is opened and he contacts (COM-NO)
of the 1st. latch switch and 2nd. interlock relay RY2 fail
to open, the fuse M10A blows immediately after closing
the contacts (COM-NC) of the monitor switch.
NOISE FILTER
The noise filter assembly prevents radio frequency interference that might flow back in the power circuit.
CAUTION: BEFORE REPLACING A BLOWN FUSE
M10A TEST THE 1ST. LATCH SWITCH, 2ND.
INTERLOCK RELAY RY2, MONITOR
SWITCH AND MONITOR RESISTOR FOR
PROPER OPERATION. (REFER TO CHAPTER “TEST PROCEDURE”).
TOP HEATERS
The top heaters are located on the top of the oven cavity
assembly. The top heaters send out heat to grill foods.
BOTTOM HEATER
FUSE M10A 250V
The bottom heater is located on the floor of the oven cavity
assembly. Thebottom heater sends out heat to grill foods.
1. If the wire harness or electrical components are shortcircuited, this fuse blows to prevent an electric shock or
fire hazard.
2. This fuse blows when the 1st. latch switch and 2nd.
interlock relay RY2 remain closed with the oven door
open and when the contacts (COM-NC) of monitor
switch closes.
FUSE 15A
If the wire harness or electrical components are shortcircuited, this fuse blows to prevent an electric shock or fire
hazard.
7
R-770B
SERVICING
WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of producing very high voltage and current. Contact with following parts will
result in electrocution.
High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier assembly, High voltage harness.
REMEMBER TO CHECK 3D
REMEMBER TO CHECK 4R
1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge high voltage capacitor.
1) Reconnect all leads removed from components during testing.
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run the oven. Check all functions.
WARNING: AGAINST THE CHARGE OF THE
HIGH-VOLTAGE CAPACITOR.
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 level to HIGH (100%) and set the
microwave timer for two (2) minutes. And push the start
key. When the two minutes has elapsed (timer at zero)
carefully check that the water is now hot. If the water
remains cold carry out 3D checks and re-examine the
connections to the component being tested.
The high-voltage capacitor remains charged about
60 seconds after the oven has been switched off.
Wait for 60 seconds and then short-circuit the connection of the high-voltage capacitor (that is, of the
connecting lead of the high-voltage rectifier) against
the chassis with the use of an insulated screwdriver.
Sharp recommend that wherever possible fault-finding is
carried out with the supply disconnected. It may in, some
cases, be necessary to connect the supply after the outer
case has been removed, in this event carry out 3D
checks and then disconnect the leads to the primary of
the high voltage transformer. Ensure that these leads
remain isolated from other components and the oven
chassis. (Use insulation tape if necessary.) When the
testing is completed carry out 3D checks and reconnect
the leads to the primary of the high voltage transformer.
When all service work is completed, and the oven is fully assembled, the microwave power output should be checked
and microwave leakage test carried out.
TROUBLESHOOTING GUIDE
IMPORTANT: If the oven becomes inoperative because
of a blown fuse M10A in the 1st. latch
switch - 2nd. interlock relay(RY2)- monitor
switch - monitor resistor circuit, check the
1st. latch switch, 2nd. interlock relay(RY2),
monitor switch and monitor resistor before replacing the fuse M10A.
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.
8
R-770B
CONDITION
PROBLEM
Fuse 15A blows when power cord is
plugged into wall outlet.
Fuse M10A blows when the door is
opened.
Oven lamp does not light when door
is opened. (Display operates.)
OFF
CONDITION
Home fuse blows when power cord
is plugged into wall outlet.
"SHARP MICRO- OVEN PRESS
STOP" does not appear in display
when power cord is plugged into wall
outlet.
Display does not operate properly
when STOP/CLEAR pad is pressed.
Oven does not start when the INSTANT COOK/ START pad is
pressed. (Display operates.)
Oven lamp does not light. (Turntable motor operates.)
COOKING
CONDITION
(COMMON MODE)
Fan motor does not operate. (Oven
lamp lights.)
Turntable motor does not operate.
(Oven lamp lights.)
Oven or electrical parts does not stop
when cooking time is 0 or STOP/
CLEAR pad is pressed.
Oven goes into cook cycle but shuts
down before end of cooking cycle.
MICROWAVE
COOKING
CONDITION
GRILL
COOKING
CONDITION
GRILL MIX
COOKING
CONDITION
M N O O O O OP
MAGNETRON
HIGH VOLTAGE TRANSFORMER
H.V. RECTIFIER ASSEMBLY
HIGH VOLTAGE CAPACITOR
1ST. LATCH SWITCH
MONITOR SWITCH
2ND. INTERLOCK RELAY CONTROL SWITCH
THERMAL CUT-OUT 125˚C
THERMAL CUT-OUT 170˚C
FUSE M10A
FUSE 15A
NOISE FILTER
FAN MOTOR
TURNTABLE MOTOR
TOP HEATIER S
BOTTOM HEAER
HIGH VOLTAGE FUSE
POWER SUPPLY CORD
OVEN LAMP
SHORTED WIRE HARNESS
OPENED WIRE HARNESS
MIS-ADJUSTMENT OF SWITCHES
TOUCH CONTROL PANEL
KEY UNIT
RELAY RY2
RELAY RY3
RELAY RY4
RELAY RY5
RELAY RY6
FOIL PATTERN ON P.W.B.
POSSIBLE CAUSE
AND
DEFECTIVE PARTS
TEST PROCEDURE A B C D E E E F F G H I J J K K L
Oven seems to be operating but little or no heat is produced in oven
load.
Oven does not operating properly
during variable cooking condition
except 100% cooking condition.
Top heaters do not operate.
Bottom heater does not operate.
Oven seems to be operating but little or no heat is produced in oven
load. (Microwave power does not
seem to be generated properly.)
Top heaters do not operate.
Bottom heater does not operate.
9
R-770B
TEST PROCEDURES
PROCEDURE
LETTER
A
MAGNETRON TEST
COMPONENT TEST
NEVER TOUCH ANY PART IN THE CIRCUIT WITH YOUR HAND OR AN INSULATED TOOL
WHILE THE OVEN IS IN OPERATION.
CARRY OUT 3D CHECKS.
Isolate the magnetron from high voltage circuit by removing all leads connected to filament terminal.
To test for an open circuit filament use an ohmmeter to make a continuity test between the magnetron
filament terminals, the meter should show a reading of less than 1 ohm.
To test for short filament to anode condition, connect ohmmeter between one of the filament terminals
and the case of the magnetron (ground). This test should be indicated an infinite resistance. If a low
or zero resistance reading is obtained then the magnetron should be replaced.
MICROWAVE OUTPUT POWER (1 litre load)
The following test procedure should be carried out with the microwave oven in a fully assembled
condition (outer case fitted). Microwave output power from the magnetron can be measured by way
of IEC 705, i.e. it is measured by how much power the water load can absorb. To measure the
microwave output power in the microwave oven, the relation of calorie and watt is used. When P(W)
heating works for t(second), approximately P x t/4.187 calorie is generated. On the other hand, if the
temperature of the water with V(ml) rises ∆T (°C) during this microwave heating period, the calorie of
the water is V x ∆T.
The formula is as follows;
P x t / 4.187 = V x ∆ T
P (W) = 4.187 x V x ∆T / t
Our condition for water load is as follows:
Room temperature ........... around 20°C
Power supply Voltage .............. Rated voltage
Water load.................................. 1000 g
Initial temperature .............................. 10±2°C
Heating time .............................. 47 sec.
P = 90 x ∆T
Measuring condition:
1. Container
The water container must be a cylindrical borosilicate glass vessel having a maximum material
thickness of 3 mm and an outside diameter of approximately 190 mm.
2. Temperature of the oven and vessel
The oven and the empty vessel are at ambient temperature prior to the start the test.
3. Temperature of the water
The initial temperature of the water is (10±2)°C.
4. Select the initial and final water temperature so that the maximum difference between the final water
temperature and the ambient temperature is 5K.
5. Select stirring devices and measuring instruments in order to minimize addition or removal of heat.
6. The graduation of the thermometer must be scaled by 0.1°C at minimum and be an accurate
thermometer.
7. The water load must be (1000±5) g.
8. “t” is measured while the microwave generator is operating at full power. Magnetron filament heatup time is not included.
NOTE: The operation time of the microwave oven is “t + 2” sec. (2 sec. is magnetron filament heat-up time.)
Measuring method:
1. Measure the initial temperature of the water before the water is added to the vessel.
(Example: The initial temperature T1 = 11°C)
2. Add the 1 litre water to the vessel.
3. Place the load on the centre of the shelf.
4. Operate the microwave oven at HIGH for the temperature of the water rises by a value ∆ T of
(10 ± 2) K.
5. Stir the water to equalize temperature throughout the vessel.
6. Measure the final water temperature. (Example: The final temperature T2 = 21°C)
7. Calculate the microwave power output P in watts from above formula.
10
R-770B
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
Initial temperature .................................................................................................. T1 = 11°C
Temperature after (47 + 2) = 49 sec ...................................................................... T2 = 21°C
Temperature difference Cold-Warm ....................................................................... ∆T1 = 10C
Measured output power
The equation is “P = 90 x ∆T” ...................................................... P = 90 x 10°C = 900 Watts
JUDGMENT: The measured output power should be at least ± 15 % of the rated output power.
CAUTION: 1°C CORRESPONDS TO 90 WATTS. REPEAT MEASUREMENT IF THE POWER IS
INSUFFICIENT.
1000g
1000g
1000g
T1˚C
T2˚C
Heat up for 49 sec
B
HIGH VOLTAGE TRANSFORMER TEST
WARNING:
High voltage and large currents are present at the secondary winding and
filament winding of the high voltage transformer. It is very dangerous to work
near this part when the oven is on. NEVER make any voltage measurements
of the high-voltage circuits, including the magnetron filament.
CARRY OUT 3D CHECKS.
Disconnect the leads to the primary winding of the high voltage transformer. Disconnect the filament
and secondary winding connections from the rest of the HV circuitry. Using an ohmmeter, set on a low
range, it is possible to check the continuity of all three windings. The following readings should be
obtained:a. Primary winding ................................ approximately 1.5 Ω
b. Secondary winding .......................... approximately 117 Ω
c. Filament winding......................................... less than 1 Ω
If the readings obtained are not stated as above, then the high voltage transformer is probably faulty
and should be replaced.
CARRY OUT 4R CHECKS.
C
HIGH VOLTAGE RECTIFIER ASSEMBLY TEST
B
C
HIGH VOLTAGE RECTIFIER TEST
HIGH VOLTAGE RECTIFIER
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be tested
using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal B+C of the high
voltage rectifier and note the reading obtained. Reverse the meter leads and note this second reading.
The normal resistance is infinite in one direction and more than 100 kΩ in the other direction.
CARRY OUT 4R CHECKS.
NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF
THE MEASURING INSTRUMENT MUST HAVE A VOLTAGE AT LEAST 6 VOLTS, BECAUSE
OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIRECTIONS.
D
HIGH VOLTAGE CAPACITOR TEST
CARRY OUT 3D CHECKS.
A. Isolate the high voltage capacitor from the circuit.
B. Continuity check must be carried out with measuring instrument which is set to the highest
resistance range.
C. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩ after
it has been charged.
11
R-770B
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
D. A short-circuited capacitor shows continuity all the time.
E. An open capacitor constantly shows a resistance about 10 MΩ because of its internal 10MΩ
resistance.
F. When the internal wire is opened in the high voltage capacitor shows an infinite resistance.
G. The resistance across all the terminals and the chassis must be infinite when the capacitor is
normal.
If incorrect reading are obtained, the high voltage capacitor must be replaced.
CARRY OUT 4R CHECKS.
E
SWITCH TEST
CARRY OUT 3D CHECKS.
Isolate the switch to be tested and using an ohmmeter check between the terminals as described in
the following table.
Table: Terminal Connection of Switch
Plunger Operation
COM to NO
COM to NC
Released
Depressed
Open circuit
Short circuit
Short circuit
Open circuit
COM; Common terminal,
NO; Normally open terminal
NC; Normally close terminal
If incorrect readings are obtained, make the necessary switch adjustment or replace the switch.
CARRY OUT 4R CHECKS.
F
THERMAL CUT-OUT TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the thermal cut-out. Then using an ohmmeter, make a continuity
test across the two terminals as described in the below.
Table: Thermal Cut-out Test
Parts Name
Temperature of "ON"
condition (closed circuit).
(˚C)
Temperature of "OFF"
condition (open circuit).
(˚C)
Indication of ohmmeter
(When room temperature
is approx. 20˚C.)
Thermal cut-out 125˚C
This is not resetable type.
Above 125˚C
Closed circuit
Thermal cut-out 170˚C
Cuts back in at 155˚C.
Above 170˚C
Closed circuit
If incorrect readings are obtained, replace the thermal cut-out.
An open circuit thermal cut-out (MG) indicates that the magnetron has overheated, this may be due
to resistricted ventilation, cooling fan failure or a fault condition within the magnetron or HV. circuit.
An open circuit thermal cut-out (OVEN) indicates that the food in the oven cavity may catch fire, this
may be due to over heating produced by improper setting of the cooking timer or failure of the control
panel.
CARRY OUT 4R CHECKS.
G
BLOWN FUSE M10A
CARRY OUT 3D CHECKS.
If the fuse M10A is blown when the door is opened, check the 1st. latch switch, 2nd. interlock relay,
monitor switch and monitor resistor.
If the fuse M10A is blown, there could be a short or ground in electrical parts or wire harness. Check
them and replace the defective parts or repair the wire harness.
CARRY OUT 4R CHECKS.
CAUTION:
H
Only replace fuse M10A with the correct value replacement.
BLOWN FUSE 15A
CARRY OUT 3D CHECKS.
If the fuse 15A is blown, there could be a short or ground in electrical parts or wire harness. Check them
and replace the defective parts or repair the wire harness.
12
R-770B
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
CARRY OUT 4R CHECKS.
CAUTION:
I
Only replace fuse 15A with the correct value replacement.
NOISE FILTER TEST
N
WHT
L
RED
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of noise filter.
Using an ohmmeter, check between the terminals as
described in the following table.
MEASURING POINTS
Between N and L
Between terminal N and WHITE
Between terminal L and RED
F8A
INDICATION OF OHMMETER
Approx. 680 kΩ
Short circuit
Short circuit
If incorrect readings are absorbed, replace the noise filter unit.
CARRY OUT 4R CHECKS.
J
MOTOR WINDING TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two
terminals as described in the table below.
Table: Resistance of Motor
Motors
Resistance
Fan motor
Approximately 290 Ω
Turntable motor
Approximately 14 kΩ
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
K
TOP HEATERS AND BOTTOM HEATER TEST
CARRY OUT 3D CHECKS.
Before carrying out the following tests make sure the heater is cool completely.
1. Resistance of heater.
Disconnect the wire leads to the heater to be tested. Using ohmmeter with low resistance range.
Check the resistance across the terminals of the heater as described in the following table.
Table: Resistance of heater
Parts name
Resistance
Top heaters
Approximately 24 Ω x 2 = 48 Ω
Bottom heater
Approximately 72 Ω
2. Insulation resistance.
Disconnect the wire leads to the heater to be tested. Check the insulation resistance between the
heater terminal and cavity using a 500V - 100MΩ insulation tester. The insulation resistance should
be more than 10 MΩ in the cold start.
If the results of above test 1 and/or 2 are out of above specifications, the heater is probably faulty and
should be replaced.
CARRY OUT 4R CHECKS.
L
HIGH VOLTAGE FUSE TST
CARRY OUT 3D CHECKS.
If the high voltage fuse is blown, there could be a short in the high voltage rectifier or the magnetron.
Check them and replace the defective parts and the high voltage fuse.
CARRY OUT 4R CHECKS.
CAUTION:
Only replace high voltage fuse with the correct value replacement.
13
R-770B
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
M
CONTROL PANEL ASSEMBLY TEST
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore,
unlike conventional microwave ovens, proper maintenance can not be performed with only a voltmeter
and ohmmeter.
In this service manual, the touch control panel assembly is divided into two units, Control Unit and Key
Unit, and also the Control unit is divided into two units, CPU unit and Power unit, and troubleshooting
by replacement is described according to the symptoms indicated.
1. Key Unit Note : Check key unit ribbon connection before replacement.
The following symptoms indicate a defective key unit. Replace the key unit.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching a number pad, two figures or more are displayed.
c) When touching the pads, sometimes a pad produces no signal.
2. Control Panel
The following symptoms indicate a defective control unit. Before replacing the control unit.
perform the key unit test (Procedure N) to determine if control unit is faulty.
2-1 In connection with pads
a) When touching the pads, a certain group of pads do not produce a signal.
b) When touching the pads, no pads produce a signal.
2-2 In connection with indicators
a) At a certain digit, all or some segments do not light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light up.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
2-3 Other possible troubles caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Clock does not operate properly.
c) Cooking is not possible.
KEY UNIT TEST
G8
G7
G6
G5
G4
G3
G2
G1
G9
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon cable
is marking good contact, verify that the door sensing switch (stop switch) operates properly; that is the
contacts are closed when the door is closed and open when the door is open. If the door sensing switch
(stop switch) is good, disconnecct the flat ribbon cable that connects the key unit to the control unit and
make sure the door sensing switch is closed (either close the door or short the door sensing switch
connecter). Use the Key unit matrix indicated on the control panel schematic and place a jumper wire
between the pins that correspond to the STOP/CLEAR pad marking momentary contact. If the control
unit responds by clearing with a beep the key unit is faulty and must be replaced. If the control unit does
not respond, it is a faulty and must be replaced. If a specific pad does not respond, the above method
may be used (after clearing the control unit) to determine if the control unit or key pad is at fault.
5
4
3
2
1
CRISPY
SNACK
AUTO
COOK
PIZZA
G12 G11 G10
N
0
9
8
7
6
AUTO
GRILL
RICE
COOK
STOP/
CLEAR
INSTANT
COOK/ GRILL
MIX
START
POWER STEAM
LEVEL
MENU
EASY
DEFROST
CARRY OUT 4R CHECKS.
14
REHEAT
HELP
GRILL
SLOW
COOK
R-770B
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
O
RELAY TEST
COMPONENT TEST
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin Nos. 1 and 3 of the 4 pin connector (E) on the
control unit with an A.C. voltmeter.
The meter should indicate 220 volts, if not check oven circuit.
Relay Test
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation, grill
operation or grill mix operation.
DC. voltage indicated .......... Defective relay.
DC. voltage not indicated .... Check diode which is connected to the relay coil. If diode is good,
control unit is defective.
RELAY SYMBOL
OPERATIONAL VOLTAGE
CONNECTED COMPONENTS
RY2
RY3
Approx. 24.0V D.C.
Approx. 24.0V D.C.
High voltage transformer
Grill heaters (Top)
RY4
Approx. 24.0V D.C.
Bottom heater
RY5
Approx. 24.0V D.C.
Fan motor
RY6
Approx. 24.0V D.C.
Oven lamp / Turntable motor
CARRY OUT 4R CHECKS.
P
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
To protect the electronic circuits, this model is provided with a fine foil pattern added to the input circuit
on the PWB, this foil pattern acts as a fuse. If the foil pattern is open, follow the troubleshooting guide
given below for repair.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS.
STEPS
OCCURANCE
1
The rated AC voltage is not present at
Power terminal of CPU connector (CN-A).
CAUSE OR CORRECTION
Check supply voltage and oven power cord.
2
The rated AC voltage is present at primary
side of low voltage transformer.
Low voltage transformer or secondary circuit defective.
Check and repair.
3
Only pattern at "a" is broken.
*Insert jumper wire J1 and solder.
(CARRY OUT 3D CHECKS BEFORE REPAIR)
4
Pattern at "a" and "b" are broken.
*Insert the coil RCILF2003YAZZ between "c" and "d".
(CARRY OUT 3D CHECKS BEFORE REPAIR)
c
5
FAN
b
CARRY OUT 4R CHECKS.
VRS1
a
(J1)
NOTE: *At the time of these repairs, make a
visual inspection of the varistor for burning damage and examine the transformer
with tester for the presence of layer short
circuit (check primary coil resistance).
If any abnormal condition is detected,
replace the defective parts.
d
1
AC
CN - A
15
R-770B
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units as
shown in the touch control panel circuit.
3) Synchronizing Signal Circuit
The power source synchronizing signal is available in
order to compose a basic standard time in the clock
circuit. It accompanies a very small error because it
works on commercial frequency.
(1) Key Unit
(2) Control Unit (The Control unit consists of Power unit
and CPU unit.)
4) ACL
A circuit to generate a signals which resets the LSI to
the initial state when power is supplied.
The principal functions of these units and signals communicated among them are explained below.
Key Unit
The key unit is composed of a matrix, signals generated in
the LSI are sent to the key unit from P40, P41, P72, P73
P74, P75, P76 and P77.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through P44 - P47
to perform the function that was requested.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (key touch sound and completion
sound).
Control Unit
Control unit consists of LSI, power source circuit, synchronizing signal circuit, ACL circuit, buzzer circuit, relay
circuit, indicator circuit and back light circuit.
7) Relay Circuit
To drive the magnetron, grill heaters, bottom heater,
fan motor, turntable motor and light the oven lamp.
6) Door Sensing Switch (Stop Switch)
A switch to "tell" the LSI if the door is open or closed.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD1 - LD10).
1) LSI
This LSI controls the key strobe signal, relay driving
signal for oven function and indicator signal.
9) Indicator Circuit
This circuit consists of 7-digits, 39-segments and 3common electrodes using a Liquid Crystal Display.
2) Power Source Circuit
This circuit generates voltage necessary in the control
unit.
Symbol
VC
Voltage
-5.2V
Application
LSI(IC1)
16
R-770B
DESCRIPTION OF LSI
LSI(IZA859DR)
The I/O signal of the LSI(IZA859DR) are detailed in the following table.
Pin No.
Signal
I/O
1
C1
IN
Terminal not used.
2
VL1
IN
3-5
AN7-AN5
IN
Power source voltage input terminal.
Standard voltage for LCD.
Heating constant compensation terminal.
6-7
8
AN4-AN3
AN2
IN
IN
Terminal not used.
Input signal which communicates the door open/close information to LSI.
AN1-AN0
IN
Door closed; "H" level signal.
Door opened; "L" level signal.
Terminal not used.
P57
P56
IN
OUT
9-10
11
12
Description
Terminal not used.
Signal to sound buzzer.
A: key touch sound.
B: Completion sound.
0.12 sec
A
2.4 sec
B
13-18
P55-P50
IN/OUT
19
P47
IN
20
P46
IN
21
P45
IN
22
P44
IN
23
24
INT1
INT0
IN
IN
Terminal not used.
Signal coming from touch key.
When any one of G12 line keys on key matrix is touched, a corresponding signal
from P40, P41, P72, P73, P74, P75, P76 and P77 will be input into P47. When no
key is touched, the signal is held at "L" level.
Signal similar to P47.
When any one of G11 line keys on key matrix is touched, a corresponding signal
will be input into P46.
Signal similar to P47.
When any one of G10 line keys on key matrix is touched, a corresponding signal
will be input into P45.
Signal similar to P47.
When any one of G9 line keys on key matrix is touched, a corresponding signal will
be input into P44.
Terminal not used.
Signal to synchronized LSI with commercial power source
frequency(50Hz).
H : GND
This is basic timing for time processing of LSI.
L (-5V)
20 msec
25
P41
OUT
26
P40
OUT
27
P77
OUT
28
P76
OUT
29
P75
OUT
30
P74
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G8 line key on matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G7 line key on matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G6 line key on matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G5 line key on matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G4 line key on matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47
terminal while one of G3 line key on matrix is touched.
17
R-770B
Pin No.
31
Signal
P73
I/O
OUT
32
P72
OUT
33
P71
OUT
34
35
P70
RESET
IN
IN
36
P81
OUT
37
P80
OUT
38
XIN
IN
39
XOUT
OUT
40
VSS
IN
41
P27
OUT
42
43
P26
P25
IN/OUT
OUT
Description
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G2 line key on matrix is touched.
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P44 - P47 terminal
while one of G1 line key on matrix is touched.
Oven lamp and turntable motor driving signal(Square Waveform : 50Hz).
20 msec
To turn on and off shut-off relay (RY6). The
H
square waveform voltage is delivered to
the relay (RY6) driving circuit and relays
L
During cooking
(RY2,RY3,RY4,RY5) control circuit.
Connected to VC.
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied. Temporarily
set to "L" level the moment power is applied, at this time the LSI is reset. Thereafter
set at "H" level.
Magnetron high-voltage circuit driving signal.
To turn on and off the cook
ON/OFF time ratio in Mirelay (RY2). In 100% POWER
cro cooking
(a. 32second time base)
operation, the signals hold "L"
level during microwave
MICRO
ON
OFF
cooking and "H" level while not
COOK
cooking. In other cooking
100%
32sec.
0sec.
modes (70%, 50%, 30%, 10%)
70%
24sec.
8sec.
the signal turns to "H" level and 50%
18sec. 14sec.
"L" level in repetition
30%
12sec. 20sec.
according to the power level.
10%
6sec. 26sec.
Grill heaters (TOP HEATER) driving signal.
To turn on and off the grill heaters relay
(RY3). "L" level during grill (TOP GRILL,
TOP AND BOTTOM) cooking, or Grill Mix
(MICRO+TOP) cooking, "H" level
otherwise.
ON/OFF time ratio in Micro cooking
(a. 48second time base)
MICRO
COOK
100%
70%
50%
30%
10%
During
ON
cooking
(Grill or Grill Mix)
ON
OFF
48sec.
36sec.
26sec.
16sec.
8sec.
0sec.
12sec.
22sec.
32sec.
40sec.
OFF
H. GND
L
Internal clock oscillation frequency input setting.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit
with respect to XIN terminal.
Internal clock oscillation frequency control output.
Output to control oscillation input of XOUT.
Power source voltage: -5V.
VC voltage of power source circuit input.
Bottom heater driving signal.
To turn on and off the bottom relay (RY4).
"L" level during grill (BOTTOM HEATER,
TOP AND BOTTOM) cooking, or Grill
Mix(MICRO+BOTTOM) cooking. "H" level
otherwise.
Terminal not used.
Fan motor driving signal.
To turn on and off the fan motor relay
RY5. "L" level during cooking, or for 5
minutes after grill cooking or Grill Mix
cooking. "H" level otherwise.
44
45-48
P24
P23-P20
OUT
OUT
Terminal not used.
Segment data signal.
Connected to LCD. No connection in LCD.
49-50
P17-P16
OUT
Segment data signal.
Connected to LCD. No connection in LCD.
18
During
ON
cooking
(Grill or Grill Mix)
OFF
ON
OFF
H. GND
L
H. GND
L
During cooking, or for 5 minutes after
grill cooking or grill mix cooking
R-770B
Pin No.
Signal
I/O
SEG39-SEG10
OUT
Segment data signal.
Connected to LCD.
The relation between signals are as follows:
LSI signal (Pin No.) LCD (Pin No.) LSI signal (Pin No.) LCD (Pin No.)
SEG 0 (90) ............... SEG39 (51)
SEG20 (70) ............ SEG20 (20)
SEG 1 (89) ............... SEG38 (50)
SEG21 (69) ............ SEG19 (19)
SEG 2 (88) ............... SEG37 (49)
SEG22 (68) ............ SEG18 (18)
SEG 3 (87) ............... SEG36 (48)
SEG23 (67) ............ SEG17 (17)
SEG 4 (86) ............... SEG35 (47)
SEG24 (66) ............ SEG16 (16)
SEG 5 (85) ............... SEG34 (46)
SEG25 (65) ............ SEG15 (15)
SEG 6 (84) ............... SEG33 (45)
SEG26 (64) ............ SEG14 (14)
SEG 7 (83) ............... SEG32 (44)
SEG27 (63) ............ SEG13 (13)
SEG 8 (82) ............... SEG31 (43)
SEG28 (62) ............ SEG12 (12)
SEG 9 (81) ...................... NC (31)
SEG29 (61) ............ SEG11 (11)
SEG10 (80) .............. SEG30 (30)
SEG30 (60) ............ SEG10 (10)
SEG11 (79) .............. SEG29 (29)
SEG31 (59) .............. SEG 9 ( 9)
SEG12 (78) .............. SEG28 (28)
SEG32 (58) .............. SEG 8 ( 8)
SEG13 (77) .............. SEG27 (27)
SEG33 (57) .............. SEG 7 ( 7)
SEG14 (76) .............. SEG26 (26)
SEG34 (56) .............. SEG 6 ( 6)
SEG15 (75) .............. SEG25 (25)
SEG35 (55) .............. SEG 5 ( 5)
SEG16 (74) .............. SEG24 (24)
SEG36 (54) .............. SEG 4 ( 4)
SEG17 (73) .............. SEG23 (23)
SEG37 (53) .............. SEG 3 ( 3)
SEG18 (72) .............. SEG22 (22)
SEG38 (52) .............. SEG 2 ( 2)
SEG19 (71) .............. SEG21 (21)
SEG39 (51) .............. SEG 1 ( 1)
SEG9
OUT
SEG8-SEG0
OUT
Segment data signal.
Connected to LCD. No connection in LCD.
Segment data signal.
Connected to LCD. Signal is similar to SEG39.
91
VCC
IN
Connected to GND.
92
VREF
IN
Connected to GND.
93
AVSS
IN
Connected to VC.
94
COM3
OUT
95
COM2
OUT
96
COM1
OUT
97
COM0
OUT
VL3-VL2
IN
C2
IN
51-80
81
82-90
98-99
100
Description
Common data signal.
Connected to LCD (Pin No. 36). No connection in LCD.
Common data signal: COM3.
Connected to LCD (Pin No. 35).
Common data signal: COM2.
Connected to LCD (Pin No. 34).
Common data signal: COM1.
Connected to LCD (Pin No. 33).
Power source voltage input terminal.
Standard voltage for LCD.
Terminal not used.
19
R-770B
SERVICING
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the
circuits. When handling these parts, the following precautions should be strictly followed. CMOS LSI have
extremely high impedance at its input and output
terminals. For this reason, it is easily influenced by the
surrounding high voltage power source, static electricity charge in clothes, etc., and sometimes it is not fully
protected by the built-in protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly wrap
them in aluminium foil. Also wrap PW boards containing them in aluminium foil.
2) When soldering, ground the technician as shown in
the figure and use grounded soldering iron and
work table.
separated from each other. For those models,
therefore, it is possible to check and repair the
controls of the touch control panel while keeping
it apart from the oven proper; in this case you
must short both ends of the door sensing switch
(on PWB) of the touch control panel with a
jumper, which brings about an operational state
that is equivalent to the oven door being closed.
As for the sensor-related controls of the touch
control panel, checking them is possible if the
dummy resistor(s) with resistance equal to that
of the controls are used.
(2) Servicing the touch control panel with power
supply from an external power source:
Disconnect the touch control panel completely from
the oven proper, and short both ends of the door
sensing switch (on PWB) of the touch control panel,
which brings about an operational state that is
equivalent to the oven door being closed. Connect
an external power source to the power input terminal of the touch control panel, then it is possible to
check and repair the controls of the touch control
panel; it is also possible to check the sensor-related
controls of the touch control panel by using the
dummy resistor(s).
approx. 1M ohm
2. Shapes of Electronic Components
E
C
4. Servicing Tools
Tools required to service the touch control panel assembly.
1) Soldering iron: 30W
(It is recommended to use a soldering iron with a
grounding terminal.)
2) Oscilloscope: Single beam, frequency range: DC 10MHz type or more advanced model.
3) Others: Hand tools
B
Transistor
2SB1238
E
CB
Transistor
KRC243M
3. Servicing of Touch Control Panel
We describe the procedures to permit servicing of the
touch control panel of the microwave oven and the
precautions you must take when doing so.
To perform the servicing, power to the touch control
panel is available either from the power line of the oven
itself or from an external power source.
(1) Servicing the touch control panel with power
supply of the oven :
CAUTION:
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING
SERVICING AND PRESENTS A HAZARD .
Therefore, when checking the performance of the
touch control panel, put the outer cabinet on the
oven to avoid touching the high voltage transformer, or unplug the primary terminal (connector)
of the high voltage transformer to turn it off; the end
of such connector must be insulated with an insulating tape. After servicing, be sure to replace the
leads to their original locations.
A. On some models, the power supply cord between the touch control panel and the oven itself
is so short that the two can't be separated.
For those models, check and repair all the
controls (sensor-related ones included) of the
touch control panel while keeping it connected
to the oven.
B. On some models, the power supply cord between the touch control panel and the oven
proper is so long enough that they may be
5. Other Precautions
1) Before turning on the power source of the control
unit, remove the aluminium foil applied for preventing static electricity.
2) Connect the connector of the key unit to the control
unit being sure that the lead wires are not twisted.
3) After aluminium foil is removed, be careful that
abnormal voltage due to static electricity etc. is not
applied to the input or output terminals.
4) Attach connectors, electrolytic capacitors, etc. to
PWB, making sure that all connections are tight.
5) Be sure to use specified components where high
precision is required.
20
R-770B
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before
operating the oven.
1. Disconnect the oven from power supply.
2. Make sure that a definite” click” can be heard when the
microwave oven door is unlatched. (Hold the door in a
closed position with one hand, then push the door open
button with the other, this causes the latch leads to rise,
it is then possible to hear a “click’ as the door switches
operate.)
3. Visually check the door and cavity face plate for damage (dents, cracks, signs of arcing etc.).
1.
2.
3.
4.
5.
6.
Door does not close firmly.
Door hinge, support or latch hook is damaged.
The door gasket or seal or damaged.
The door is bent or warped.
There are defective parts in the door interlock system.
There are defective parts in the microwave generating
and transmission assembly.
7. There is visible damage to the oven.
Do not operate the oven:
1. Without the RF gasket (Magnetron).
2. If the wave guide or oven cavity are not intact.
3. If the door is not closed.
4. If the outer case (cabinet) is not fitted.
Carry out any remedial work that is necessary before
operating the oven.
Do not operate the oven if any of the following conditions
exist;
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any
of the following removal procedures:
WARNING FOR WIRING
heater, High voltage transformer and Oven cavity.
3) Sharp edge:
Bottom plate, Oven cavity, Waveguide flange,
Chassis support and other metallic plate.
4) Movable parts (to prevent a fault)
Fan blade, Fan motor, Switch, Switch lever,
Open button.
3. Do not catch the wire leads in the outer case cabinet.
4. Insert the positive lock connector certainly until its
pin is locked. And make sure that the wire leads
should not come off even if the wire leads is pulled.
5. To prevent an error function, connect the wire leads
correctly, referring to the Pictorial Diagram.
To prevent an electric shock, take the following
manners.
1. Before wiring,
1) Disconnect the power supply.
2) Open the door and wedge the door open.
3) Discharge the high voltage capacitor and wait for
60 seconds.
2. Don't let the wire leads touch to the following parts;
1) High voltage parts:
Magnetron, High voltage transformer, High voltage capacitor and High voltage rectifier assembly.
2) Hot parts:
Oven lamp, Magnetron, Grill heaters, Bottom
OUTER CASE REMOVAL
Ouer Case Cabinet
To remove the outer case proceed as follows.
1. Disconnect oven from power supply.
2. Open the oven door and wedge it open.
3. Remove the two (2) screws (LHSTIX screws) holding
the back plate to the oven cavity rear plate, by using
LHSTIX screw driver (LHSTIX "LR-4").
4. Remove the back plate.
5. Remove the five (5) screws from rear and along the
side edge of case.
6. Slide the entire case back about 3cm to free it from
retaining clips on the cavity face plate.
7. Lift the entire case from the oven.
8. Discharge the H.V. capacitor before carrying out any
further work.
9. Do not operate the oven with the outer case removed.
N.B.; Step 1, 2 and 8 form the basis of the 3D checks.
Back Plate
LHSTIX Screw
LHSTIX Screw Driver(Size LR-4)
CAUTION: DISCHARGE HIGH VOLTAGE CAPACITOR
BEFORE
TOUCHING
ANY
OVEN
COMPONENT OR WIRING.
21
R-770B
HIGH VOLTAGE COMPONENTS REMOVAL
(HIGH VOLTAGE CAPACITOR, HIGH VOLTAGE RECTIFIER ASSEMBLY AND HIGH VOLTAGE FUSE)
To remove the components, proceed as follows.
1. CARRY OUT 3D CHECKS.
2. Disconnect all the leads and terminals of high voltage
rectifier assembly from the high voltage capacitor.
3. Disconnect the high voltage fuse from the high voltage
transformer.
4. Now, the high voltage fuse is free.
5. Remove one (1) screw holding earth side terminal of
the high voltage rectifier assembly.
6. Remove one (1) screw holding capacitor holder to the
oven cavity rear plate.
7. Release the capacitor holder from the fan duct.
8. Remove the capacitor from the capacitor holder.
9. Now, the high voltage rectifier assembly and the capacitor should be free.
CAUTION: WHEN REPLACING HIGH VOLTAGE RECTIFIER ASSEMBLY, ENSURE THAT THE
CATHODE (EARTH) CONNECTION IS
SECURELY FIXED TO THE CAPACITOR
HOLDER AND BASE PLATE WITH AN
EARTHING SCREW.
HIGH VOLTAGE TRANSFORMER REMOVAL
1. CARRY OUT 3D CHECKS.
2. Disconnect the filament leads of high voltage transformer from high voltage capacitor and the magnetron.
3. Disconnect the high voltage fuse from the high voltage
transformer.
4. Disconnect the main wire harness from the high volt-
age transformer.
5. Remove the four (4) screws holding the transformer to
base plate.
6. Remove the transformer.
7. Now the high voltage transformer is free.
MAGNETRON REMOVAL
1. CARRY OUT 3D CHECKS.
2. Release the tabs of air intake duct from the chassis
support and the oven cavity.
3. Disconnect the high voltage wire of the high voltage
rectifier assembly and filament lead of the transformer
from the magnetron.
4. Remove the one (1) screw holding the chassis support
to the magnetron.
5. Move the air intake duct to left.
6. Carefully remove four (4) screws holding magnetron to
waveguide, when removing the screws hold the magnetron to prevent it from falling.
7. Remove the magnetron from the waveguide with care
so the magnetron antenna is not hit by any metal object
around the antenna.
CAUTION: WHEN REPLACING THE MAGNETRON,
BE SURE THE R.F. GASKET IS IN PLACE
AND THE MAGNETRON MOUNTING
SCREWS ARE TIGHTENED SECURELY.
POSITIVE LOCK® CONNECTOR (NO-CASE TYPE) REMOVAL
Terminal
1. CARRY OUT 3D CHECKS.
2. Push the lever of positive lock® connector.
3. Pull down on the positive lock ® connector.
Positive lock®
connector
4
CAUTION: WHEN CONNECTING THE POSITIVE LOCK®
CONNECTORS TO THE TERMINALS, INSTALL THE POSITIVE LOCK® SO THAT THE
LEVER FACES YOU
Push
Lever
5
Pull down
Figure C-1 Positive lock® connector
CONTROL PANEL ASSEMBLY REMOVAL
holding the CPU unit to the control panel frame.
9. Release the liquid crystal display (LCD) from the LCD
holder.
10.Now, the LCD sheet is free.
11.Release the two (2) tabs of the LCD holder holding the
CPU unit to the LCD holder.
12.Remove the LCD holder from the CPU unit.
13.Remove the two (2) screws holding the power unit to
the control panel frame.
14.Release the four (4) tabs of the control panel frame
holding the power unit to the control panel frame.
1 5. Now, the control unit (CPU unit + Power unit) is free.
NOTE: 1. Before attaching a new key unit, wipe off remaining adhesive on the control panel frame
CONTROL PANEL ASSEMBLY
1. CARRY OUT 3D CHECKS.
2. Disconnect the main wire harness and the switch harness from the power unit.
3. Straighten the tab of the oven cavity front flange
holding the tab of the control panel frame.
4. Lift up the control panel assembly.
5. Now, the control panel assembly is free.
CONTROL UNIT
6. Disconnect the flat ribbon cable from the connector CN-G.
7. Remove the two (2) screws holding the CPU unit to the
control panel frame.
8. Release the four (4) tabs of the control panel frame
22
R-770B
surfaces completely with a soft cloth soaked in
alcohol.
2. When attaching the key unit to the control panel
frame, adjust the upper edge and right edge of
the key unit to the correct position of control
panel frame.
3. Stick the key unit firmly to the control panel
frame by rubbing with soft cloth not to scratch.
FAN MOTOR REPLACEMENT
CAUTION:
• Once the fan blade has been removed, it
must be replaced with new one.
10.Remove the two (2) screws holding the fan motor to the
fan duct.
11.Now, the fan motor is free.
REMOVAL
1. CARRY OUT 3D CHECKS.
2. Remove the one (1) screw holding the noise filter to the
chassis support.
3. Release the noise filter from the tab on the fan duct.
4. Disconnect the wire leads from the fan motor.
5. Remove the one (1) screw holding the capacitor holder
to the oven cavity rear plate.
6. Remove the one (1) screw holding the fan duct to the
oven cavity rear plate.
7. Release the tabs of the capacitor holder from fan duct.
8. Remove the fan duct from the oven.
9. Remove the fan blade from the fan motor shaft according to the following procedure.
1) Hold the edge of the rotor of the fan motor by using
a pair of groove joint pliers.
CAUTION:
• Make sure that any pieces do not enter the gap
between the rotor and the stator of the fan
motor. Because the rotor is easy to be shaven
by pliers and metal pieces may be produced.
• Do not let the pliers touch the coil of the fan
motor because the coil may be cut or damaged.
• Do not distort the bracket by touching with the
pliers.
2) Remove the fan blade from the shaft of the fan
motor by pulling and rotating the fan blade with your
hand.
3) Now, the fan blade will be free.
INSTALLATION
1.
Install the fan motor to the fan duct with the two (2)
screws.
2. Fix the fan blade to the fan motor shaft according to
the following procedure.
1) Hold the centre of the bracket which supports the
shaft of the fan motor on a flat table.
2) Install the fan blade to the shaft of fan motor by
pushing the fan blade with a small, light weight, ball
peen hammer or rubber mallet.
3.
4.
5.
6.
Coil
7.
Groove joint pliers
CAUTION:
• Do not hit the fan blade when installing it
because the bracket may be deformed.
• Make sure that the fan blade rotates smoothly
after installation.
• Make sure that the axis of the shaft is not
slanted.
Install the fan duct to the oven cavity rear plate with the
one (1) screw.
Insert the tabs of the capacitor holder to the fan duct.
Install the capacitor holder to the oven cavity rear plate
with the one (1) screw.
Install the noise filter to the fan duct and the chassis
support with the one (1) screw.
Re-connect the wire leads to the fan motor.
Shaft
Shaft
Stator
Axis
Gap
Rotor
Bracket
Stator
These are the position
where should be pinched
with pliers
Rotor
Rear view
Table
Side view
Center of
bracket
TURNTABLE MOTOR REPLACEMENT
5. Now, the turntable motor is free.
6. After replacement use the one (1) screw provided with
the turntable motor assembly to fit turntable motor
cover.
1. Disconnect the oven from the power supply.
2. Remove the turntable motor cover by snipping of
material in four corners.
3. Where the corners have been snipped off, bend corner
areas flat. No sharp edge must be evident after removal of turntable motor cover.
4. Disconnect the wire leads from the turntable motor and
remove the two (2) screws holding the turntable motor.
NOTE: The one (1) screw to fit the turntable motor cover
should be XFPSD40P12K00, XFPSD40P10K00
or XFPSD40P08K000.
OVEN LAMP REMOVAL
1. CARRY OUT 3D CHECKS.
2. Remove the two (2) screws holding the air guide to
the top of the oven cavity.
3. Straighten the tab holding the lamp cover to the top of
the oven cavity.
4.
5.
6.
7.
23
Remove the lamp cover.
Disconnect the wire leads from the oven lamp.
Straighten the tab holding the oven lamp.
Remove the oven lamp from the top of the oven cavity.
R-770B
WARNING: Do not touch the oven lamp right after it is
turned off or during it is turned on. Be-
cause the oven lamp is halogen type and
it is very hot then.
POWER SUPPLY CORD REPLACEMENT
Removal
Re-install
1. CARRY OUT 3D CHECKS.
2. Remove the one (1) screw holding the green/yellow
wire to the cavity rear plate.
3. Disconnect the leads of the power supply cord from the
noise filter, referring to the Figure C-2(a).
4. Release the power supply cord from the oven cavity
rear plate.
5. Now, the power supply cord is free.
1. Insert the moulding cord stopper of power supply cord
into the square hole of the oven cavity rear plate,
referring to the Figure C-2(b).
2. Install the earth wire lead of power supply cord to the
cavity rear plate with one (1) screw and tight the screw.
3. Connect the brown and blue wire leads of power supply
cord to the noise filter correctly, referring to the Pictorial
Diagram.
Oven Cavity
Back Plate
Power Supply Cord
Screw
Brown Wire
Green/Yelow
Wire
Moulding
Cord Stopper
Power
Supply Cord
Bule Wire
L
N
WHT
RED
T1
Chassis
Support
Oven Cavity
Rear Plate
T2
Square Hole
Noise Filter
Figure C-2 (a) Replacement of Power Supply Cord
Figure C-2(b). Power Supply Cord Replacement
GRIL HEATERS (TOP HEATERS) REMOVAL
1. CARRY OUT 3D CHECKS.
2. Remove the one (1) screw holding the exhaust duct to
the oven cavity.
2. Remove the exhaust duct from the oven cavity.
4. Disconnect the wire leads from the grill heaters.
5. Lay down the two (2) tabs holding the reflector to the
oven cavity.
6. Remove the reflector from the oven cavity by sliding it
leftward.
7. Remove the grill heaters and the short terminal together from the oven cavity top plate.
8. Remove the two (2) screws holding the short terminal
to the grill heaters.
9. Now the individual grill heaters are free.
BOTTOM HEATER REMOVAL
1. CARRY OUT 3D CHECKS
2. Remove the fan duct from the oven cavity, referring to
"FAN MOTOR REPLACEMENT".
3. Disconnect the wire leads from the bottom heater.
4. Remove the two (2) nuts holding the bottom heater with
the bottom heater angle and the heat seal spring to the
oven cavity right wall.
5. Remove the two (2) nuts holding the bottom heater with
the bottom heater angle and the heat seal spring to the
oven cavity left wall.
6. Remove the bottom heater from the oven cavity .
1ST. LATCH SWITCH, 2ND. INTERLOCK RELAY CONTROL SWITCH, AND MONITOR SWITCH REMOVAL
Latch Hook
1. CARRY OUT 3D CHECKS.
2. Remove the control panel assembly referring to "CONTROL PANEL ASSEMBLY REMOVAL".
3. Disconnect the leads from all switches.
4. Remove the two (2) screws holding the latch hook to
the oven cavity.
5. Remove the latch hook.
6. Push the retaining tab slightly and remove the switch.
Tab
2nd. Interlock
Relay Control
Switch
Monitor Switch
Tab
1st. Latch Switch
Tab
Figure C-3. Switches
24
R-770B
1ST. LATCH SWITCH, 2ND. INTERLOCK RELAY CONTROL SWITCH, AND MONITOR SWITCH ADJUSTMENT
If the 1st. latch switch, 2nd. interlock relay control switch
and monitor switch do not operate properly due to a misadjustment, the following adjustment should be made.
1. CARRY OUT 3D CHECKS.
2. Loosen the two (2) screws holding the latch hook to the
oven cavity front flange.
3. With the door closed, adjust the latch hook by moving
it back and forward or up and down. In and out play of
the door allowed by the latch hook should be less than
0.5 mm. The horizontal position of the latch hook
should be placed where the monitor switch has activated with the door closed. The vertical position of the
latch hook should be placed where the 1st. latch switch
and 2nd. interlock relay control switch have activated
with the door closed.
4. Secure the screws with washers firmly.
5. Make sure of the 1st. latch switch, 2nd. interlock relay
control switch and monitor switch operation. If those
switches have not activated with the door closed, two
(2) screw holding latch hook to oven cavity front flange
and adjust the latch hook position.
latched position. First check latch hook position, pushing and pulling the door toward the oven face. The
results (play of the door) should be less than 0.5mm.
2. The contacts (COM-NO) of the 1st. latch switch and
2nd. interlock relay control switch interrupt the circuit
before the door can be opened.
3. The contacts (COM-NC) of the monitor switch close
when the door is opened.
4. Re-install outer case and check for microwave leakage
around the door with an approved microwave survey
meter. (Refer to Microwave Measurement Procedure.)
Latch Heads
Latch Hook
2nd. Interlock
Relay Control
Switch
Door
Monitor Switch
1st. Latch Switch
After adjustment, make sure of following:
Switch Lever
1. In and out play of door remains less than 0.5 mm when
Figure C-4 Latch Switches Adjustment
DOOR REPLACEMENT
15.Remove the glass stopper from the door frame.
16.Slide the front door glass leftwards and then slide
upwards to release the tabs holding it.
17.Now, the front door glass is free
REMOVAL
1. CARRY OUT 3D CHECKS.
2. Push the open button and open the door slightly.
3. Insert an putty knife (thickness of about 0.5mm) into the
gap between the choke cover and door frame as shown
in Figure C-5 to free engaging parts.
4. Try the principles of the lever and lift up the choke cover
by inserting a putty knife as shown in Figure C-5.
5. Release choke cover from door panel.
6. Now choke cover is free.
RE-INSTALL
1. Re-install the front door glass to the door frame as
follows.
1) Insert the lower edge of the front door glass into the six
(6) tabs of the door frame.
2) Slide the front door glass upwards and insert the upper
edge of the front door glass into the five (5) tabs of the
door frame.
3) Slide the front door glass rightwards and insert the right
edge of the front door glass into the two (2) tabs of the
door frame.
2. Re-install the glass stopper to the door frame as
follows.
1) Re-install the glass stopper to the door frame so that
the two (2) holes of the glass stopper meet the two (2)
pins of the door frame.
2) Hold the glass stopper to the door frame with the two
(2) screws.
3. Re-install the latch spring to the latch head. Re-install
the latch spring to the door frame. Re-install latch head
to door frame.
4. Re-install door panel to door frame by fitting seven (7)
tabs of door frame to seven (7) holes of door panel.
5. Hold the door panel to the door frame with four (4)
screws.
6. Catch two (2) pins of door panel on two (2) hole of upper
and lower oven hinges.
7. Re-install choke cover to door panel by pushing.
Note: After any service to the door;
(A) Make sure that door sensing switch and primary
latch switch are operating properly. (Refer to
chapter "Test Procedures".).
(B) An approved microwave survey meter should be
Choke Cover
Putty Knife
Door Frame
Figure C-5. Door Disassembly
7. Release two (2) pins of door panel from two (2) hole of
upper and lower oven hinges by lifting up.
8. Now, door sub assembly is free from oven cavity.
9. Remove the four (4) screws holding the door panel to
the door frame.
10.Release door panel froms seven (7) tabs of door frame
by sliding door panel downward.
11.Now, door panel is free.
12.Slide latch head upward and remove it from door frame
with releasing latch spring from door frame and latch
head.
13.Now, latch head and latch spring are free.
14.Remove the two (2) screws holding the glass stopper
to the door frame.
25
R-770B
used to assure compliance with proper microwave radiation emission limitation standards.
(Refer to Microwave Measurement Procedure.)
tight. Therefore, occasional appearance of moisture, light or sensing of gentle warm air movement
around oven door is not abnormal and do not in
themselves indicate a leakage of microwave energy from oven cavity.
After any service, make sure of the following :
1. Door latch heads smoothly catch latch hook through
latch holes and that latch head goes through centre of
latch hole.
2. Deviation of door alignment from horizontal line of
cavity face plate is to be less than 1.0mm.
3. Door is positioned with its face pressed toward cavity
face plate.
4. Check for microwave leakage around door with an
approved microwave survey meter. (Refer to Microwave Measurement Procedure.)
Note:
Pin
Upper
Oven
Hinge
Upper Oven
Hinge
Door
Panel
Lower
Oven
Hinge
Choke Cover
The door on a microwave oven is designed to act
as an electronic seal preventing the leakage of
microwave energy from oven cavity during cook
cycle. This function does not require that door be
air-tight, moisture (condensation)-tight or light-
Pin
Lower
Oven
Hinge
Figure C-6. Door Replacement
MICROWAVE MEASUREMENT
3. Place the load of 275 ± 15ml of water initially at 20
± 5˚C in the centre of the oven tray. The water
container should be a low form of 600 ml beaker with
inside diameter of approx. 8.5cm and made of an
electrically non-conductive 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. Close the door and turn the oven ON with the timer set
for several minutes. If the water begins to boil before
the survey is completed, replace it with 275ml of cool
water.
5. Move the probe slowly (not faster that 2.5cm/sec.)
along the gap.
6. The microwave radiation emission should be measured at any point of 5cm or more from the external
surface of the oven.
After adjustment of door latch switches, monitor switch
and door are completed individually or collectively, the
following leakage test must be performed with a survey
instrument and it must be confirmed that the result meets
the requirements of the performance standard for microwave oven.
REQUIREMENT
The safety switch must prevent microwave radiation emission in excess of 5mW/cm2 at any point 5cm or more from
external surface of the oven.
PREPARATION FOR TESTING:
Before beginning the actual test for leakage, proceed as
follows;
1. Make sure that the test instrument is operating normally as specified in its instruction booklet.
Important:
Survey instruments that comply with the requirement
for instrumentations as prescribed by the performance
standard for microwave ovens must be used for testing.
Recommended instruments are:
NARDA 8100
NARDA 8200
HOLADAY HI 1500
SIMPSON 380M
2. Place the oven tray into the oven cavity.
SHARP
mW cm 2
mW cm 2
Microwave leakage measurement at 5 cm distance
26
THERMAL
CUT-OUT
(OVEN)
N
EARTH
G-Y
27
RY3
RY4
COM.
COM.
1ST.
LATCH SWITCH
Figure O-3(a) Oven Schematic-Grill cooking Condition (TOP HEATER mode)
H.V. RECTIFIER
CONTROUNIT
CAPACITOR
1.07µF
AC2200V
MAGNETRON
FUSE
M10A
T2
H.V. RECTIFIER
CAPACITOR
1.07µF
AC2200V
H.V. FUSE
0.75A
MONITOR SWITCH
N.O.
N.O.
MAGNETRON
HIGH VOLTAGE
TRANSFORMER
T1
N.O.
COM.
MONITOR RESISTOR
0.8/ 20W
GRILL HEATER (TOP)
BOTTOM HEATER
RY4
COM.
CONTROUNIT
HIGH VOLTAGE
TRANSFORMER
T1
RY3
COM.
RY2
RY6
T2
FUSE
M10A
H.V. FUSE
0.75A
N.O.
TTM
TURNTABLE
MOTOR
COM.
N.O.
RY3
RY4
COM.
RY2
RY6
RY5
COM.
COM.
N.O.
H.V. RECTIFIER
CAPACITOR
1.07µF
AC2200V
H.V. FUSE
0.75A
MONITOR SWITCH
N.O.
N.O.
MAGNETRON
HIGH VOLTAGE
TRANSFORMER
T1
N.O.
COM.
MONITOR RESISTOR
0.8/ 20W
GRILL HEATER (TOP)
BOTTOM HEATER
TURNTABLE
MOTOR
TTM
OL
OVEN LAMP
A3
A1
CONTROUNIT
MONITOR RESISTOR
0.8/ 20W
N.O.
N.O.
OL
OVEN LAMP
FM
FAN MOTOR
B2
2ND. INTERLOCK
RELAY CONTROL
B1
SWITCH
NOISE FILTER UNIT
LINE BYPASS CAPACITOR
0.0033µF/ 250V
RESISTOR 10M/ 0.5W
RESISTOR 680 k/ 0.5W
LINE BYPASS CAPACITOR
0.0033µF/ 250V
L
NOISE SUPPRESSION COIL
FUSE 15A
BRN
LIVE
LINE CROSS CAPACITOR
0.22µ/250V
EARTH
G-Y
T2
FUSE
M10A
MONITOR SWITCH
GRILL HEATER (TOP)
BOTTOM HEATER
TURNTABLE
MOTOR
RY2
THERMAL CUT-OUT
(MG.)
COM.
RY5
THERMAL CUT-OUT
(MG.)
COM.
RY6
A3
A1
THERMAL
CUT-OUT
(OVEN)
N
NEUTRAL
220V ~ 50Hz
THERMAL CUT-OUT
(MG.)
TTM
OL
RY2: 2ND. INTERLOCK
RELAY
FM
FAN MOTOR
B2
2ND. INTERLOCK
RELAY CONTROL
B1
SWITCH
NOISE FILTER UNIT
RY2: 2ND. INTERLOCK
RELAY
RY5
THERMAL
CUT-OUT
(OVEN)
LINE BYPASS CAPACITOR
0.0033µF/ 250V
RESISTOR 10M/ 0.5W
RESISTOR 680 k/ 0.5W
LINE BYPASS CAPACITOR
0.0033µF/ 250V
FUSE 15A
L
NOISE SUPPRESSION COIL
LINE CROSS CAPACITOR
0.22µ/250V
EARTH
LIVE
BLU
RY2: 2ND. INTERLOCK
RELAY
OVEN LAMP
A3
A1
LINE BYPASS CAPACITOR
0.0033µF/ 250V
N
G-Y
BRN
220V ~ 50Hz
NOTE:
N.O.
FAN MOTOR
B2
2ND. INTERLOCK
RELAY CONTROL
B1
SWITCH
NOISE FILTER UNIT
LINE BYPASS CAPACITOR
0.0033µF/ 250V
RESISTOR 10M/ 0.5W
RESISTOR 680 k/ 0.5W
NOISE SUPPRESSION COIL
FUSE 15A
L
NEUTRAL
BLU
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2.
:
OR CLOCK APPEAR ON DISPLAY.
FM
LIVE
BRN
220V ~ 50Hz
LINE CROSS CAPACITOR
0.22µ/250V
NEUTRAL
BLU
R-770B
Indicates components with potential above 250 V.
1ST.
LATCH SWITCH
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSE.
2. MICROWAVE POWER LEVEL PAD PRESSED ONCE(100%).
3. COOKING TIME PROGRAMMED.
4. STRAT PAD PRESSED.
Figure O-1 Oven Schematic-OFF Condition
1ST.
LATCH SWITCH
Figure O-2 Oven Schematic-Microwave cooking Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSE.
2. GRILL PAD PRESSED ONCE.
3. COOKING TIME PROGRAMMED.
4. STRAT PAD PRESSED.
THERMAL
CUT-OUT
(OVEN)
N
BLU
EARTH
G-Y
28
RY3
RY4
COM.
COM.
1ST.
LATCH SWITCH
Figure O-3(c) Oven Schematic-Grill cooking Condition (TOP AND BOTTOM HEATERS mode)
H.V. RECTIFIER
CAPACITOR
1.07µF
AC2200V
CONTROUNIT
MAGNETRON
HIGH VOLTAGE
TRANSFORMER
T1
T2
FUSE
M10A
H.V. FUSE
0.75A
N.O.
RY3
RY4
COM.
RY2
RY6
COM.
COM.
N.O.
H.V. RECTIFIER
CAPACITOR
1.07µF
AC2200V
H.V. FUSE
0.75A
MONITOR SWITCH
N.O.
N.O.
MAGNETRON
HIGH VOLTAGE
TRANSFORMER
T1
N.O.
COM.
MONITOR RESISTOR
0.8/ 20W
GRILL HEATER (TOP)
BOTTOM HEATER
TURNTABLE
MOTOR
TTM
OL
OVEN LAMP
RY5
CONTROUNIT
MONITOR RESISTOR
0.8/ 20W
N.O.
N.O.
COM.
A3
L
T2
FUSE
M10A
MONITOR SWITCH
GRILL HEATER (TOP)
BOTTOM HEATER
TURNTABLE
MOTOR
RY2
RY6
THERMAL CUT-OUT
(MG.)
COM.
N.O.
FM
FAN MOTOR
A1
THERMAL CUT-OUT
(MG.)
TTM
OL
OVEN LAMP
RY2: 2ND. INTERLOCK
RELAY
RY5
RY2: 2ND. INTERLOCK
RELAY
A3
B2
2ND. INTERLOCK
RELAY CONTROL
B1
SWITCH
NOISE FILTER UNIT
LINE BYPASS CAPACITOR
0.0033µF/ 250V
RESISTOR 10M/ 0.5W
RESISTOR 680 k/ 0.5W
LINE BYPASS CAPACITOR
0.0033µF/ 250V
FUSE 15A
NOISE SUPPRESSION COIL
LINE CROSS CAPACITOR
0.22µ/250V
EARTH
G-Y
LIVE
BRN
220V ~ 50Hz
NOTE:
FM
FAN MOTOR
B2
A1
THERMAL
CUT-OUT
(OVEN)
N
NEUTRAL
BLU
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSE.
2. GRILL PAD PRESSED TWICE.
3. COOKING TIME PROGRAMMED.
4. STRAT PAD PRESSED.
2ND. INTERLOCK
RELAY CONTROL
B1
SWITCH
NOISE FILTER UNIT
LINE BYPASS CAPACITOR
0.0033µF/ 250V
RESISTOR 10M/ 0.5W
RESISTOR 680 k/ 0.5W
LINE BYPASS CAPACITOR
0.0033µF/ 250V
L
NOISE SUPPRESSION COIL
FUSE 15A
BRN
LIVE
LINE CROSS CAPACITOR
0.22µ/250V
NEUTRAL
220V ~ 50Hz
R-770B
Indicates components with potential above 250 V.
1ST.
LATCH SWITCH
Figure O-3(b) Oven Schematic-Grill cooking Condition (BOTTOM HEATER mode)
SCHEMATIC
NOTE: CONDITION OF OVEN FOR GRILL COOKING
1. DOOR CLOSE.
2. GRILL PAD PRESSED TREE TIMES.
3. COOKING TIME PROGRAMMED.
4. STRAT PAD PRESSED.
R-770B
Indicates components with potential above 250 V.
MONITOR RESISTOR
0.8/ 20W
MAGNETRON
H.V. RECTIFIER
CAPACITOR
1.07µF
AC2200V
H.V. FUSE
0.75A
BOTTOM HEATER
MONITOR SWITCH
RY4
COM.
TURNTABLE
MOTOR
TTM
COM.
N.O.
OL
OVEN LAMP
GRILL HEATER (TOP)
RY3
COM.
RY2
RY6
A3
FM
FAN MOTOR
B2
2ND. INTERLOCK
RELAY CONTROL
B1
SWITCH
RY2: 2ND. INTERLOCK
RELAY
RY5
A1
N.O.
CONTROUNIT
HIGH VOLTAGE
TRANSFORMER
T2
T1
FUSE
M10A
N.O.
N.O.
COM.
NOTE: RY2 and RY3 could not turn on simultaneously.
THERMAL CUT-OUT
(MG.)
NOISE FILTER UNIT
LINE BYPASS CAPACITOR
0.0033µF/ 250V
NOTE:
THERMAL
CUT-OUT
(OVEN)
N
LINE BYPASS CAPACITOR
0.0033µF/ 250V
RESISTOR 10M/ 0.5W
NOISE SUPPRESSION COIL
L
FUSE 15A
LINE CROSS CAPACITOR
0.22µ/250V
EARTH
BRN
LIVE
NEUTRAL
G-Y
220V ~ 50Hz
BLU
RESISTOR 680 k/ 0.5W
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSE.
2. GRILL MIX PAD PRESSED ONCE FOR GRILL MIX HIGH WITH TOP HEATER.
GRILL MIX PAD PRESSED TWICE FOR GRILL MIX LOW WITH TOP HEATER.
3. COOKING TIME PROGRAMMED.
4. STRAT PAD PRESSED.
1ST.
LATCH SWITCH
Figure O-4(a) Oven Schematic-Grill Mix cooking Condition
(Grill Mix High with Top Heater mode and Grill Mix Low with Top Heater mode)
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSE.
2. GRILL MIX PAD PRESSED THREE TIMES FOR GRILL MIX HIGH WITH BOTTOM HEATER.
GRILL MIX PAD PRESSED FOUR TIMES FOR GRILL MIX LOW WITH BOTTOM HEATER.
3. COOKING TIME PROGRAMMED.
4. STRAT PAD PRESSED.
THERMAL
CUT-OUT
(OVEN)
1ST.
LATCH SWITCH
Figure O-4(b) Oven Schematic-Grill Mix cooking Condition
(Grill Mix High with Bottom Heater mode and Grill Mix Low with Bottom Heater mode)
29
H.V. RECTIFIER
MAGNETRON
HIGH VOLTAGE
TRANSFORMER
H.V. FUSE
0.75A
BOTTOM HEATER
MONITOR SWITCH
RY4
COM.
TURNTABLE
MOTOR
TTM
COM.
GRILL HEATER (TOP)
N.O.
RY3
COM.
RY2
RY6
OL
OVEN LAMP
N.O.
A3
FM
FAN MOTOR
B2
RY5
A1
2ND. INTERLOCK
RELAY CONTROL
B1
SWITCH
RY2: 2ND. INTERLOCK
RELAY
MONITOR RESISTOR
0.8/ 20W
T2
T1
N.O.
N.O.
COM.
CONTROUNIT
NOISE FILTER UNIT
LINE BYPASS CAPACITOR
0.0033µF/ 250V
LINE BYPASS CAPACITOR
0.0033µF/ 250V
RESISTOR 10M/ 0.5W
NOISE SUPPRESSION COIL
RESISTOR 680 k/ 0.5W
FUSE 15A
LINE CROSS CAPACITOR
0.22µ/250V
EARTH
THERMAL CUT-OUT
(MG.)
FUSE
M10A
N
NEUTRAL
G-Y
LIVE
BRN
BLU
220V ~ 50Hz
L
NOTE: RY2 and RY4 could not turn on simultaneously.
1
2
H
3
30
ORG
RED
RED
BRN
G
RY2
RY4
RY3
SP1
4
5
WHT
WHT
WHT
GRY
WHT
GRY
WHT
WHT
CONNECTOR
RED
TURNTABLE
MOTOR
BOTTOM HEATING
ELEMENT
Figure S-1. Pictrorial Diagram
COM.
N.O.
1ST.
LATCH
SWITCH
WHT
BLK
WHT
RED
L
T1
BRN
RED
WHT
WHT
QRG
N
LIVE
M10A
FAN MOTOR
ORG
GRY
GRY
RED
BRN
THERMAL
CUT-OUT
125°C(MG)
RED
WHT
HIGH VOLTAGE
TRANSFORMER
H.V. FUSE
H.V.
RECTIFIER
MAGNETRON
H.V.
CAPACITOR
HIGH VOLTAGE COMPONENTS
BRN
T2
BLU
4
ORG
BRN
RY5
COM
WHT
GRY
MONMITOR
SWITCH
N.C.
GRY
MONITOR
RESISTOR
EARTH
NOISE
FILTER
BRN
G–Y
POWER SUPPLY
CORD
A
3 ORG
2
1 GRY
CN-A
BRN
ORG
ORG
RED
OVEN LAMP
(HALOGEN LAMP)
WHT
3
BLK
CN-A
T1
RY6
CN-B
CN-B
2 GRY
1 GRN
WHT
THERMAL
CUT-OUT
(OVEN)
WHT
2
ORG
BLK
CN-C
CN-C
COM.
GRY
GRN
N.O.
BLK
GRY
D
CONTROL PANEL
CN-G
F
2ND.
INTERLOCK
RELAY
CONTROL
SWITCH
E
NEUTRAL
WHT
1
15A
B
RED WHT
C
GRILL HEATER
R-770B
5
6
A
B
C
D
6
E
F
G
H
R-770B
2
1
4
3
6
5
A
A
Q2 2SB1238
R4 27
D1-4
11ES1
C3
VC
C1
VA
C9
VR
C4
INT
C5
BUZZER
C15
FAN MOTOR
+
–
R2 510 1/2w
SP1
RY5
C
R6 3.3k
D12
FAN MOTOR
GND
R3 510 1/2w
c
C
C2
C4 10µ/35v
D2
C3 0.1µ/50v
D4
b
(J1)
a
LED
B
+
6
d 1
C10
R5 4.7k
D1
D3
–
10G471K
VRS1
AC220V
50Hz
4
D6
C2 470µ/50v
8
A1
B
D5
C1 0.1µ/50v
T1
A3
D
D
RY6
N.C.
C6
OVEN LAMP
TURNTABLE
MOTOR
C14
BOTTOM
HEATER
C8
TOP
HEATER
C11
N.C.
C7
MICRO
C17
N.C.
C13
N.C.
C12
DOOR
SWITCH
Q3
KRC243M
D11
COM
–
+
OVEN LAMP
TURNTABLE
MOTOR
C16
N.O.
C5
10µ/35v
RY4
BOTTOM
HEATER
D10
E
N.O.
E
COM
RY3
TOP
HEATER
D9
N.O.
COM
RY2
F
D8
N.O.
MICRO
COM
B2
F
B1
DOOR SWITCH
G
G
: IF NOT SPECIFIED, 1/4w ± 5%
NOTE
: IF NOT SPECIFIED, 1SS270A
H
H
Figure S-2. Power Unit Circuit
1
2
4
3
31
5
6
C9
C15
VR
FAN
MOTOR
C7
BOTTOM
HEATER
MICRO
DOOR
SWITCH
C14
5
C17
C13
C12
G
D30
D23
D22
+
C10 47µ/16v
C11 0.1µ/50v
Q20
DTA123JKA
Q21
DTA123JKA
Q22
DTA123JKA
C21
0.1µ/50v
Q23
DTA143EKA
Q25
DTA143EKA
LD10 LD9 LD8 LD7 LD6
LD1 LD2 LD3 LD4 LD5
Q40
DTA143EKA
–
C13
0.1µ/50v
R30 4.7k
C30
R10 1k
(J10) 4.7k
(J11)
(J12)
(J13)
(J15) 4.7k
R11 4.7k
(J14) 4.7k
ZD10
UDZ4.3B
Q10
2SA1037AK
C1
VL1
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
P57
P56
P55
P54
P53
P52
P51
P50
P47
P46
P45
P44
INT1
INT0
P41
P40
P77
P76
P75
P74
51
30
25
20
15
10
5
R56
1M
CF1
4.19
MHz
EASY
DEFROST
8
9
GRILL
MIX
0
INSTANT
COOK/START
G6
3
G7
4
5
G8
HELP
GRILL
6
STEAM
MENU
REHEAT
G3
CRISPY
SNACK
AUTO
GRILL
7
1
2
POWER
LEVEL
G4
G5
80 SEG10
SEG11
SEG12
SEG13
SEG14
75 SEG15
SEG16
SEG17
SEG18
SEG19
70 SEG20
SEG21
SEG22
SEG23
SEG24
65 SEG25
SEG26
SEG27
SEG28
SEG29
60 SEG30
SEG31
SEG32
SEG33
SEG34
55 SEG35
SEG36
SEG37
SEG38
SEG39
SLOW
COOK
G2
AUTO
COOK
RICE
COOK
G1
STOP/
CLEAR
PIZZA
1
5
R70 15k
R14
15k
R15 4.7k
C14
Figure S-3. Control Panel Circuit
C63 330p/50v
C62 330p/50v
C61 330p/50v
C60 330p/50v
R75 100k
R74 100k
R73 100k
R72 100k
R69 15k
Q11
DTA143EKA
90
R13
15k
%
KG PCS AUTO COOK
4
C11
C8
TOP
HEATER
OVEN LAMP
TURNTABLE
C6
MOTOR
C16
C1
C10
C5
BUZZER
LED
C3
VC
VA
C2
GND
R31 15k
C4
G12 G11 G10 G 9
INT
R63 15k
: IF NOT SPECIFIED, 0.01µF / 25v
R64 15k
: IF NOT SPECIFIED, 1SS355
95
R55 4.7k
C81
15p/50v
32
R60 15k
4
(J1)
680F
3
C82
15p/50v
C12
0.1µ/50v
R68 15k
C2
VL2
VL3
COM0
COM1
COM2
COM3
AVSS
VREF
VCC
SEG0
SEG1
SEG2
SEG3
SEG4
SEG5
SEG6
SEG7
SEG8
SEG9
85
E
IC-1
RH-IZA859DR
2
3
R61 15k
R12
15k
TURNOVER ADD STAND COVER STIR DEFROST HELP
R65 15k
: IF NOT SPECIFIED, 1/10w ± 5%
R66 15k
1
R67 15k
F
SEG39
SEG38
SEG37
SEG36
SEG35
SEG34
SEG33
SEG32
SEG31
NC
NC
NC
NC
NC
NC
NC
COM3
COM2
COM1
NC
NC
SEG30
SEG29
SEG28
SEG27
SEG26
SEG25
SEG24
SEG23
SEG22
SEG21
SEG20
SEG19
SEG18
SEG17
SEG16
SEG15
SEG14
SEG13
SEG12
SEG11
SEG10
SEG9
SEG8
SEG7
SEG6
SEG5
SEG4
SEG3
SEG2
SEG1
B
R71 15k
C
2
P73
P72
P71
P70
RESET 35
P81
P80
XIN
XOUT
VSS
P27
P26
P25
P24
45
P23
P22
P21
P20
P17
50
P16
1
R62 15k
NOTE
R-770B
6
A
A
B
C
D
D
H
6
E
F
G
H
R-770B
2
1
4
3
6
5
A
A
DIP
R3
CN - C 18
B
1
1
2
D6
3
Q1
B
3
D5
1
CN - B
4
D11
RY6
1
R1
E
R2
C2
AC
B
2
ZD1
C5
E
Q3
SP1
C
CN - D
R4
E
Q2
R5
B
D8
C3
C4
R6
D9
D10
B
C
D1
D3
C1
RY3
T-H
D
D
1
D2
8
RY4
B-H
D4
RY2
MICRO
E
E
6
S
F
T1
5
(J1)
F
P
4
VRS1
FAN
1
5
CON
AC
G
D7
CN - A
6
LOT NO.
D12
RY1
G
RY5
F
H
H
Figure S-4. Printed Wiring Board
1
2
4
3
33
5
6
R-770B
PARTS LIST
Note: The parts marked "∆" may cause undue microwave exposure.
The parts marked "*" are used in voltage more than 250V.
REF. NO.
PART NO.
DESCRIPTION
Q'TY
CODE
2
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
AK
AK
AU
AT
AM
AY
AY
AW
AW
AT
AF
AE
AD
AX
BD
BB
AK
AH
AK
BR
BN
BN
AQ
1
1
1
2
AW
AZ
AX
AC
1
1
1
1
1
1
1
2
4
2
5
1
1
2
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
4
BF
AB
AB
AF
AB
AE
AB
AB
AB
AA
AA
AA
AB
AB
AB
AA
AA
AL
AK
AG
AK
AG
AS
AE
BC
BE
AF
AB
AW
AL
AE
AA
1
1
1
1
1
1
1
BU
AL
BB
AY
AP
AE
AN
ELECTRIC PARTS
*
*
*
*
∆*
∆*
*
1- 1
1- 2
1- 3
1- 3
1- 4
1- 5
1- 5
1- 6
1- 7
1- 8
1- 9
1-10
1-11
1-12
1-13
1-14
1-15
1-16
1-17
1-18
1-19
1-19
1-20
QSW-MA110WRE0
QSW-MA111WRE0
RMOTDA228WRE0
RMOTDA207WRE0
FH-DZA080WRK0
RC-QZA215WRE0
RC-QZA182WRE0
RMOTEA361WRE0
FPWBFA317WRK0
QACC-A067WRE0
QFS-BA007WRE0
QFS-CQ001YBE0
QTANNA017WRW0
RHET-A200WRE0
RHET-A201WRE0
RLMPUA001WRE0
RR-WZA022WRE0
RTHM-A048WRE0
RTHM-A078WRE0
RTRN-A555WRE0
RV-MZA222WRE0
RV-MZA197WRE0
QFS-IA002WRE0
1st. latch switch and 2nd. interlockrelay control switch
Monitor switch
Turntable motor
Turntable motor (Interchangeable)
High voltage rectifier assembly
High voltage capacitor
High voltage capacitor (Interchangeable)
Fan motor
Noise filter
Power supply cord
Fuse 15A
Fuse 10A
Short terminal
Grill heater (Top heater)
Bottom heater
Oven lamp (Halogen lamp)
Monitor resistor 0.8 ohm 20W
Thermal cut out 170˚C OFF / 155˚C ON
Thermal cut-out 125˚C
High voltage transformer
Magnetron
Magnetron (Interchangeable)
High voltage fuse 0.75A
2222-
1
2
3
4
GCABDA092WRW0
GCABUA649WRP0
GDAI-A305WRW0
GLEGPA074WRE0
Back plate
Outer case cabinet
Base plate
Leg
3- 1
3- 1A
3- 1B
3- 1C
C1
C2
C3
C4-5
D1-4
D5-6
D8-12
Q2
Q3
R2-3
R4
R5
R6
RY2
RY3-4
RY5
RY6
SP1
T1
VRS1
3- 2
3- 3
3- 3-1
3- 3-2
3- 3-3
3- 4
3- 5
3- 6
CPWBFA780WRK0
QCNCMA244DRE0
QCNCMA275DRE0
FW-VZA230DRE0
RC-KZA087DRE0
VCEAB31HW477M
RC-KZA087DRE0
VCEAB31VW106M
VHD11ES1///-1
VHD1SS270A/-1
VHD1SS270A/-1
VS2SB1238//-3
VSKRC243M//-3
VRD-B12HF511J
VRD-B12EF270J
VRD-B12EF472J
VRD-B12EF332J
RRLY-A081DRE0
RRLY-A076DRE0
RRLY-A080DRE0
RRLY-A076DRE0
RALM-A014DRE0
RTRNPA105DRE0
RH-VZA032DRE0
CPWBFA787WRK0
DPNLCB491WRK0
JBTN-B086WRF0
MSPRCA050WRE0
FUNTKA861WRE0
LHLD-A185WRF0
PSHEPA624WRE0
XEPSD30P08XS0
Power unit
2-pin connector (CN-A)
2-pin connector (CN-B)
15pin wire harness (WH-1)
Capacitor
0.1 uF
50V
Capacitor
470 uF
50V
Capacitor
0.1 uF
50V
Capacitor
10 uF
35V
Diode (11ES1)
Diode (1SS270A)
Diode (1SS270A)
Transistor (2SB1238)
Transistor (KRC243M)
Resistor
510 ohm
1/2W
Resistor
27 ohm
1/4W
Resistor
4.7k ohm
1/4W
Resistor
3.3k ohm
1/4W
Relay (VRB24)
Relay (OMIF-S-124LM)
Relay (OJ-SH-124LM)
Relay (OMIF-S-124LM)
Buzzer (PKM22EPT-THAI)
Transformer
Varistor (10G471K)
CPU unit
Control panel frame with key unit
Open button
Open button spring
Key unit
LCD holder
LED sheet
Screw; 3mm x 8mm
4444444-
DOVN-A487WRY0
PHOK-A106WRF0
PDUC-A695WRP0
PSKR-A333WRP0
LANGQA478WRP0
MSPRTA186WRE0
NCPL-A051WRE0
Oven cavity
Latch hook
Air duct
Partition plate
Turntable motor angle
Plate spring
Turntable motor shaft
CABINET PARTS
CONTROL PANEL PARTS
OVEN PARTS
∆
∆
1
2
3
4
5
6
7
34
R-770B
Note: The parts marked "∆" may cause undue microwave exposure.
The parts marked "*" are used in voltage more than 250V.
REF. NO.
PART NO.
DESCRIPTION
4- 8
4- 9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20
4-21
4-22
4-23
4-24
4-25
4-26
4-27
4-28
4-29
4-30
4-31
4-32
4-33
PSPA-A109WRE0
LBNDKA136WRP0
NFANJA041WRE0
PDUC-A697WRF0
GCOVHA388WRW0
GLEGPA071WRF0
LANGFA185WRP0
LANGQA480WRP0
LFLG-A025WRE0
MLEVPA226WRF0
MSPR-A004WRE0
PCOV-A011WRP0
PCOVPA339WRE0
PCUSGA385WRP0
PCUSUA190WRP0
PCUSUA191WRP0
PDUC-A691WRF0
PDUC-A692WRP0
PDUC-A696WRP0
PGLSPA506WRE0
PCUSGA399WRE0
PREFHA061WRW0
PSHEPA487WRE0
PSKR-A331WRP0
MSPRCA113WRE0
PCUSGA420WRP0
Spacer
HV capacitor holder
Fan blade
Fan duct
Bottom heater cover
Leg
Chassis support
Lamp cover
Bearing
Switch lever
Heat seal spring
Bottom heater angle
Waveguide cover
Cushion
Cushion
Cushion
Air intake duct
Exhaust
Air guide
Light glass
Cushion
Reflector
Heater film
Air separate angle
H-spring
Cushion
∆ 5- 1
∆ 5- 2
∆ 5- 3
5- 4
5- 5
5- 6
5- 7
5- 8
5- 9
DDORFA857WRK0
GWAKPA544WRR0
LSTPPA176WRF0
LSTPPA177WRF0
MSPRTA187WRE0
PGLSPA508WRE0
XCPSD40P06000
XCPSD40P08000
GCOVHA387WRF0
Door panel assembly
Door frame
Latch head
Glass stopper
Latch spring
Front door glass
Screw : 4mm x 6mm
Screw : 4mm x 8mm
Choke cover
Q'TY
CODE
1
1
1
1
1
1
1
1
1
1
2
2
1
2
1
1
1
1
1
1
1
1
1
1
1
1
AB
AQ
AF
AM
AF
AG
AM
AX
AM
AF
AF
AM
AF
AH
AC
AC
AG
AS
AT
AN
AF
BE
AA
AY
AC
AE
1
1
1
1
1
1
2
4
1
BB
AX
AN
AF
AC
AV
AA
AA
AS
1
1
1
1
1
1
1
1
1
1
1
1
1
AS
AS
BC
AZ
AX
AL
AG
BA
AN
AB
AC
AC
AC
14
2
2
4
2
1
1
3
13
7
2
1
AA
AA
AB
AA
AA
AB
AA
AA
AA
AA
AA
AA
DOOR PARTS
MISCELLANEOUS
6- 1
6- 2
6- 3
6- 4
6- 5
6- 6
6- 7
6- 8
6- 9
6-10
6-11
6-15
6-16
FAMI-A099WRM0
FAMI-A100WRM0
FSRAHA062WRY0
NTNT-A092WRH0
TCADCA640WRR0
TINSEA749WRR0
FW-VZB045WRE0
FW-VZB651WRE0
TCADCA641WRR0
LHLDWA011WRE0
TCAUHA214WRR0
TSPCNC572WRR0
TCAUHA240WRR0
High rack
Low rack
Turntable support
Turntable
Cook book for microwave
Instruction book
Switch harness
Main wire harness
Cookbook in russian
Purse lock M
K caution label
Rating label
Lamp caution
SCREWS,NUTS AND WASHERS
7- 1
7- 2
7- 3
7- 4
7- 5
7- 6
7- 7
7- 8
7- 9
7-10
7-11
7-12
XFPSD40P08K00
XEPSD40P25000
LX-EZA042WRE0
LX-NZ0061WRE0
XBPWW30P05K00
XCTWW40P08000
XHPSD30P06000
XHTSD40P08RV0
XOTSD40P12RV0
XOTSD40P12000
XOTSD40R12RV0
XOTSE40P08000
Screw : 4mm x 8mm
Screw : 4mm x 25mm
Special screw
Flange nut
Screw : 3mm x 5mm
Screw : 4mm x 8mm
Screw : 3mm x 6mm
Screw : 4mm x 8mm
Screw : 4mm x 12mm
Screw : 4mm x 12mm
Line head screw : 4mm x 12mm
Screw : 4mm x 8mm
HOW TO ORDER REPLACEMENT PARTS
To have your order filled prompty and correctly, please furnish the following information.
1. MODEL NUMBER
2. REF. NO.
3. PART NO.
35
4. DESCRIPTION
R-770B
2
1
4
3
6
5
OVEN AND CABINET PARTS
2-2
A
A
7-9
4-25
4-33
7-11
7-10
B
6-11
2-1
7-11
7-10
4-23
4-26
B
4-29
4-4
7-10
7-5
7-12
7-10
7-4
C
1-11
4-30
1-12
4-19
C
7-1
1-16
4-15
4-3
4-31
1-8
4-18
4-32
1-14
4-24
4-27
7-8
1-9
1-15
D
1-17
4-1
7-1
7-8
7-7
D
1-10
7-10
7-6
4-14
1-13
4-16
6-7
7-1
7-1
E
4-20
4-6
4-18
4-32
4-19
7-4
4-2
4-8
6-4
4-21
1-1
1-6
7-2
1-20
7-9
4-7
1-7
4-11
E
1-5
4-5
1-2
1-3
7-1
1-4
4-12
7-1
1-1
F
F
7-3
1-19
4-17
7-1
6-3
4-10
4-9
7-1
1-18
7-1
4-22
4-28
G
G
2-3
7-9
2-4
4-13
H
2-4
7-9
H
7-9
1
2
4
3
36
5
6
R-770B
2
1
4
3
5
6
3-6
CONTROL PANEL PARTS
3-4
A
A
3-5
3-2
3-3
3-6
B
B
3-3-3
6-12
3-1
C
C
DOOR PARTS
3-3-1
D
D
5-8
3-3-2
5-9
5-1
E
E
5-6
5-2
5-4
5-7
F
F
5-3
5-5
MISCELLANEOUS
G
G
6-1
6-8
6-7
6-2
Actual wire harness may be different than illustration.
6-10
H
H
1
2
4
3
37
5
6
R-770B
PACKING AND ACCESSORIES
TOP PAD ASSEMBLY
TRAY HOLDER
(FPADBA373WRK0)
(SPADFA424WRE0)
TURNTABLE TRAY
WRAP COVER
HIGH RACK
(SSAKHA034WRE0)
LOW RACK
DOOR PROTECTION SHEET
(SPADPA204WRE0)
LAMP CAUTION
COOK BOOK &
INSTRUCTION BOOK
BOTTOM PAD ASSEMBLY
TURNTABLE SUPPORT
(FPADBA374WRK0)
TRAY PAD
(SPADPA577WRE0)
PACKING CASE
Not Replaceable Items.
(SPAKCD046WRE0)
'98SHARP CORP. (03K0.120E) Printed in Japan
38