Sharp R-8740 (serv.man17) Service Manual ▷ View online
R-8740M - 3
®
GRILL AND CONVECTION MICROWAVE OVEN
R-8740M
GENERAL IMPORTANT INFORMATION
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.
SERVICE MANUAL
WARNING
Never operate the oven until the following points are ensured.
(A) The door is tightly closed.
(B) The door and oven 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.
(A) The door is tightly closed.
(B) The door and oven 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.
Service Engineers.
All the parts marked ”*” on parts list are used at voltages more
than 250V.
than 250V.
Removal of the outer wrap gives access to potentials above
250V.
250V.
All the parts marked "∆" on the parts list may cause undue
microwave exposure, by themselves, or when they are dam-
aged, loosened or removed.
microwave exposure, by themselves, or when they are dam-
aged, loosened or removed.
SHARP CORPORATION
OSAKA, JAPAN
WARNING
MICROWAVE RADIATION
Personnel 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.
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.
R-8740M - 4
SERVICING
CAUTION
MICROWAVE RADIATION
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.
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
THIS APPLIANCE MUST BE EARTHED
. THE WIRES IN THIS MAINS LEAD ARE COLOURED IN
ACCORDANCE WITH THE FOLLOWING CODE:
GREEN-AND-YELLOW : EARTH BLUE : NEUTRAL BROWN : LIVE
GREEN-AND-YELLOW : EARTH BLUE : NEUTRAL BROWN : LIVE
WARNING
Servicing and repair work must be carried out only by
trained service engineers.
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.
trained service engineers.
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.
CAUTION/WARNING
REMEMBER TO CHECK 3D
1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge high voltage capacitor.
2) Door opened, and wedged open.
3) Discharge high voltage capacitor.
WARNING: AGAINST THE CHARGE OF THE HIGH-
VOLTAGE CAPACITOR
The high-voltage capacitor remains charged about 60 sec-
onds 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.
onds 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.
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.
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 wires.
result in electrocution.
High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier assembly, High voltage wires.
REMEMBER TO CHECK 4R
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.
testing.
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run the oven. Check all functions.
Microwave ovens should not be run empty. To test for the
presence of microwave energy within a cavity, place a cup of
cold water on the oven turntable, close the door and set the
power to HIGH and set the microwave timer for two (2) minutes.
When the two minutes has elapsed (timer at zero) carefully
check that the water is now hot. If the water remains cold carry
out 3D checks and re-examine the connections to the compo-
nent being tested.
presence of microwave energy within a cavity, place a cup of
cold water on the oven turntable, close the door and set the
power to HIGH and set the microwave timer for two (2) minutes.
When the two minutes has elapsed (timer at zero) carefully
check that the water is now hot. If the water remains cold carry
out 3D checks and re-examine the connections to the compo-
nent being tested.
When all service work is completed, and the oven is fully
assembled, the microwave power output should be checked and
a microwave leakage test should be carried out.
assembled, the microwave power output should be checked and
a microwave leakage test should be carried out.
R-8740M - 5
ITEM
DESCRIPTION
Power Requirements
230-240V Volts / 50 Hertz / Single phase, 3 wire earthed
Power Consumption
Microwave cooking
1.45kW Approx. 6.3A
Dual cooking
(Microwave and Top Grill)
2.4kW Approx. 10.3A
(Microwave and Bottom Grill)
1.95kW Approx. 8.2A
(Top and Bottom Grill) 1.5kW Approx. 6.3A
Convection cooking
1.525kW Approx. 6.4A
Bottom Grill cooking
550kW Approx. 2.3A
Top Grill cooking
1000kW Approx. 4.2A
Power Output
900 watts nominal of RF microwave energy (measured by method of IEC
60705) Operating fequency 2450 MHz
60705) Operating fequency 2450 MHz
Top Grill heating element Power Output
1000W
Bottom Grill heating element Power Output
500W
Case Dimensions
Width 520 mm
Height 309 mm (including foot)
Depth 488 mm
Cooking Cavity Dimensions
Width 349 mm
Height 207 mm
Depth 357 mm
Turntable diameter
325mm
PRODUCT DESCRIPTION
Net Weight
Approx. 19 kg
Control Complement
1. DIGITAL DISPLAY
2. INDICATORS:
2. INDICATORS:
These indicators will light corresponding with
below symbols
below symbols
: Time reduce
: Memory
: Manual
: Percentage (for microwave
power level)
power level)
: Lock (showing oven lock is set)
: Cook (showing oven in operation)
3. COOKING MODE indicator lights.
These indicator lights will light during
each cooking mode.
each cooking mode.
SPECIFICATION
As part of our policy of continuous improvement, we reserve the right to
alter design and specifications without notice
alter design and specifications without notice
4. NUMBER keys for time and memory
programming
5. START key
6. STOP key
7. SOUND key
8. BOTTOM GRILL key
9. TOP GRILL key
6. STOP key
7. SOUND key
8. BOTTOM GRILL key
9. TOP GRILL key
10. CONVECTION key
To change the convection
temperature
temperature
11. MICROWAVE key
To change the microwave power
setting
setting
12. MANUAL key
13. MEMORY key
14. TIME REDUCE key
13. MEMORY key
14. TIME REDUCE key
OPERATION KEYS:
Note:
Temperature measurements taken whilst the oven is in convection mode will differ from the displayed level.
This is due to the grill elements turning on and off in order to regulate the oven temperature.
This will not affect the cooking results as long as the operation manual and cook book are followed correctly.
Temperature measurements taken whilst the oven is in convection mode will differ from the displayed level.
This is due to the grill elements turning on and off in order to regulate the oven temperature.
This will not affect the cooking results as long as the operation manual and cook book are followed correctly.
R-8740M - 6
APPEARANCE VIEW
OVEN
1. DIGITAL DISPLAY
2. INDICATORS:
2. INDICATORS:
These indicators will light corresponding with
below symbols
below symbols
: Time reduce
: Memory
: Manual
: Percentage (for microwave
power level)
power level)
: Lock (showing oven lock is set)
: Cook (showing oven in operation)
3. COOKING MODE indicator lights.
These indicator lights will light during
each cooking mode.
each cooking mode.
OPERATION KEYS:
4. NUMBER keys for time and memory
programming
5. START key
6. STOP key
7. SOUND key
8. BOTTOM GRILL key
9. TOP GRILL key
10. CONVECTION key
6. STOP key
7. SOUND key
8. BOTTOM GRILL key
9. TOP GRILL key
10. CONVECTION key
To change the convection temperature
11. MICROWAVE key
To change the microwave power setting
12. MANUAL key
13. MEMORY key
14. TIME REDUCE key
13. MEMORY key
14. TIME REDUCE key
14
13
12
11
10
9
8
7
6
1
2
2
3
4
5
9
7
10
4
1
8
6
5
3
2
10
12
11
9. Door seals and sealing surfaces
10. Ventilation openings
11. Outer cabinet
12. Power supply cord
13. Turntable
14. Handle
10. Ventilation openings
11. Outer cabinet
12. Power supply cord
13. Turntable
14. Handle
1. Control panel
2. Oven lamp
3. Grill heating element (Top Grill)
4. Door opening button
5. Waveguide cover
6. Oven cavity
7. Turntable motor shaft
8. Grill heating element
2. Oven lamp
3. Grill heating element (Top Grill)
4. Door opening button
5. Waveguide cover
6. Oven cavity
7. Turntable motor shaft
8. Grill heating element
(Bottom Grill)
14
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