Sharp R-9370 User manual

R-9370
SHARP SERVICE MANUAL
S7607R9370J//
MICROWAVE OVEN
MODEL R-9370
In the interests of user-safety the set should be restored to its
original condition and only #parts identical to those specified be
used.
This isa supplemental Service Manual for R-9370.
This model is quite similar to Base Model R-9360.
Model R-9370 has Reheat Sensor function in addition, compared to its base model R-9360.
Use this supplemental manual together with the BaseService Manual.
Refer to the Base Service Manual for complete operation, service information, etc.
cc TABLE OF CONTENTS Y
Page
FOREWORD ...................................................................... 1
CAUTION, MICROWAVE RADIATION ................................................... 1
THUMB INDEX ................................................................... 1
PRODUCT DESCRIPTION ............................................................ 2
OPERATING INSTRUCTIONS ......................................................... 3
SERVICING ....................................................................... 6
TOUCH CONTROL PANEL ASSEMBLY. ................................................. 8
MICROWAVE MEASUREMENT ....................................................... 21
SCHEMATIC DIAGRAM ............................................................ 22
PICTORIAL DIAGRAM ............................................................. 22
CONTROL PANEL CIRCUIT ......................................................... 23
PRINTED WIRING BOARD .......................................................... 24
PARTS LIST .................................................................... 25
PACKING AND ACCESSORIES.. ..................................................... 34
SHARP CORPORATION

R-9370
SERVICE MANUAL
SHARP
MICROWAVE OVEN
R-9370
FOREWORD
This Manual has been prepared to provide Sharp Service
Personnel with complete Operation and Service information
for the Sharp Microwave Oven.
This model isquite similar to Base Model R-9360.
(Ref. No. SO506R936OJ//).
It is recommended that service personnel carefully study the
entire text of two Manuals (Base manual and this manual),
so they will be qualified to render satisfactory customer
service.
CAUTION
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 ‘devicewithout a microwave energy absorbing
load attached.
Never look into an open waveguide or antenna while the
device is energized.
SHARP CORPORATION
OSAKA, JAPAN

R-9370 PRODUCT DESCRIPTION
EXPLANATION OF MICROWAVE COOKING
‘Xhe Sharp Microwave Oven usesmicrowave energy to produce
heat in the food to be cooked. Unlike conventional ovens
microwave energy will cook foods without applying external
heat.
Microwaves, which are short electromagnetic waves of RF
(radio frequency) energy, passthrough materials such as glass,
paper, china and most plastics. Materials such as metal and
aluminum foil tend to reflect microwaves and may be used
only as recommended in the cooking instructions.
Materials with a high moisture content, like most foods, will
absorb microwave energy. As the microwave energy at a fre-
quency of 2450 Megahertz enters the food, the molecules align
themselves with the energy. Because the microwaves are
changing polarity every half cycle, the food molecules are
changing direction every half cycle or oscillating back and
forth 4,900,000,000 times per second. This high speed oscil-
lation causes friction between the molecules, thereby convert-
ing the microwave energy to heat.
SPECIFICATIONS
ITEMS
Power requirements
DESCRIPTIONS
240v
50Hz
Single phase, 3 wire earthed
Power consumption
Microwave output power
Case dimensions
Width
Height
Depth
Cooking cavity dimensions
Width
Height
Depth
Turntable diameter
Control complement
1.4kW
700W (2 litre water load)
622mm
382mm
476mm
406mm
248mm
422mm
395mm
Clock (l:OO- 12:59)
Minute Timer (0- 99 minutes 99 seconds)
Variable Cooking Mode Selector
Repetition Rate:
HIGH .........................Full power throughout the cooking time
MED HIGH .................24 sec. ON, 8 sec. OFF, approx. 70% of full power
MED .......................... 18 sec. ON, 14 sec. OFF, approx. 50% of full power
MED LOW
DEFROST ...................12 sec. ON, 20 sec. OFF, approx. 30% of full power
LOW ..........................6 sec. ON, 26 sec. OFF, approx. 10% of full power
Auto Start Cooking
Instant Cooking
Compu. Defrost Cooking
Reheat Sensor Cooking
Weight Approx. 27kg
2

R-9370
OPERATING INSTRUCTIONS
OPERATION OF AUTO-TOUCH” CONTROL
PANEL
Your new Auto-Touch microwave oven uses a microprocessor, the electronic brain that provides the
wide variety of cooking programmes which could not be achieved by conventional control methods. The
operation of the oven is controlled by touching the appropriate pads arranged on the surface of the con-
trol panel. The lighted digital readout will display the cooking time, Sensor Cook, or Compu Defrost set- I
ting or time:of day or minute timer. Indicators show the variable cooking setting and cooking function
you have programmed.
An entry signal tone should be heard each time you touch the control panel to make a correct entry.
If you do not hear this sound,
1) You have not used enough pressure in touching the pad.
2) You have made more entries than the control panel will accept.
3) You have made an incorrect entry. I
In addition to the entry signal tone, an audible signal will sound for approximately 2 seconds at the end
of the cooking cycle.
* Make sure the oven is plugged into a power point. When the oven is plugged in, the display show
[88:581, flashing on and off each second. Touch the STOP/CLEAR pad: [“-?F] will appear.
* You cannot programme the oven if the door is not closed firmly.
* During cooking, the programme cannot be changed until the STOP/CLEAR pad is touched twice.
All functions are locked in to prevent accidental changes.
If food does not seem to be heating properly, check the indicator immediately below the lighted digital
display. Be sure the Variable Cooking Control is on the proper setting.
* If the electrical power supply to your microwave oven should be interrupted, the display will intermit-
tently show 185:88] after the power is reinstated. If this occurs during cooking, the programme will
be erased. The time of day will be also erased. Simply reset the clock for the correct time of day.
Auto-TouchTMControl Panel
I 7 INDICATORS
LIGHTED DIGITAL DISPLAY
CMP”MfOLowMI0“IL” Shows readout of cooking time, cooking instruction or time of day.
7
3
3
9 r
NUMBER PADS
Touch to enter cooking times, clock time or weight of food.
REHEAT SENSOR PAb
Touch to reheat food.
COMPU DEFROST PAD
Touch to select Compu Defrost settings.
VARIABLE COOKING CONTROL PADS
Touch to select microwave power-setting. If not touched, HIGH
is automatically selected.
STOP/CLEAR PAD
Touch to erase during programming.
Touch once to stop operation of oven during cooking; touch twice
to cancel cooking program.
AUTO START/CLOCK PAD
Touch to set clock or auto start time.
START PAD
Touch to start oven.
INSTANT COOK PAD
Touch to cook for 1 minute at HIGH or increase by 1 minute mul-
tiples during variable cooking.
TIMER/HOLD PAD
Touch to set minute timer or HOLD function.
3

R-9370
Reheat Sensor
HOW ONE TOUCH REHEAT SENSOR WORKS
Sharp’s Electronic Sensory Processor is a semi-conductor device that detects the vapor (humidity) emit-
ted from food as it heats. The Sensor adjusts cooking times and variable power for various foods and
quantities. It takes the guesswork out of microwave heating.
HERE’S AN EXAMPLE OF HOW IT WORKS: &cq *‘Cg
,O%&. 0%
f [ SENSOR j kc
1. Broccoli at room temperature. 2. Heat Broccoli. Vapor is emitted 3. Sensor detects vapor and cal-
Vapor is emitted very slowly. rapidly. culates cooking time and vari-
Before You Use REHEAT SENSOR able power.
1. The oven should not be operated on Sensor Reheat immediately after plugging in the unit. Wait 5
minutes before using the Sensor Reheat.
2. The Reheat Sensor is designed to work best for reheating one to two servings of precooked foods.
The Reheat Sensor may not work perfectly with all menus. Please refer to reheat chart for available
menus.
3. Be sure the exterior of the cooking container and the interior of the oven are dry. Wipe off any moisture
with a dry cloth or paper towel.
4. Room temperature should not exceed 35OC.
5. Dense casseroles are difficult to heat with the Reheat Sensor and may be too cool. Stirring the cas-
serole after heating will help to equalize temperatures.
6. If the Reheat Sensor has not detected the vapor of the food after 15 minutes, [E,c,c3,c] and IRE-
-1 will appear in the display and the oven will shut off.
Selecting Foods
1. Reheat Sensor works with foods at normal storage temperature. For example, chicken pieces would
be at refrigerator temperature and canned soup at room temperature.
2. A minimum quantity of a half cup should be heated when using the Reheat Sensor. Smaller quantites
should be heated by time and variable power.
3. Should foods be cooler than desired, simpiy heat an additional minute or two using Instant Cook pad.
4. If a particular food is hotter than desired, consult your cookbook or cooking guide and choose time
and variable power the next time the food is heated.
5. The arrangement of foods will affect heating results. Place the thickest parts of foods to the outside
of the dish, where they will receive more microwave energy.
6. When possible, stir foods before eating.
Covering Foods
Foods should be covered with plastic wrap or casserole lid when using the Reheat Sensor. Other cover-
ings may cause foods to overheat.
1. Casserole lid.
2. Plastic wraps.
Use plastic wraps recommended for microwave cooking.
Cover dish loosely; fold excess wrap over side of dish.
Do not create an air tight seal, follow procedure in chart.
Be careful when removing any covering to allow steam to escape away from you.
1. Casserole lid 2. Plastic wrap

R-9370
I I
/ To Use Reheat Sensor 1
To use the Reheat Sensor, open oven door, place food in oven, close door and touch the Reheat Sensor
pad. The REHEAT SENSOR pad must be touched within one minute after closing oven door or touching
the STOP/CLEAR pad.
+ Suppose you want to reheat vegetables.
-Step Procedure Pad Order I
1. Touch REHEAT SENSOR pad. I REHEAT I
I I --
SENSOR 1
Display
SENSOR
ICOOK
and
They will be displayed con-
tinuously.
The oven will start operating. When the food is hot as detected by the reheat sensor, all indicators will
go out and an audible signal will sound. The time of day will reappear on the display.
NOTE: Avoid opening the oven door or touching STOP/CLEAR pad when ml m:--(EISTl is displayed.
If this occurs, -1 and IRE-1 (1 will appear and sensor heating will be interrupt-
ed. To continue heating, touch STOP/CLEAR pad. -1 and (-1 I] indicator will
go out. Select heating time and variable power level. Heating with the Reheat Sensor at this point
may result in overheating.
Reheat Chart
FOOD QUANTITY
soup
Dinner Plate
Casserole
Meat Sauce
Canned Food
Steak
Chops
Sliced Roast Beef
Hamburger Patties
Chicken Pieces
Fried Rice
Hot Dog
Sweet Fruit Pie
1-4 cups
1 serving
200-1ooog
200-800g
200-IOOOg
l-4
l-6
200-5oog
2-6
2-4 pieces
200-1ooog
l-2
1-4 pieces
UTENSIL
Casserole
Plate
I Casserole
Mixing Bowl
1
1 Plate
Mixing Bowl
-
Plate’
I COVER
Lid or Plastic Wrap
Plastic Wrap
Lid or Plastic Wrap
Plastic Wrap
Plastic Wrap
Plastic Wrap
Paper Towel
No
5

R-9370 SERVICING
TROUBLESHOOTING GUIDE
Note: For other Test Procedures, please refer to Service Manual for Base Model R-9360.
PROBLEM POSSIBLE CAUSE TEST PROCEDURE OR
CORRECTION
SENSOR COOKING
Oven is in the sensor cooking con-
dition but RH sensor does not end
stage 1. of cooking cycle, cooking
cycle or does not step cooking
cycle.
RH sensor open and/or short. Procedure K.
Defective control unit. Procedure K.
Open or loose wire connection to the above Check and repair wiring.’
-. components.
TEST PROCEDURES (CONT’D)
PROCEDURE
LETTER COMPONENT TEST
J KEY UNIT TEST
If the Indicator does not respond to touching a key Pad use the following matrix and place a jumper wire
between the proper pin connections with the G (1a-pin) cable disconnected from the control unit.
If the indicator responds and oven goes into operation, the key unit is faulty.
If there is no response, replace the control unit.
.
6

R-9370
TEST PROCEDURES (CONT’D)
PROCEDURE
LETTER COMPONENT TEST
K REHEAT SENSOR TEST
Water Load Cooking Test
Check as follows:
(1) Fill 36 milliliters (1 oz) of tap water initially at 2O+l”C (68°F) in a 100 milliliter measuring cup
(2) Place the container on the edge of turntable tray in the oven cavity.
(3) Close the door, and touch “REHEAT SENSOR” pad.
(4) The oven is in the sensor cooking condition.
(5) Sensor cooking time should be 66+35 seconds.
Checking the Control Unit with Use of Dummy Resistor.
(1) Take the procedures according to the instructions in “Servicing of Touch Control Panel”.
Besides it is needed to connect the parts asshown in Fig. A to the connector (C) to enable checking
of the REHEAT SENSOR.
(2) Check the sensor cook operation proceed as follows:
(2-l) Touch REHEAT SENSOR pad.
(2-2) The control panel is in the sensor cooking operation.
(2-3) After approximately 40 seconds, push plunger of MICRO switch.
This condition is same asjudgement by REHEAT SENSOR.
(2-4) After approximately 3 seconds, cooking operation turns off, an audible signal will sound, and the
display will then revert to the time of day.
If the above is not case, the control unit is probably defective.
If the above is proper, the REHEAT SENSOR is probably defective.
MICRO
SWITCH
Figure A. Sensor Dummy Resistor Circuit

R-9370 TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL
The touch control section consists of the following units as
shown in the block diagram.
(1) Key unit
(2) Control unit
Exchange of signals between each unit is indicated by the ar-
rows in the block diagram. The principal functions of these
units and the signalscommunicated among them are explained
below.
l-l. Key Unit
The key unit is composed of a matrix, signals generated
in the LSI are sent to the key unit through P62, P63,
P70 - P73. When a key pad is touched, a signal is com-
pleted through the key unit and passed back to the LSI
through PlO - P13 to perform the function that was
requested.
l-2. Control Unit
Control unit consists of LSI, Power source circuit, Syn-
chronizing signal circuit, ACL circuit, Buzzer circuit,
Reheat sensor circuit and Indicator circuit.
1) Power Source Circuit
This circuit generates voltage necessary in the control
and indicator circuit, from the AC line voltage. In ad-
dition, the synchronizing signal is available in order to
compose a basic standard time in the clock circuit.
2) 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
the commercial frequency.
3) LSI (IX2412YA)
This LSI controls the reheat sensor signal, key touch
and relay control signal for oven function, and control
of the indicator circuit.
4) ACL
A circuit to generate a signal which resets the LSI to
the initial state when power is supplied.
5) Stop switch
A switch to “tell” the LSI if the door is open or closed.
6) Buzzer
The buzzer is responsive to signals from the LSI to
emit noticing sounds (key touch sound and completion
sound).
7) Relay Circuit
To drive the magnetron, fan motor, turntable motor
and light oven lamp.
8) Reheat Sensor Circuit
This circuit detects moisture of a food which is under
cooking, to allow its automatic cooking.
9) Indicator Circuit
This circuit consists of 6-digits, 13 segments display,
five cooking mode indicators.

R-9370
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