Sharp R-4H54 User manual

SHARP SERVICE MANUAL
S8207R4H54PJZ
MODEL
MICROWAVE OVEN
R-4H54
In interests of user-safety the oven should be restored to its original
condition and only manufacturer original spare parts must be used.
(RD16101 U)
This is a supplemental Service Manual for Model R-4H54.
This model is quite similar to Base Model R-4A53 (Refer No. is S7106R4A53PJZ).
Use this supplemental manual together with the Base Model Service Manual.
Refer to the Base Model Service Manual for complete operation, service information, etc. (RD17:Ol UI
TABLE OF CONTENTS
GENERAL IMPORTANT INFORMATION Page
......................................................................................................
CAUTION, MICROWAVE RADlATlON,WARNING 1
PRODUCT SPECIFICATIONS ...................................................................................... 1
APPEARANCE VIEW .........................................................................................................................
.....
OPERATION SEQUENCE ................................................................................................................................... ;
SERVICING ................................................................................................................................. 4 ........................................................................................................................................................
TEST PROCEDURE 5
...........................................................................................................................................
TOUCH CONTROL ASSEMBLY 6
COMPONENT .................................................................................................................. REPLACEMENT AND ADJUSTMENT PROCEDURE
MICROWAVE MESUREMENT ..................................................... :4
WIRING DIAGRAM ..................................................................................................................... 25
.......................................................................................................................................
PICTORIAL DIAGRAM 26
..................................................................................................................................
CONTROL PANEL CIRCUIT 28 ..
PRINTED WIRING DIAGRAM ....................................................................................................................... 30
PARTS LIST ..................................................................................................................... 31 .................................................................................................................................................... 32
SHARP CORPORATION

R-4H54
SERVICE MANUAL
SHARP
MICROWAVE OVEN
R-4H54
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 and base model manual, so they will
be qualified to render satisfactory customer service.
(RD367 06U)
CAUTION
I I
1 MICROWAVE RADIATION I
Service engineers should not be exposed to the micro-
wave 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 ener-
gized.
(RD36203U)-
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 defect
(C)The door packing is not damaged.
(D)The door is not deformed or warped.
(E) There is not any other visible damage with tt
Servicing and repair work must be carried out
trained service engineers.
ive.
,
le oven. j
only by
All the parts marked I’*,, on parts list are used at voltages
more than 250V. /
I
(RDSlllOu)
SHARP CORPORATION
OSAKA, JAPAN
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(RD37201 U)
1

R-4H54
PRODUCT SPECIFICATIONS
SPECIFICATION
ITEM I
I DESCRIPTION
Power Requirements / 240 Volts(Australia)/230- 240 Volts( New Zealand)
/ 50 Hertz
1 Single phase, 3 wire earthed
Power Consumption / 1400w
Power Output 750 watts nominal of RF microwave energy (AS 2895 1986)
900 watts nominal of RF microwave energy (IEC-705-1988)
@ I Operating frequency of 2450MHz
Case Dimensions Width 550mm
I Height 312mm
Depth 420mm
--Cooking Cavity Dimensions 1 Width 381 mm
Height 211 mm
Depth 411 mm
Turntable diameter 360mm
Control Complement Touch Control System
Clock( I:00 - 12:59 )
Timer (0 - 99 minutes 99 seconds )
/ Microwave Power for Variable Cooking
Repetition Rate;
HIGH ................................. Full power throughout the cooking time
MEDIUM HIGH ..*........*.......,..*................ approx. 70% of Full Power
MEDIUM .................................................. approx. 50% of Full Power
MEDIUM LOW .........*..*.....I....................* approx. 30% of Full Power
I LOW ...*......................................................
/ SENSOR INSTANT ACTION approx. 10% of Full Power
/ SENSOR COOK
1 DEFROST SENSOR
/ WEIGHT ADJUST
j POWER LEVEL
STOP CLEAR
NUMBER pads
MORE, LESS pad
Set Weight
INSTANT COOK/START
1 AUTO START /CLOCK
Approx. 17.0 kg
NOTE: Numbers and letters shown after sentences such as “RD44101 U” are for factory use only.
2

R-4H54
APPEARANCE VIEW
1. Ventilation openings 8. Touch Control Panel
2. Oven lamp
3. Hinges
4. Safety door latches
5. See through door
6. Coupling
7. Door open button
9. Digital readout
10. Waveguide cover
. I I
11. Access cover for oven ramp replacement
12. Power supply cord
13. Menu Label for Sensor Cook
74. Defrost rack
TOUCH CONTROL PANEL
WEIGHT ADJUST PAD 1 (G-JJ-
SENSOR COOK PAD
Press to select 21 popular menus
with absolute humidity sensor.
Press to zero the weight of
your own dishes before
defrosting on DEFROST
SENSOR. pq (q- F;;I;;;;;lF
.
SENSORINSlliNTACTION with weight sensor.
NUMBER PADS
Press to enter cooking times, Fresh Vegetables Frozen Vegetables
clock time or to select the . --
Sensor Cook menus.
POWER LEVEL PAD
Press to select microwave
teasoned Roast 11 Desserts y
l
power setting.
If not pressed, HIGH is auto- t !
F’ 1
matically selected. 12345
6 7 890
STOP/CLEAR PAD
Press to erase during pro-
gramming.
Press once to stop operation
of oven during cooking; press
twice to cancel cooking pro-
gramme.
c_ POWER
\ LEVEL LE:S t&?E
# 1
c 1
SENSOR INSTANT ACTION
PADS
Press once to cook 6 popular
menus.
.MORE&), LESS(r) PADS
Press to increase/decrease the
time in one minute increments
during cooking or to alter the
doneness for the Sensor Instant
Action, Sensor Cook or
Defrost Sensor modes.
AUTO START/CLOCK PAD
Press to set clock or Auto
Start time.
I multiples each time this oad is
pressed during Microwave
cooking.
3

R-4H54
OPERATING SEQUENCE
SENSOR COOKING CONDITION
Using the SENSOR COOK function, the foods are
cooked without figuring time, power level or quantity.
When the oven senses enough steam from the food, it
relays the information to its microprocessor which will
calculate the remaining cooking time and power level
needed for best results.
When the food is cooked, water vapor is developed.
The sensor “senses” the vapor and its resistance in-
creases gradually. When the resistance reaches the
value set according to the menu, supplementary cook-
ing is started.
The time of supplementary cooking is determined by
experiment with each food category and inputted into
the LSI.
An example of how sensor works:
1. Potatoes at room temperature.
Vapor is emitted very slowly.
2. Heat potatoes. Moisture and humidity is emitted
rapidly. You can smell the aroma as it cooks.
3. Sensor detects moisture and humidity and calcu-
lates cooking time and variable power.
Cooking Sequence.
1.
2.
3.
4.
Touch
NOTE.
Select
Touch
SENSOR COOK pad.
The oven should not be operated on SEN-
SOR COOK immediately after plugging in
the unit. Wait five minutes before cooking
on SENSOR COOK.
desired Sensor setting.
START pad.
The coil of shut-off relays( RYI) is energized, the
oven lamp and cooling fan motor are turned on, but
the power transformer is not turned on.
After about 16 seconds, the cook relay( RY2) is en-
ergized. The power transformer is turned on,
microwave energy is produced and first stage is
started. The 16 seconds is the cooling time required
to remove any vapor from the oven cavity and sen-
sor.
NOTE: During this first stage, do not open the door or
touch STOP/CLEAR pad.
5. When the sensor detects the vapor emitted from the
food, the display switches over to the remaining
cooking time and the timer counts down to zero.
At this time, the door may be opened to stir food,
turn it or season, etc.
6. When the timer reaches zero, an audible signal
sounds. The shut-off relay and cook relay are
de-energized and the power transformer, oven
lamp, etc. are turned off.
7. Opening the door or touching the STOP/CLEAR
pad, the time of day will reappear on the display and
the oven will revert to an OFF condition.

R-4H54
SERVICING
WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of producing very high voltage and current, contact with any part
of the high voltage circuit will result in electrocuition.
REMEMBER TO CHECK 3D
1) Disconnect the supply.
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 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 con-
necting lead of the high-voltage rectifier)
against the chassis with the use of an insu-
lated screwdriver.
Sharp recommend that wherever possible
fault-finding is carried out with the supply discon-
nected. 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 power
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 oEhe power transformer.
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.
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 microwave
timer for two (2) minutes. Set the power level to
HIGH and push the START button. 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 con-
nections tothe component being tested.
When all service work is completed, and the oven is fully assembled, the microwave power output should
be checked and a microwave leakaae test carried out.
TROUBLESHOOTING GUIDE
When troubleshooting the microwave oven, it is helpful
to follow the Sequence of Operation in performing the
checks. Many of the possible causes of trouble will
require that a specific test be performed. These tests
are given a procedure letter which will be found in the
“Test Procedure”section.
IMPORTANT: If the oven becomes inoperative be-
cause of a blown fuse (M8A) in the
upper latch switch - lower latch
switch - monitor switch - monitor
resistor circuit, check the lower latch
switch, monitor switch and monitor
resistor
(M8A). before replacing the fuse
(‘RD81101 U)
5

R-4H54
TEST PROCEDURE ABCDEEEEFGHHI I J K L
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:ONDITION PROBLEM
Home fuse blows when power supply cord is
plugged into wall outlet.
OFF FUSE M8A blows when power supply cord is
CONDITION plugged into wall outlet.
“88:88” does not appear in display but power
supply cord is plugged into wall outlet.
Display does not operate properly when
STOP/CLEAR key is touched.
Oven lamp does not light at door opened.
(Display appears.)
Oven does not start when the START key is
touched. (Display appears)
Oven lamp does not start when START pad is
touched. (Display appears.)
?
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Fan motor does not operate. ?
(Display appears.} L c
Turntable motor assembly does not operate. ?
(Display appears.) I L c
ON Oven or any electrical parts does not stop
CONDITION But cooking time is 0 or STOP/CLEAR key
touched c IC
Oven seems to be operatmg but little or no heat -_,
is produced in oven load. (Microwave power level , --~,n 7 ?
is set at HIGH) / L L L 0 c
Oven does not seems to be operating properly
when MEDIUM HIGH, MEDIUM, MEDIUM LOW
or LOW is set. (Oven operates properly at HIGH
and then the STOP/CLEAR pad is touched the 0 z
oven stops.)
Oven goes into cook cycle but shuts down before
end of cooking cycle.
Oven stops as soon as when the START pad is 7 -Y ‘- -Y
touched. L L’ L L
Oven is in sensor cooking condition or one touch
SENSOR reheat cooking condition, but AH sensor does not
COOKING end 1st stage or does not stop cooking or the
CONDITION oven stops soon.

R-4H54
RE = Replace / CK = Check
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7

R-4H54
TEST PROCEDURES
PROCEDURE
LETTER COMPONENT TEST
MICROWAVE OUTPUT POWER (2 LITRE WATER LOAD)
The following test procedure should be carried out with the microwave oven in a fully assembled
condition (with outer case fitted). Microwave output power from the magnetron can be measured
by way of substitution, i.e. it can be measured by using a water load how much it can be absorbed
by the water load. To measure the microwave output power in the microwave oven, the relation
of calorie and watt is used. On the other hand, if the temperature of the water with V(ml) rises
AT (“C) during this microwave heating period, the calorie of the water is V x AT.
The formula is as follows;
P 8330 x AT
= t
, Our condition for the water load is as follows:
/ Room temperature ............................23+2X Power supply Voltage
I ...-.........Rated voltage
Water load ......2000 ml i
Initial temperature .......23 +I “C Heating time ...... 1min. 51 sec.
P = 75 x AT 1
I
Measuring method:
A) Use two 1 litre Pyrex beakers with a diameter of approximately of 12cms.
B) Place 1 litre of 23°C water in each beaker.
C) Mark Tl on the one beaker and mark T2 on the other one. And stir the water and measure the
temperature of water the thermometer and note them. The graduation of the thermometer must
be scaled by 0.1 “C at minimum and an accurate mercury thermometer is recommended.
D) Place the two beakers as touching each other in the centre of the cavity.
E) Set the timer to 1minute and 51 seconds at 100% power (the time required to raise the water
temperature IO degrees C.)
F) The time must be measured with stopwatch or wristwatch.
G) After 1minute and 51 seconds stop the oven by opening the door.
H) Remove the two beakers from the oven and measure the temperature of the water by stirring
the water with the thermometer and noting the readings.
Example
Initial temperature ............*....................*........................................*.... Tl = 23°C T2 = 24°C
Temperature after 1min. 51 sec. ........................................................ Tl = 33°C T2 = 34°C
Temperature difference Cold-Warm ........................................... AT1 = 10°C AT2 = 10°C
Mean temperature rise AT ........ AT = (AT1 +AT2) / 2 = (10°C + IO’C) / 2 = 10°C
Measured output power
The equation is “P= 75 x AT” ................................................... P= 75 x 10°C =
/ 750 Watts
NOTE: The measured output power should be at least +I5 % of the rated output
power.
CAUTION: 1“C CORRESPONDS TO 75 WATTS.
REPEAT MEASUREMENT IF THE POWER IS INSUFFICIENT.
m OC) IT2 OCt Tr2 OC)
Heat up for 1min. 51 sec.
MICROWAVE OUTPUT POWER (1 LITRE WATER LOAD) (RD82A02J)
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 can be measured by using water load how much it can be absorbed by the
water load. To measure the microwave output power in the microwave oven, the relation of cal-
8

R-4H54
TEST PROCEDURES (CONT’D)
PROCEDURE
LETTER COMPONENT TEST
orie and watt is used. When P(W) heating works for t(second), approximately P x t/4.1 87 calorie
is generated. On the other hand, if the temperature of the water with V(ml) rises AT (“C) during
this microwave heating period, the calorie of the water is V x AT.
I
/ The formula is as follows;
I Pxt/4.187=VxAT P(W)=4.187xVxAT/t
/ Our condition for the water load is as follows:
I Room temperature .....................around 20°C Power supply Voltage .-...........Rated voltage
/ Water load ........1000 g Initial temperature .......IO f2”C Heating time ................ 47 sec.
I P=90xAT
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 of 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 5°C.
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 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
heat-up 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 Tl = 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 A T of
(10 f: 2)“C.
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.
I
I
I Initial temperature ..................................................................................................... Tl = 11“C
/
I Temperature after (47 + 2)= 49 sec. .................................................................... T2 = 21 “C
I Temperature difference Cold-Warm ....................................................*............... AT1 = 10°C
Measured output power
The equation is “P= 90 x AT” ................................................... 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.
9

R-4H54
TEST PROCEDURES (CONT’D)
PROCEDURE
LETTER COMPONENT TEST
T2”C
Heat up for 49 sec.
TOUCH 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 cannot be performed with
only a voltmeter and ohmmeter. In this service manual, the touch control panel assembly is di-
vided into two units, Control Unit and Key Unit.
1. Key Unit.
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. Repair the control unit.
2-l 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.
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 problems 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.
d) Proper temperature measurement is not obtained.
RELAY TEST
Remove the outer case and check voltage between Pin Numbers 3 and 5 of the 5-pin connector
(A) on the control unit with an A.C. voltmeter.
The meter should indicate 240 volts, if not check oven circuit.
RYI and RY2 Relay Test
These relays are operated by D.C. voltage.
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking 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 j OPERATIONAL CONNECTED COMPONENTS
I VOLTAGE
RYl / Approx. 24 V.D.C. / Oven lamp/Turntable motor/Cooling fan motor
RY2 1 ADDrOX. 24 V.D.C. - I Power transformer
10

R-4H54
TEST PROCEDURES (CONT’D)
PROCEDURE
LETTER COMPONENT TEST
M 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
primary on the PWB, this foil pattern acts as a fuse. If the foil pattern is open, follow the trou-
bleshooting guide given below for repair.
Problem: POWER ON, indicator does not light up.
ISTEPS j OCCURENCE , CAUSE OR CORRECTION /
i 1 /The rated voltage is not applied to POWER terminal / Check supply voitage and oven main unit. /
I :of CPU connector (CN-A) I
I 2 jThe rated voltage is applied to primary side of power ’ Power transformer or secondary circuit defective. :
t transformer. Check and repair.
i 3 j Only pattern at “a” is broken. / *Insert jumper wire Jl and solder.
/ 4 / Pattern at “a” and “b” are broken. / ‘Insert the coil RCILF2003YAZZ between “c” and
/ I / “d”,
NOTE:* At the time of these repairs, make a visual in-
spection 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.
N WEIGHT SENSOR ASSEMBLY AND IC3(MEMORY) TEST.
After replacing the weight sensor, turntable, control unit, turntable motor, or
IC3, carry out the following procedure in order to calibrate the weight sensor.
If the weinht sensor is not recalibrate. the food may be over or under cooked.
The following procedure should be carried out with microwave oven in a fully assembled condi-
tion (with outer case fitted).
1. Test Method
(1) Place the turnrable on the turntable support plate correctly, and close the door.
(2) Plug the oven into a power point. (“88:88” will appear on the display.)
(3) Press the STOP/CLEAR pad. (Display shows M : ” with sound of buzzer.)
(4) Press the AUTO START/CLOCK pad. (Display shows “ 0” with sound of buzzer.)
(5) Press the DEFROST SENSOR pad. (Display shows M 0~)
(6) Press the POWER LEVEL pad. (Display shows ” On.)
(7) Press the INSTANT COOK/START pad. (Display shows w TEST” with sound of
buzzer.)
(8) Press the “4” of number pads. (Display shows M 4“ with sound of buzzer, and tuntable
and oven lamps come on.)
(9) After 56 seconds, make sure that the display shows “00055 - 00250”11 with sound
of buzzer.
If display shows less than 00055 or more than 00250, weight sensor is defect.
(10) Place the weight 1.3 kg+1 % (water load 1.3 kg+1 %) on the turntable.
(11) Press the “6” of number pads. (Display shows ”
turntable and oven lamps come on.) 6” with sound of buzzer, and
(12) After 56 seconds, make sure that the display shows “00030 - 00200”” with sound
of buzzer.
11

R-4H54
TEST PROCEDURES (CONT’D)
PROCEDURE
LETTER COMPONENT TEST
If display shows less than 00030 or more than 00200, weight sensor is defect.
(13) Disconnect the oven from power supply, and repeat above procedure items 1 to 7
(14) Press the “7” of number pads, and make sure that the display shows “00030 -
00200” I’.
If display shows less than 00030 or more than 00200, lC3 is defect.
(15) Press the STOP/CLEAR pad. (Display shows “” : ” with sound of buzzer.)
(16) impose 1.3 kg load on the defrosting rack and place it in the oven cavity. Touch the
“DEFROST SENSOR” pad. After approx. 56 seconds, time display appears.
2. Acceptance Standard.
(1) Under 1.3 kg load : 32 min 22 sec. +242 sec.
AH SENSOR TEST
Checking the initial sensor cooking condition
(1) The oven should be plugged in at least five minutes before sensor cooking.
(2) Room temperature should not exceed 95”F(35”C).
(3) The unit should not be installed in any area where heat and steam are generated. The unit
should not be installed, for example, next to a conventional surface unit. Refer to the
“INSTALLATION Instructions”.
(4) Exhaust vents are provided on the back of the unit for proper cooling and air flow in the
cavity.To permit adequate ventilation, be sure to install so as not to block these vents.
There should be some space for air circulation.
(5) 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.
(6) The Sensor works with food at normal storage temperature.For example, chicken pieces
would be at refrigerator temperature and canned soup at room temperature.
(7) Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings.
The sensor will detect the vapor given of by the spray and turn off before food is properly
cooked.
(8) After about 41 minutes if the sensor has not detected the vapor of the food, ERROR will
appear and the oven will shut off.
Water load cooking test
Make sure the oven has been plugged in at least five minutes before checking sensor cook op-
eration. The cabinet should be installed and screws tightened.
(1) Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 miliiliter measuring cup.
(2) Place the container on the center of tray in the oven cavity.
(3) Close the door.
(4) Touch SENSOR COOK pad and number pad 1.Now, the oven is in the sensor cooking
condition and SC-l will appear in the display.
(5) Touch Start pad.The oven will operate for the first 16 seconds, without generating micro-
wave energy.
NOTE: ERROR will appear if the door is opend or STOP/CLEAR pad is touched during first
stage of sensor cooking.
(6) After approximately 16 seconds, microwave energy is produced, oven should turn off when
water is boiling (bubling).
If the oven does not turn off, replace the AH sensor or check the control unit, refer to expla-
nation below:
TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT
To determine if the sensor is defective, the simplest method is to replace it with a new re-
placement sensor.
(1) Disconnect oven from power supply and remove outer case.
(2) Discharge the high voltage capacitor.
(3) Remove the AH sensor.
(4) Install the new AH sensor.
(5) Re-install the outer case.
12

R-4H54
TEST PROCEDURES (CONT’D)
PROCEDURE
LETTER COMPONENT TEST
(6) Reconnect the oven to the power supply and check the sensor cook operation proceed as
follows:
6-l. Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.
6-2. Place the container on the center of tray in the oven cavity.
6-3. Close the door.
6-4. Touch SENSOR COOK pad and number 1 pad.
6-5. Touch Start pad. The control panel is in automatic Sensor operation.
6-6. The oven will turn off automatically when the water is boiling (bubling).
If new sensor dose not operate properly, the problem is with the control unit.
CHECKING CONTROL UNIT
(I) Disconnect oven from power supply and remove outer case.
(2) Discharge the high voltage capacitor.
(3) Disconnect the wire leads from the cook relay.
(4) Disconnect the sensor connector that is mounted to lower portion of control panel.
(5) Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.
(6) Reconnect the oven to the power supply and check the sensor cook operation proceed as
follows:
6-l. Touch SENSOR COOK pad and number 1 pad.
6-2. The control panel is in the sensor cooking operation.
6-3. After approximately 20 seconds, push plunger of select switch.
This condition is same as judgement by AH sensor.
6-4. 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 the case, the control unit is probably defective.
If the above is proper, the AH sensor is probably defective.
PLUNGER
To Connector (F)
on Control Unit
NC
NO
F-l -
F-2- ccr
Rl,R2: 22f2 f 1% l/2W
R3 : 10kR + 5% 1/4W
R4: IMR + 5% l/4W
Sensor Dummy Resistor Circuit
13

R-4H54
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.
(1) Key Unit
(2) Control Unit
The principal functions of these units and the 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 through
B2,B3,B5,86,B7,GO and Gl.
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI
through RO-R3 to perform the function that was re-
quested.
Control Unit
Control unit consists of LSI, power source circuit,
synchronizing signal circuit, ACL circuit, buzzer circuit,
temperature measurement circuit, reheat sensor circuit
and indicator circuit.
1)
2)
LSI
This LSI controls the temperature measurement
signal, reheat sensor signal, key strobe signal, relay
driving signal for oven function and indicator sig-
nal. (RD916Al U)
Power Source Circuit
This circuit generates voltage necessary in the
control unit.
Symbol Voltage Application
VC -5.ov LSI (ICI ), ACL circuit
VP -26V Fluorescent display tube : Grid
and anode voltage
VFl 3Vac Filament of fluorescent display
tube
VF2 (VFI to VF2 voltage)
3)
4)
5)
6)
7)
8)
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. (RD918AZU)
ACL Circuit
A circuit to generate a signal which resets the LSI
to the initial state when power is supplied. (RD919A4U)
Buzzer Circuit
The buzzer responds to signals from the LSI to
emit noticing sounds (key touch sound and com-
pletion sound). (RDSlAAl U)
Reheat Sensor Circuit
This circuit detects moisture of a food which is
cooking,to allow its automatic cooking.
Stop Switch
A switch to “tell” the LSI if the door is open or
closed.
Relay Circuit
To drive the magnetron, fan motor, turntable motor
and light the oven lamp.
Indicator Circuit
Indicator element is a Fluorescent Display.
Basically, a Fluorescent Display is a triode having
a cathode, a grid and an anode. Usually, the cath-
ode of a Fluorescent Display is directly heated and
the filament serves as cathode.
The Fluorescent Display has 6-digits, 13-segments
are used for displaying figures.
10)Weight Sensor Circuit
The circuit measures the weight of food by
piezo-electric device.
14

R-4H54
DESCRIPTION OF LSI
LSI( IZA431 DR)
The l/O signals of the LSl(lZA431 DR) are detailed in the following table.
PIN NO. 1 1 SIGNAL / VSS I I/O i IN
Power source voltace: -5V
VC voltage of power source circuit input.
PIN NO. / 2 f SIGNAL j VASS 1 I/O j IN
Reference voltarre inDut terminal.
A reference voltage applied to the A/D converter in the LSI. The reference voltage is generally maintained at -5V.
PIN NO. ! 3 1 SIGNAL ! VREF I I/O 1 IN
Reference voltage input terminal.
A reference voltage applied to the A/D converter in the LSI. Connected to GND.(OV) (RD93GA6U)
PIN NO. j 4 1 SIGNAL 1 A0 I I/O
Terminal to change functions according to the model.
Signal in accordance with the model in operation is applied to set up its function.
IN
(RD93JAl U)
PIN NO. i 5-7 1 SIGNAL / Al-A3 I I/O IN
Heatinq constant compensation terminal. (RD93GA7U)
PIN NO. / 8 1 SIGNAL / A4 I I/O ~ IN
Input signal which communicates the door open/close information to LSI.
Door closed; “H” level signal( OV). / Door opened; “L” level signal( -5V). (RD937A2Uj
PIN NO. 1 9 1 SIGNAL j A5 I l/O j IN
WEIGHT sensor input.
This input is an analog input terminal from the WEIGHT sensor circuit, and connected to the A/D converter built
into the LSI.
PINNO. / 10 1 SIGNAL j A6 I l/O 1 IN
AH sensor input.
This input is an analog inpu? terminal from the AH sensor circuit, and connected to the A/D converter built into the
LSI. (RD936A2U)
PIN NO. j 11 1 SIGNAL j A7 I I/O / IN
Used for initial balancing of the bridge circuit(absolute humidity sensor). This input is an analog input terminal
from the AH sensor circuit, and connected to the A/D converter built into the LSI.
PINNO. / 12 1 SIGNAL i RESET I I/O 1 IN
Auto clear terminal,
Signal is input to reset the LSI to the initial state when power is applied. Set to “L” level the moment power is
applied, at this time the LSI is reset. Thereafter set at “H” level. (RD93MA4U)
PIN NO. 1 13-14
Terminal not used. 1 SIGNAL 1 EO-El I I/O / OUT
15

PIN NO. : 15 1 SIGNAL j INTI I I/O i IN
,
Signal to svnchronize LSI with commercial power source frequency.
This is the basic timing for all real time processing of LSI.
J7-r-IGND
c 20mK. -i---- LI-5V)
PIN NO. i 16 1 SIGNAL j E3 I I/O i OUT
Magnetron Hiah-voltage circuit drivincl signal.
To turn on and off the cook relay(RY2). In HIGH operation, the signals holds “L” level during microwave cooking
and “H” level while not cooking. In other cooking modes (M.HIGH,MED,M.LOW,LOW) the signal turns to “H”
level and “L” level in repetition according to the power level.
VARI-MODE
HIGH
(100% power)
M.HIGH
(approx 70% power)
MED
(approx.5096 power)
M.LOW
(approx.30% power)
LOW
(approx.lO% power)
ON TIME OFF TIME
32sec. Osec
24sec. 8sec.
18sec 14sec.
12sec. 20sec.
Gsec. 26sec.
PIN NO. I 17-21 1 SIGNAL / CO-C4 I I/O / OUT
Used for initial balancing of the bridge circuit(absolute humidity sensor)
PIN NO. 22-23 1 SIGNAL / C5-C6
Used for initial balancing of the bridge circuit (WEIGHT SENSOR). I I/O 1 OUT
PIN NO. 24 1 SIGNAL ; C7 I I/O j OUT
Oven lamp driving signal (Square waveform: 50Hz).
To turn on and off shut-off relay( RYI ). The square waveform voltage is delivered to the relay( RYI ) driving circuit
and relay (RY2) control circuit.
PIN NO. ; 25 1 SIGNAL j HO I I/O i IN
Signal coming from touch key.
When any one of G-l 2 line keys on key matrix is touched, a corresponding signal from B2,B3,85,B6,B7,GO and
Gl will be input onto HO. When no key is touched, the signal is held at “L” level.
PIN NO. / 26 1 SIGNAL / HI I I/O 1IN
Sinnal similar to HO.
When any one of G-l 1 line keys on key matrix is touched, a corresponding signal will be input into HI.
PIN NO. j 27
Signal similar to HO. 1 SIGNAL / H2 I I/O i IN
When any one of G-IO line keys on key matrix is touched, a corresponding signal will be input into H2.
16

R-4H54
PIN NO. / 28 SIGNAL i H3 I l/O I IN
Sianal similar to HO.
When any one of G-9 line keys on key matrix is touched, a corresponding signal will be input into H3.
PIN NO. / 29 t SIGNAL / H4 I I/O 1 OUT
Digit selection signal.
The relation between digit signal and digit are as follows:
Digit signal Digit
H4 .............................................................. 1st.
H5 ............................................................. 2nd.
H6 3rd. ---------- ----_-GND ..............................*.............*................. H4
H7 - 26V
.................................................*............ 4th.
FO. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..*.........*.**............. 5th. H5 n
BO,Bl ........................................................ 6th. H6 n
Normally, one pulse is output in every 13period, and
input to the Fluorescent Display.
H7 n
FO n
Bl .BO GNG
- 26V
PIN NO. 1 30-32 1 SIGNAL j H5-H7
Digit selection signal. Signal similar to H4. I I/O j OUT
(RD938A2U)
PIN NO. / 33 1 SIGNAL / VPP I I/O 1 IN
Anode (segment) of Fluorescent Displav light-up voltaqe: -26V.
Vp voltage of power source circuit input. (RD93GA8IJ)
PIN NO. 1 34
/ 1 SIGNAL i FO
Diait selection signal. Signal similar to H4. I l/O j OUT
CRD938A2U)
PIN NO. j 35-36 1 SIGNAL / BO-Bl I I/O ; OUT
Dinit selection signal. Signal similar to H4. (RD938A2U)
PIN NO. / 37 1 SIGNAL / 82
Segment data signals.
The relationship between signals and indicators are as follows:
I I/O OUT
Signal Segment Signal
B2 Segment
.................*....*.................... LB GO*.................................a........... f
EE ..........................................UB B7 ............................................. e
............................................. k B6 ............................................. d
:i ...................*.......................... -
..........................................*... ! B5 ............................................. c
~~“““““‘.“‘.““‘.....“““.““.“““’ b
G2 ............................................. h ..................a.......................... a
Gl ............................................. g
Kev strobe siqnal.
Signal applied to touch-key section.
A pulse signal is input to HO-H3 terminal while one of G-l line keys on key matrix is touched.
PIN NO. 1 38
Segment data sianal.
Signal similar to 82.
1 SIGNAL / B3 I I/O / OUT
Kev strobe signal.
Signal applied to touch-key section. A pulse signal is input to HO-H3 terminal
while one of G-2 line keys on key matrix is touched. (RD939A3U)
17

R-4H54
PIN NO. i 39 1 SIGNAL / B4 1 I/O / OUT
Segment data signal. Signal similar to 82.
PIN NO. / 40
Segment data signal.
Signal similar to 82.
1 SIGNAL i B5 I I/O / OUT
Kev strobe signal.
Signal applied to touch-key section. A pulse signal is input to HO-H3 terminal
while one of G-4 line keys on key matrix is touched. (RD939A3U)
PIN NO. 41 1 SIGNAL / B6 1 I/O / OUT
Segment data signal.
Signal similar to B2. Kev strobe siqnal.
Signal applied to touch-key section. A pulse signal is input to HO-H3 terminal
while one of G-5 line keys on key matrix is touched. (RD939A3U)
PIN NO. j 42
Segment data siqnal.
Signal similar to B2.
] SIGNAL j B7 I I/O j OUT
Kev strobe signal.
Signal applied to touch-key section. A pulse signal is input to HO-H3 terminal
while one of G-6 line keys on key matrix is touched. (RD939A3U)
PIN NO. j 43
Segment data signal.
Signal similar to B2.
1 SIGNAL j GO I I/O I OUT
Kev strobe sinnal.
Signal applied to touch-key section. A pulse signal is input to HO-H3 terminal
while one of G-7 line keys on key matrix is touched. (RD939A3U)
PIN NO. : 44
Segment data signal.
Signal similar to 82.
1 SIGNAL / Gl I I/O 1 OUT
Kev strobe signal.
Signal applied to touch-key section. A pulse signal is input to HO-H3 terminal
while one of G-8 line keys on key matrix is touched. (RD939A3U)
PIN NO. ’ 45-49 1 SIGNAL / G2-G6 I I/O OUT
Senment data signal. Signal similar to B2.
PIN NO. ’/ 50
Signal to sound buzzer.
A: Key touch sound.
B: Completion sound.
1 SIGNAL ; G7 I I/O j OUT
0.12 WC.
PIN NO. j 51/52 1 SIGNAL 1 VCC/TEST-f- I/O~~~~~ IN/IN
Connected to GND.
PIN NO. I 53 SIGNAL / 0 OUT I I/O ’ OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of 0 IN.
PIN NO. I
1 54 1 SIGNAL / 0 IN I I/O / IN
Internal clock oscillation frequencv setting input.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit with respect to 0 OUT terminal.
18