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
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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