Sharp R-652M Service Manual ▷ View online
5
R-652M -
MICROWAVE OUTPUT POWER
The power output of this oven is rated using the method specified by IEC-705. Full details of how to carry out this
procedure can be found in the Sharp Technical Training notes which is available from Sharp Parts Centre
(part number SERV-LITMW01).
procedure can be found in the Sharp Technical Training notes which is available from Sharp Parts Centre
(part number SERV-LITMW01).
The IEC-705 procedure must be carried out using laboratory-type procedures and equipment.
These requirements make the procedure unsuitable for routine performance checks.
Note: The following test method gives an indication of the output power only, it cannot be used to establish the
actual/rated output power. If the true output power is required, then the IEC-705 test method must be used.
Alternative simplified method:
1. Place 2 litres of cold water (between 12
1. Place 2 litres of cold water (between 12
°
C and 20
°
C) in a suitable container.
2. Stir the water and measure the temperature in
°
C. Note temperature as T1.
3. Place the container in the microwave and heat the water for 2 minutes on full power.
4. When the 2 minutes is completed, remove the container and stir the water. Note the water temperature as T2.
5. Calculate the output power using the following formula:
4. When the 2 minutes is completed, remove the container and stir the water. Note the water temperature as T2.
5. Calculate the output power using the following formula:
R.F. Power Output = (T2 - T1) x 70.
Note: The result from this test should be within the allowance of 2000cc alternative method. (+-10%).
MICROWAVE LEAKAGE TEST
This oven should be tested for microwave leakage on completion of any repair or adjustment, following the proce-
dure described in the Sharp Technical Training notes (part number SERV-LITMW01). The maximum leakage
permitted in BS EN 60335-2-25 is 50W/m
dure described in the Sharp Technical Training notes (part number SERV-LITMW01). The maximum leakage
permitted in BS EN 60335-2-25 is 50W/m
2
(equivalent to 5mW/cm
2
), however it is not normal to detect any signifi-
cant leakage, therefore, any leakage which is detected should be investigated.
It is essential that only leakage detectors with current calibration traceable to the National Physical Laboratories are
used.
Suitable leakage detectors :
CELTEC A100
APOLLO X1
APOLLO X1
OUTPUT POWER TEST PROCEDURE
6
R-652M -
TEST PROCEDURES
A
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 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 unit replacement is described according to the symptoms indicated.
1. Key Unit
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 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 unit replacement is described according to the symptoms indicated.
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.
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 Unit
The following symptoms indicate a defective control unit. Replacing the control unit.
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.
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.
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.
b) Clock does not operate properly.
c) Cooking is not possible.
PROCEDURE
LETTER
COMPONENT TEST
C
KEY UNIT TEST
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon
cable is making 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, disconnect 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 STOP/CLEAR pad making 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.
cable is making 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, disconnect 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 STOP/CLEAR pad making 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.
1 min.
RICE /
PASTA
CHICKEN
PORTIONS
FRESH
FISH
CANNED
FOOD
DUAL
GRILL
GRILL
KEBABS
FRESH
VEG.
JACKET
POTATOES
AUTO
DEFROST
LESS
g • oz
Kg • Lb
Kg / Lb
MORE
AUTO
COOK
OVEN
CHIPS
TIMER
STOP/
CLEAR
10 sec.
10 min.
START
CLOCK
AUTO
MINUTE
CRISPY
CRUMB
FOODS
MICROWAVE
POWER
LEVEL
AUTO
START
G12
G11
G10
G 9
G 1
G 2
G 3
G 4
G 5
G 6
G 7
G 8
B
TACT SWITCH TEST
1.
CARRY OUT 3D CHECKS.
2.
Remove the control unit from the control panel.
3.
By using an ohmmeter, check the tact switch operation.
4.
When the tact switch is not depressed, an ohmmeter should indicate an open circuit. When
the tact switch is depressed, an ohmmeter should indicate a short circuit. If improper
operation is indicated, the tact switch is probably defective and should be checked.
the tact switch is depressed, an ohmmeter should indicate a short circuit. If improper
operation is indicated, the tact switch is probably defective and should be checked.
5.
CARRY OUT 4R CHECKS after test.
7
R-652M -
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
D
RELAY TEST
E
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING
BOARD(PWB) IS OPEN
BOARD(PWB) IS OPEN
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.
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.
CARRY OUT 4R CHECKS.
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
troubleshooting guide given below for repair.
primary 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
CAUSE OR CORRECTION
1
The rated AC voltage is not present at
Check supply voltage and oven power cord.
POWER terminal of CPU connector (CN-A).
2
The rated AC voltage is present at primary
Low voltage transformer or secondary circuit defective.
side of low voltage transformer.
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)
1. CARRY OUT 3D CHECKS.
2. Disconnect the leads from the primary of the high voltage transformer. Make sure that the leads
2. Disconnect the leads from the primary of the high voltage transformer. Make sure that the leads
remain isolated from other oven components and chassis. (Use insulation tape if necessary.)
3. Close the door.
4. Reconnect the supply.
5. Check the voltage between Pin Nos. 1 and 3 of the 3 pin connector (A) on the control unit with
4. Reconnect the supply.
5. Check the voltage between Pin Nos. 1 and 3 of the 3 pin connector (A) on the control unit with
an A.C. voltmeter. The meter should indicate 230-240 volts, if not check oven circuit.
6. RY1, RY2 and RY3 TEST
These are operated by D.C. voltage. Check voltage at the relay coil with a D.C. voltmeter during the
These are operated by D.C. voltage. Check voltage at the relay coil with a D.C. voltmeter during the
microwave cooking operation, grill cooking or dual grill cooking operation.
DC. voltage indicated .............. Defective relay.
DC. voltage not indicated ........ Check diode which is connected to the relay coil. If diode is good,
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
RY1
APPROX. 18.0V D.C.
Oven lamp / Turntable motor / Cooling fan motor
RY2
APPROX. 24.0V D.C.
Grill heating element
RY3
APPROX. 18.0V D.C.
High voltage transformer
3
1
RY1
(J1)
a
b
c
d
VRS1
T1
CN - A
8
R-652M -
TOUCH CONTROL
The touch control section consists of the following
units.
units.
(1) Key Unit
(2) Control Unit (The Control Unit consists of Power
(2) Control Unit (The Control Unit consists of Power
Unit and CPU Unit).
The principal functions of these units and the signals
communicated among them are explained below.
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
P20, P21, P22, P23, P24, P25, P26 and P27.
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI
through P43, P44, P45 and P46 to perform the
function that was requested.
generated in the LSI are sent to the key unit through
P20, P21, P22, P23, P24, P25, P26 and P27.
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI
through P43, P44, P45 and P46 to perform the
function that was requested.
Control Unit
Control unit consists of LSI, ACL circuit, indicator
circuit, power source circuit, relay circuit, buzzer
circuit, synchronizing signal circuit and back light
circuit.
circuit, power source circuit, relay circuit, buzzer
circuit, synchronizing signal circuit and back light
circuit.
1) ACL
This circuit generates a signal which resets the LSI
to the initial state when power is supplied.
to the initial state when power is supplied.
2) Indicator Circuit
This circuit consists of 4-digits, 12-segments and 3
common electrodes using a Liquid Crystal Display.
common electrodes using a Liquid Crystal Display.
3) Power Source Circuit
This circuit generates voltages necessary in the
control unit from the AC line voltage.
In addition, the synchronizing signal is available in
order to compose a basic standard time in the
clock circuit.
control unit from the AC line voltage.
In addition, the synchronizing signal is available in
order to compose a basic standard time in the
clock circuit.
Symbol
Voltage
Application
VC
-5.2V
LSI(IC1)
4) Relay Circuit
A circuit to drive the magnetron, grill heating
element, fan motor, turntable motor and light the
oven lamp.
element, fan motor, turntable motor and light the
oven lamp.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to
emit audible sounds (key touch sound and
completion sound).
emit audible sounds (key touch sound and
completion sound).
6) 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.
in order to compose a basic standard time in the
clock circuit.
It accompanies a very small error because it works
on commercial frequency.
7) Door Sensing Switch (Stop Switch)
A switch to “tell” the LSI if the door is open or
closed.
closed.
8) Back Light Circuit
A circuit to drive the back light (Light emitting
diodes LD1- LD5).
diodes LD1- LD5).
A
B
0.12 sec.
2.4 sec.
H : GND
L : -5V
H : GND
L : -5V
1-2
VL2-VL1
IN
Power source voltage input terminal.
Standard voltage for LCD.
3-6
AN7-AN4
IN
Terminal to change cooking input according to the Model.
By using the A/D converter contained in the LSI, DC voltage in accordance
with the Model in operation is applied to set up its cooking constant.
with the Model in operation is applied to set up its cooking constant.
7-8
P63-P62
OUT
Terminal not used.
9
AN1
IN
To input signal which communicates the door open/close information
to LSI.
to LSI.
Door close "H" level signal (0V). Door open "L" level signal (-5V).
10
P60
OUT
Terminal not used.
11-13
P57-P55
OUT
Terminal not used.
14
CNTR0
OUT
Signal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
Pin No.
Signal
I/O
Description
DESCRIPTION OF LSI
OUTLINE OF TOUCH CONTROL PANEL
LSI(IZA954DR)
The I/O signal of the LSI(IZA954DR) are detailed in the following table.
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