Read Sharp R-652M Service Manual online
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.
Click on the first or last page to see other R-652M service manuals if exist.