Sharp R-3A88, Service Manual

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R-3A88
12
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
COMPONENT TEST
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 troubles 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.
K KEY UNIT TEST
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the flat ribbon is marking
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, disconnecct 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 control panel schematic and place a jumper wire between the pins
that correspond to the STOP/CLEAR pad marking 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 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.
G12
G11
G10
G 9
G 8 G 7 G 6 G 5 G 4 G 3 G 2 G 1
KEY UNIT
5 4 3 2 1
0 9 8 7 6
EASY DEFROST
Sukiyaki
INSTANT
COOK
START
REHEAT
HELP
Mini pizza
SLOW COOK RICE COOK
STEAM MENU
POWER LEVEL
STOP / CLEAR AUTO START
Tom Yum Kung
L RELAY TEST
CARRY OUT 3D CHECKS.
Remove the outer case and check the voltage between Pin Nos. 3 and 5 of the 3 pin connector (A) on the
control unit with an A.C. voltmeter.
The meter should indicate 220 volts, if not check oven circuit.
RY1 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.