Sharp R-290H, Руководство по обслуживанию

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R-290H(S)
12
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
c) Only one indicator does not light up.
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.
N RELAY TEST
L KEY UNIT TEST
1. CARRY OUT 3D CHECKS.
2. Isolate the key unit with the control panel frame to be tested.
3. Using an ohmmeter and referring to the key unit matrix indicated on the control unit circuit, check
the circuit between the pins of the key unit that correspond to the STOP/CLEAR pad. When the
pad is pressed, the ohmmeter should indicate short circuit. When the pad is released, the
ohmmeter should indicate open circuit. If incorrect readings are obtained, the key unit is faulty and
must be replaced. About the other pads, the above method may be used.
4. CARRY OUT 4R CHECKS.
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin No. 3 of the 2 pin connector (A) and normal
open terminal of the relay (RY2) on the control unit with an A.C. voltmeter.
The meter should indicate 230-240 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.
RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS
RY1 Approx. 14.0V D.C. Oven lamp / Turntable motor / Cooling fan motor
RY2 Approx. 12.5V D.C. Power transformer
CARRY OUT 4R CHECKS.
1
2
3
4 5
6
7
8 9
0
POWER
LEVEL
INSTANT
COOK
START
JACKET
POTATO
FROZEN
VEGETABLES
BEVERAGE
FRESH
VEGETABLES
TIMER
CLOCK
EASY
DEFROST
DINNER
PLATE
EXPRESS
DEFROST
RICE PASTA
G 1 G 2 G 3 G 4 G 5 G 6
G 7
G 8
G 9
G10
STOP
CLEAR
Pin
NO. G1 Pin
NO. G10
Key unit ribbon cable
Key unit (Membrane Switch) front view