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R-205M - 7
TEST PROCEDURES
PROCEDURE
LETTER
A
CONTROL PANEL ASSEMBLY TEST
COMPONENT TEST
The control panel consists of circuits including semiconductors such as LSI, timer motor, etc. Therefore,
unlike conventional microwave ovens, proper maintenance can not be performed with only a voltmeter and
ohmmeter.
In this service manual, the control panel assembly is divided in a control unit and a timer motor, and
troubleshooting by unit replacement is described according to the symptoms indicated.
Control Unit.
unlike conventional microwave ovens, proper maintenance can not be performed with only a voltmeter and
ohmmeter.
In this service manual, the control panel assembly is divided in a control unit and a timer motor, and
troubleshooting by unit replacement is described according to the symptoms indicated.
Control Unit.
The following symptoms indicate a defective control unit.
1. Control unit.
The following symptoms indicate a defective control unit.
a) When rotating the potentiometer, the power level can not be selected.
b) Cooking is not possible.
b) Cooking is not possible.
2. Timer motor
The following symptoms indicate a defective timer motor.
a) The timer motor does not return to "0" automatically.
b) A signal bell does not sound.
c) The oven does not turn off automatically.
d) The oven does not turn off.
b) A signal bell does not sound.
c) The oven does not turn off automatically.
d) The oven does not turn off.
B
RELAY TEST
Do not touch the electrical parts and the printed wiring board to prevent an electric
CAUTION
CAUTION
shock. Because the control unit is " TRANSLESS CIRCUIT " and all electrical parts
are used at A.C. line voltage.
are used at A.C. line voltage.
CARRY OUT 3D CHECKS.
Remove the outer case and check voltage between Pin No. 3 of the 2 pin connector (A) and common
terminal of the relay (RY1) on the control unit with an A.C. voltmeter.
The meter should indicate rated voltage, if not check oven circuit.
Remove the outer case and check voltage between Pin No. 3 of the 2 pin connector (A) and common
terminal of the relay (RY1) on the control unit with an A.C. voltmeter.
The meter should indicate rated voltage, if not check oven circuit.
RY1 Relay Test
This relay is operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
This relay is 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
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. 7.0V D.C.
High voltage transformer
CARRY OUT 4R CHECKS.
C
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING BOARD
(PWB) IS OPEN
(PWB) IS OPEN
To protect the electronic circuits, this model is provided with a fine foil pattern added to the input circuit 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.
CARRY OUT 3D CHECKS.
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.
CARRY OUT 3D CHECKS.
STEPS
OCCURRENCE
CAUSE OR CORRECTION
1
The rated voltage is not applied between Pin
Check supply voltage and oven power cord.
No. 3 of the 2 pin connector (A) and the
common terminal of the relay RY1.
2
Only pattern at "a" is broken.
*Insert jumper wire J1 and solder.
3
Pattern at "a" and "b" are broken.
*Insert the coil RCILF2003YAZZ between "c" and "d".
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