Sharp R-211A, Service Manual

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R-211A
11
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
I FUSE M6.3A
CARRY OUT 3D CHECKS.
If the fuse M6.3A is blown when the door is opened, check the 1st latch switch, 2nd latch switch, monitor
switch and monitor resistor.
If the fuse M6.3A is blown by incorrect door switching replace the defective switch(es) and the fuse M6.3A.
If the fuse M6.3A is blown, there is a shorts or grounds in electrical parts or wire harness.
Check them and replace the defective parts or repair the wire harness.
CARRY OUT 4R CHECKS.
CAUTION: Only replace fuse with the correct value replacement.
If incorrect readings are obtained, replace the temperature fuse or thermal cut-out.
An open circuit thermal cut-out (MG) indicates that the magnetron has overheated, this may be due
to resistricted ventilation, cooling fan failure or a fault condition within the magnetron or HV circuit.
An open circuit temperature fuse (OVEN) indicates that the food in the oven cavity may catch fire, this
may be due to overheating produced by improper setting of the cooking time or failure of the control
panel.
H MOTOR WINDING TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two
terminals as described in the table below.
Table: Resistance of Motor
Motors Resistance
Fan motor Approximately 330 ohms
Turntable motor Approximately 12 kohms
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
J TIMER MOTOR (WITH DEFROST-SWITCH) TEST
CARRY OUT 3D CHECKS before any of the following timer tests.
TIMER SWITCH- CONTACTS
Disconnect the leads from terminals described at following table. Connect an ohmmeter across
terminals described at following table.
Advance the timer and check that a short circuit reading is obtained on the meter.
Turn the timer back to the zero (0) position and check that an open circuit reading is obtained on the
meter. If these readings are not obtained then replace the timer.
Disconnecting and checking terminals 1 and 4
TIMER - MOTOR
Disconnect the leads from terminals described at following table. Connect an ohmmeter across the
timer motor winding, terminals are described at following table, and check that a reading of resistance
described at following table is indicated.
If this reading is not obtained then the timer is probably defective and should be replaced.
Disconnecting and checking terminals 1 and 2
Resistance of motor winding approximately 22.8 kohms
CARRY OUT 4R CHECKS after any of the above tests.