TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
I
MOTOR WINDING TEST
CARRY OUT aCHECKS
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 246 R
Turntable motor Approximately 12.5 kR
If incorrect readings are obtained, replace the motor.
CARRY OUT $FJ CHECKS
LIVE TEST FOR MOTOR WINDINGS
CAUTION: THE FOLLOWING PROCEDURE REQUIRES THE OVEN TO BE CONNECTED TO THE
SUPPLY AND SHOULD ONLY BE USED IF THE RELEVANT “COLD” CHECKS FOR
THE MOTOR UNDER TEST ARE INCONCLUSIVE.
1. CARRY OUT 3D CHECKS
2. Disconnect the leads from the primary of the power transformer. Make sure that the leads remain
isolated from other oven components and chassis. (Use insulation tape if necessary.)
3. Connect a voltmeter, set to 25OV AC, across the motor terminals. (Refer to the relevant motor test
procedure or pictorial diagram for the correct terminal numbers.)
4. Arrange the meter in a position where it can be read during the test.
(Do not touch the meter, meter leads or oven circuitry while the oven is active.)
5. Close the oven door.
6. Set the power level to HIGH and set the relevant timer for about three (3) minutes.
7. Note the reading on the meter and carefully observe the motor under test to see if it is turning.
8. CARRY OUT 3D CHECKS
9. Remove test meter leads.
1 O.Reconnect the leads to the primary of the power transformer.
If a reading of the line voltage was obtained (step 7) but the motor was not turning then it is faulty and
should be replaced. If the meter indicated that no supply was present then the wiring to the motor
should be checked for continuity.
J
BLOWN FUSE M8A
CARRY OUT 3D CHECKS
1. If the fuse M8A is blown, there could be shorts or ground in electrical parts or wire harness.
Check them and replace the defective parts or repair the wire harness.
2. If the fuse M8A is blown when the door is opened, check the 1st. latch switch, 2nd. latch switch,
monitor switch.and monitor resistor.
If the fuse M8A is blown by incorrect door switching replace the defective switch(s) and the fuse
M8A.
3.
If the fuse M8A is blown, there could be a short in the asymmetric rectifier or
there could be a ground in wire harness. A short in the asymmetric rectifier may have occured due
to short or ground in H.V. rectifier, magnetron, power transformer or H.V. wire. Check them and re-
place the defective parts or repair the wire harness.
CARRY OUT 4R CHECKS
CAUTION: Only replace fuse M8A with the correct value replacement
15
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