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AX1100(R)M
9 – 2
[3] C: HIGH VOLTAGE RECTIFIER TEST
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be tested using an ohmmeter set to its highest range.
Connect the ohmmeter across the terminal B+C of the high voltage rectifier and note the reading obtained. Reverse the meter leads and note this
second reading. The normal resistance is infinite in one direction and more than 100 k
Connect the ohmmeter across the terminal B+C of the high voltage rectifier and note the reading obtained. Reverse the meter leads and note this
second reading. The normal resistance is infinite in one direction and more than 100 k
in the other direction.
CARRY OUT 4R CHECKS.
ASYMMETRIC RECTIFIER TEST
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The asymmetric rectifier can be tested
using an ohmmeter set to its highest range across the terminals A+B of the asymmetric rectifier and
note the reading obtained. Reverse the meter leads and note this second reading. If an open circuit is indicated in both directions then the asymmetric
rectifier is good. If the asymmetric rectifier is shorted in either direction, then the asymmetric rectifier is faulty and must be replaced with high voltage
rectifier. When the asymmetric rectifier is defective, check whether magnetron, high voltage rectifier, high voltage wire or filament winding of the high
voltage transformer is shorted.
using an ohmmeter set to its highest range across the terminals A+B of the asymmetric rectifier and
note the reading obtained. Reverse the meter leads and note this second reading. If an open circuit is indicated in both directions then the asymmetric
rectifier is good. If the asymmetric rectifier is shorted in either direction, then the asymmetric rectifier is faulty and must be replaced with high voltage
rectifier. When the asymmetric rectifier is defective, check whether magnetron, high voltage rectifier, high voltage wire or filament winding of the high
voltage transformer is shorted.
CARRY OUT 4R CHECKS.
NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF THE MEASURING INSTRUMENT MUST HAVE
A VOLTAGE AT LEAST 6 VOLTS, BECAUSE OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIRECTIONS.
[4] D: HIGH VOLTAGE CAPACITOR TEST
CARRY OUT 3D CHECKS.
1. Isolate the high voltage capacitor from the circuit.
2. Continuity check must be carried out with measuring instrument which is set to the highest resistance range.
3. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10M
after it has been charged.
4. A short-circuited capacitor shows continuity all the time.
5. An open capacitor constantly shows a resistance about 10 M
because of its internal 10M resistance.
6. When the internal wire is opened in the high voltage capacitor shows an infinite resistance.
7. The resistance across all the terminals and the chassis must be infinite when the capacitor is normal.
If incorrect reading are obtained, the high voltage capacitor must be replaced.
CARRY OUT 4R CHECKS.
[5] E: SWITCH TEST
CARRY OUT 3D CHECKS.
Isolate the switch to be tested and using an ohmmeter check between the terminals as described in the following table.
If incorrect readings are obtained, make the necessary switch adjustment or replace the switch.
CARRY OUT 4R CHECKS.
[6] F: MONITOR SWITCH TEST
CARRY OUT 3D CHECKS.
Before performing this test, make sure that the monitored interlock switch and the relay RY-4 on the control unit are operating properly, according to
the above Switch Test Procedure. Disconnect the wire lead from the monitor switch (COM) terminal. Check the monitor switch operation by using the
ohmmeter as follows. When the door is open, the meter should indicate a closed circuit. When the monitor switch actuator is pushed by a screw driver
through the right latch hole on the front plate of the oven cavity with the door opened (in this condition the plunger of the monitor switch is pushed in),
the meter should indicate an open circuit. If improper operation is indicated, the switch may be defective. After testing the monitor switch, reconnect
the wire lead to the monitor switch (COM) terminal and check the continuity of the monitor circuit.
the above Switch Test Procedure. Disconnect the wire lead from the monitor switch (COM) terminal. Check the monitor switch operation by using the
ohmmeter as follows. When the door is open, the meter should indicate a closed circuit. When the monitor switch actuator is pushed by a screw driver
through the right latch hole on the front plate of the oven cavity with the door opened (in this condition the plunger of the monitor switch is pushed in),
the meter should indicate an open circuit. If improper operation is indicated, the switch may be defective. After testing the monitor switch, reconnect
the wire lead to the monitor switch (COM) terminal and check the continuity of the monitor circuit.
CARRY OUT 4R CHECKS.
[7] G: THERMISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect the thermistor from the control unit. Measure the resistance of the thermistor with an ohmmeter.
If the meter does not indicate above resistance, replace the thermistor. CARRY OUT 4R CHECKS.
Table: Terminal Connection of Switch
Plunger Operation
Common terminal to Normally open terminal
Common terminal to Normally close terminal
Released
Open circuit
Short circuit
Depressed
Short circuit
Open circuit.
Room Temperature
25
C
100
C
200
C
Resistance
Approximately 200 k
Approximately 10 k
Approximately 1 k
D2
D1
ASYMMETRIC
RECTIFIER
HIGH VOLTAGE
RECTIFIER
A
B
C
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