LG MS-2043AL Service Manual ▷ View online
A. PRIMARY INTERLOCK SWITCH TEST
When the door release button is depressed slowly
with the door closed, an audible click should be
heard at the same time or successively at
intervals. When the button is released slowly, the
latches should activate the switches with an
audible click.
If the latches do not activate the switches when
the door is closed, the switches should be a
adjusted in accordance with the adjustment
procedure. Disconnect the wire lead from the
primary switch. Connect the ohmmeter leads to
the common (COM) and normally open (NO)
terminal of the switch. The meter should indicate
an open circuit in the door open condition.
When the door is closed, the meter should
indicate a closed circuit.
When the primary switch operation is abnormal,
make the necessary adjustment or replace the
switch only with the same type of switch.
with the door closed, an audible click should be
heard at the same time or successively at
intervals. When the button is released slowly, the
latches should activate the switches with an
audible click.
If the latches do not activate the switches when
the door is closed, the switches should be a
adjusted in accordance with the adjustment
procedure. Disconnect the wire lead from the
primary switch. Connect the ohmmeter leads to
the common (COM) and normally open (NO)
terminal of the switch. The meter should indicate
an open circuit in the door open condition.
When the door is closed, the meter should
indicate a closed circuit.
When the primary switch operation is abnormal,
make the necessary adjustment or replace the
switch only with the same type of switch.
B. SECONDARY INTERLOCK SWITCH TEST
Disconnect the wire lead from the secondary
switch.
Connect the ohmmeter leads to the common
(COM) and normally open (NO) terminals of the
switch. The meter should indicate a open circuit in
the door open condition. When the door is closed,
meter should indicate an closed circuit. When the
secondary switch operation is abnormal, make the
necessary adjustment or replace the switch only
with the same type of switch.
switch.
Connect the ohmmeter leads to the common
(COM) and normally open (NO) terminals of the
switch. The meter should indicate a open circuit in
the door open condition. When the door is closed,
meter should indicate an closed circuit. When the
secondary switch operation is abnormal, make the
necessary adjustment or replace the switch only
with the same type of switch.
C. MONITOR SWITCH TEST
Disconnect the wire lead from the monitor switch.
Connect the ohmmeter leads to the common
(COM) and normally closed (NC) terminals of the
switch. The meter should indicate closed circuit in
the door open condition. When the door is closed,
meter should indicate an open circuit. When the
monitor switch operation is abnormal, replace with
the same type of switch.
NOTE: After repairing the door or the interlock
system, it is necessary to do this continuity
test before operating the oven.
Connect the ohmmeter leads to the common
(COM) and normally closed (NC) terminals of the
switch. The meter should indicate closed circuit in
the door open condition. When the door is closed,
meter should indicate an open circuit. When the
monitor switch operation is abnormal, replace with
the same type of switch.
NOTE: After repairing the door or the interlock
system, it is necessary to do this continuity
test before operating the oven.
5-7
WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION
EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS.
TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF FOR PRIMARY SWITCH
TYPE NO. SZM-V 16-FA-62 OR VP-532A-OF FOR MONITOR SWITCH
TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF FOR SECONDARY SWITCH
TYPE NO. SZM-V 16-FA-62 OR VP-532A-OF FOR MONITOR SWITCH
TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF FOR SECONDARY SWITCH
COMPONENTS
TEST PROCEDURE
RESULTS
SWITCHES
Check for continuity of the
Door
Door
(Wire leads removed)
switch with an Ohm-meter
open
closed
Primary
Switch
Switch
Monitor
Switch
Switch
NOTE : After checking for the continuity of switches, make sure that are
connected correctly.
NO
COM
NC
COM
NO
COM
INTERLOCK CONTINUITY TEST
Secondary
Switch
Switch
5-8
CAUTIONS
1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE
OUTER CASE FROM THE UNIT. PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH
VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE
HIGH VOLTAGE TRANSFORMER. (SEE PAGE 2-1)
VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE
HIGH VOLTAGE TRANSFORMER. (SEE PAGE 2-1)
2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER
OF WATER IN CONTAINER) IN THE OVEN.
COMPONENTS
TEST PROCEDURE
RESULTS
HIGH VOLTAGE
TRANSFORMER
(Wire leads removed)
TRANSFORMER
(Wire leads removed)
MAGNETRON
(Wire leads removed)
(Wire leads removed)
1. Measure the resistance.
(Ohm-meter scale: Rx1)
• Primary winding
• Secondary winding
• Filament winding
• Primary winding
• Secondary winding
• Filament winding
2. Measure the resistance.
(Ohm-meter scale: Rx1000)
• Primary winding to ground
• Filament winding to ground
• Primary winding to ground
• Filament winding to ground
1. Measure the resistance.
(Ohm-meter scale: Rx1)
• Filament terminal
• Filament terminal
2. Measure the resistance.
(Ohm-meter scale: Rx1000)
• Filament to chassis
• Filament to chassis
Approx.: 1.4 ohm
Approx.: 90 ohm
Less than: 1 ohm
Approx.: 90 ohm
Less than: 1 ohm
Normal: Infinite
Normal: Infinite
Normal: Infinite
Normal: Less than 1 ohm
Normal: Infinite
PRIMARY
TERMINAL
TERMINAL
SECONDARY
TERMINAL
TERMINAL
FILAMENT
WINDING
TERMINAL
WINDING
TERMINAL
COMPONENT TEST PROCEDURE
5-9
COMPONENTS
TEST PROCEDURE
RESULTS
HIGH VOLTAGE
CAPACITOR
CAPACITOR
HIGH VOLTAGE
DIODE
DIODE
NOTE :
Some inexpensive meters
may indicate infinite
resistance in both direction.
Some inexpensive meters
may indicate infinite
resistance in both direction.
Measure the resistance.
(Ohm-meter scale: Rx1000)
• Terminal to terminal.
(Ohm-meter scale: Rx1000)
• Terminal to terminal.
Measure the resistance.
(Ohm-meter scale: Rx1000)
• Terminal to case.
(Ohm-meter scale: Rx1000)
• Terminal to case.
Measure the continuity (Forward).
(Ohm-meter scale: Rx10000)
(Ohm-meter scale: Rx10000)
Measure the continuity (Reverse).
(Ohm-meter scale: Rx10000)
(Ohm-meter scale: Rx10000)
Normal: Momentarily indicates
several ohms, and
then gradually returns
to infinite.
then gradually returns
to infinite.
Normal:
∞
Normal:
∞
Abnormal: Continuity.
Normal: Continuity.
Abnormal:
Abnormal:
∞
NOTE: When testing the magnetron, be sure to install the magnetron gasket
in the correct position and be sure that the gasket is in good condition.
Antenna
Gasket
Chassis
Filament
Terminals
Terminals
5-10
COMPONENTS
TEST PROCEDURE
RESULTS
Disconnect the 7 pin
connector from P.C.B.
(Refer to schemetic diagram)
connector from P.C.B.
(Refer to schemetic diagram)
Check for P.C.B. connector.
Cooking Start OFF
1
3
5
FUSE
THERMAL
CUT-OUT
CUT-OUT
Check for continuity of the fuse with an
multi-meter.
multi-meter.
NOTE: If the fuse is blown, check the primary, the secondary, and the monitor switches,
H.V.D. and H.V.C. before replacing the fuse.
If the fuse is blown by improper switch operation replace the defective switch and the
fuse at the same time. Replace just the fuse if the switches operate normally.
H.V.D. and H.V.C. before replacing the fuse.
If the fuse is blown by improper switch operation replace the defective switch and the
fuse at the same time. Replace just the fuse if the switches operate normally.
Normal Abnormal
0°C~Approx.110°C Approx.110°C
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