LG MG-5355D Service Manual ▷ View online
K. PCB ASSEMBLY REMOVAL
1) Remove the control panel assembly from the
cavity.
2) Remove screw which holding the PCB ASM (Main)
to the control panel.
3) Disconnect the flat cable from the PCB ASM
(Main) and take off the PCB ASM (Main).
4) Remove the holding screws of PCB ASM (Power)
and take off.
L. INTERLOCK SYSTEM
1) INTERLOCK MECHANISM
The door lock mechanism is a device which has
been specially designed to completely eliminate
microwave activity when the dooor is opened dur-
ing cooking and thus to prevent the danger result-
ing from the microwave leakage.
been specially designed to completely eliminate
microwave activity when the dooor is opened dur-
ing cooking and thus to prevent the danger result-
ing from the microwave leakage.
2) MOUNTING OF THE PRIMARY/MONITOR/ SEC-
ONDARY SWITCH TO THE LATCH BOARD
3) INSTALLATION AND ADJUSTMENT OF THE
LATCH BOARD TO THE OVEN ASSEMBLY
• Mount the latch board to the oven assembly.
• Adjust the latch board in the arrow direction so the
• Adjust the latch board in the arrow direction so the
oven door will not have any play in it when the door
is closed.
is closed.
• Tighten the mounting screw.
• Check for playing in the door by pushing the door
• Check for playing in the door by pushing the door
release button. Door movement should be less than
0.5mm. (1/64inch)
0.5mm. (1/64inch)
Don't push the door release button while making
adjustment. Make sure that the latch moves
smoothly after adjustment are completed and that
the screws are tight. Make sure the primary/ moni-
tor/secondary switch operate proprly by following
the continuity test procedure.
smoothly after adjustment are completed and that
the screws are tight. Make sure the primary/ moni-
tor/secondary switch operate proprly by following
the continuity test procedure.
5-6
Control panel
PCB ASM (power)
PCB ASM
(Main)
PRIMARY
SWITCH
SWITCH
ADJUSTMENT
DIRECTION
DIRECTION
MONITOR
SWITCH
SWITCH
SECONDARY
SWITCH
SWITCH
5-7
A. PRIMARY INTERLOCK SWITCH TEST
When the door button is slowly depressed with the
door closed, an audible "click" should be heard at the
same time or successively at intervals. When the but-
ton is slowly released, 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 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.
door closed, an audible "click" should be heard at the
same time or successively at intervals. When the but-
ton is slowly released, 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 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
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 an open circuit in the door
open condition. When the door is closed, meter
should indicate a closed circuit. When the secondary
switch operation is abnormal, make the necessary
adjustment or replace the switch only with the same
type of switch.
Connect the ohmmeter leads to the common (COM)
and normally open(NO) terminals of the switch. The
meter should indicate an open circuit in the door
open condition. When the door is closed, meter
should indicate a 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 close(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 the same type of switch.
Connect the ohmmeter leads to the common (COM)
and normally close(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 the same type of switch.
Interlock Continuity Test
WARNING: FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION
EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS.
TYPE NO. SZM-V16-FA-63 OR VP-533A- OF FOR PRIMARY SWITCH
TYPE NO. SZM-V16-FA-61 OR VP-531A- OF FOR MONITOR SWITCH
TYPE NO. SZM-V01-FA-33 FOR SECONDARY SWITCH
TYPE NO. SZM-V16-FA-61 OR VP-531A- OF FOR MONITOR SWITCH
TYPE NO. SZM-V01-FA-33 FOR SECONDARY SWITCH
COMPONENTS
TEST PROCEDURE
RESULTS
SWITCHES
(Wire leads removed.)
Check for continuity of the switch
with an Ohm-meter
with an Ohm-meter
NOTE: After checking for the continuity of switches, make sure that they
are correctly connected.
Primary
Switch
Switch
Monitor
Switch
Switch
Secondary
Switch
Switch
Door
Door
open
close
COM
NO
COM
NO
COM
NO
COM
NC
5-8
Component Test Procedure
CAUTIONS
1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE
1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE
OUT 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.
(Multi-meter scale: Rx1)
●
Primary winding
●
Secondary winding
●
Filament winding
2. Measure the resistance.
(Multi-meter scale: Rx1000)
●
Primary winding to ground
●
Filament winding to ground
1. Measure the resistance.
(Multi-meter scale: Rx1)
●
Between filament terminals
2. Measure the resistance.
(Multi-meter scale: Rx1000)
●
Filament to chassis.
Approx: 1.0~2.0
Ω
Approx: 80~100
Ω
Approx: 0
Ω
Normal:
∞
Normal:
∞
Normal: Less than 1
Ω
Normal:
∞
Primary
Terminals
Terminals
Secondary
Terminal
Terminal
Filament
Winding
Terminal
Winding
Terminal
5-9
COMPONENTS
TEST PROCEDURE
RESULTS
HIGH VOLTAGE
CAPACITOR
CAPACITOR
HIGH VOLTAGE
DIODE
DIODE
NOTE:
Some inexpensive
meter may indicate
infinite resistance in
both direction.
Some inexpensive
meter may indicate
infinite resistance in
both direction.
Measure the resistance.
(Multi-meter scale: Rx1000)
(Multi-meter scale: Rx1000)
●
Terminal to terminal.
Measure the resistance.
(Multi-meter scale: Rx1000)
(Multi-meter scale: Rx1000)
●
Terminal to case.
Measure the continuity (Forward).
(Multi-meter scale: Rx10000)
(Multi-meter scale: Rx10000)
Measure the continuity (Reverse).
(Multi-meter scale: Rx10000)
(Multi-meter scale: Rx10000)
Normal: Momentary indi-
cates several ohms, and
then gradually returns to
infinite.
cates several ohms, and
then gradually returns to
infinite.
Normal:
∞
Normal: Continuity.
Abnormal:
∞
Normal:
∞
Abnormal: Continuity.
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.
the correct position and be sure that the gasket is in good condition.
Antenna
Gasket
Filament
Terminals
Terminals
Chassis