LG MH-1355M User Manual (English)

Questions and Answers:

L
Laura BallardJul 31, 2025
Why is my LG MH-1355M Microwave Oven sparking?
- B
  Benjamin EvansJul 31, 2025
  Sparks can occur in your LG Microwave Oven for several reasons: * Using metallic ware that touches the oven wall. Avoid metallic ware, unless specifically allowed in the cookbook. * Using ceramic ware with gold or silver powder trimming. Do not use cookware with metallic trimming. * Food does not turn during cooking. If food or cookware extends beyond the turntable edges, rearrange it to allow turning.
J
Jerry CoxAug 5, 2025
Why is the temperature in my LG Microwave Oven lower or higher than preset?
- P
  Paul RobinsonAug 5, 2025
  If the temperature in your LG Microwave Oven is not as expected, it could be due to: * A defective relay 4 or 2 of the P.C.B. * A defective convection heater element. * A defective thermistor. * A defective circulation motor. * A defective drive mechanism of the circulation fan. Check and repair the drive mechanism. * A defective Solenoid. * A defective air duct assembly. Check and repair the air duct assembly.
J
joshua94Aug 9, 2025
Why won't the oven light turn on when I open the door of my LG MH-1355M Microwave Oven?
- B
  bensongabriellaAug 9, 2025
  If the light in your LG Microwave Oven doesn't turn on when you open the door: * There might be no power in your home. Check the wall outlet. * There could be an open wire in the power cord or wire harness. Replace or repair the wiring. * The oven lamp switch may be defective or out of adjustment. * The oven light itself might be defective and need replacement. * There might be an open or loose wire connection to the components. Check the wiring. * The fuse or oven light may be blown.
E
elizabethvegaAug 14, 2025
Why doesn't the oven light turn on during the cook cycle in my LG MH-1355M Microwave Oven?
- D
  Desiree CookAug 14, 2025
  If the oven light doesn't turn on during the cook cycle in your LG Microwave Oven, it could be due to: * A defective relay 3 of the P.C.B.
J
jluceroAug 20, 2025
Why does the turntable motor operate normally but circulation motor does not operate in my LG MH-1355M?
- F
  fosterstephanieAug 20, 2025
  If the turntable motor works but the circulation motor doesn't in your LG Microwave Oven: * Relay 4 of the P.C.B. may be defective. * The circulation motor itself could be defective. * There might be open or loose wiring to the circulation motor. Check and repair the wiring.
R
Ryan AndersonAug 25, 2025
What to do if ":0" does not appear in display window when power cord is first plugged into wall outlet of my LG MH-1355M Microwave Oven?
- T
  Theresa MillerAug 25, 2025
  If ":0" does not appear in the display when you first plug in your LG Microwave Oven: * Ensure the microwave oven plug is fully and securely inserted into the wall outlet.

LG MH-1355M Specifications

General

Type	Microwave Oven
Power Output	900 W
Control Type	Electronic
Turntable	Yes
Cooking Levels	5

Summary

Safety Precautions for Microwave Oven Service

Microwave Oven Specifications

General Cautions and Microwave Radiation

Microwave Radiation Precautions

Precautions regarding exposure to microwave energy during operation or use.

Microwave Oven Installation Guidelines

Earthing Instructions for Safety

Proper grounding procedures for the microwave oven to ensure safety and compliance.

Microwave Oven Feature Diagram

Control Panel Overview and Functions

How the Microwave/Convection Oven Works

Microwave Cooking Explanation

Explanation of how food is cooked using only microwave energy.

Convection Cooking Explanation

Explanation of cooking with hot air circulated by a fan.

Combination Cooking Explanation

Explanation of cooking using both microwave energy and hot air.

Operating Instructions for Microwave Oven

Setting the Time of Day

Step-by-step guide for setting the current time on the oven display.

Using the Regular Timer

Instructions for using the oven as a simple timer without cooking functions.

Micro Time Cooking Procedure

Guide for setting microwave cooking time and power levels.

Convection Cooking Procedure

Instructions for preheating and cooking using convection mode.

Microwave Oven Schematic Diagrams

System 1: Stand-by Condition Schematic

Diagram illustrating the oven's electrical state when idle and powered.

Circuit Description for Oven Operation

Magnetron Tube Function and Testing

Testing the Magnetron Tube

Procedure for testing the magnetron using an ohmmeter for continuity and resistance.

Description and Function of Oven Components

Major Mechanical Components

Description of key mechanical parts like motors, door mechanisms, and heating elements.

Safety and Control Components

Explanation of safety switches, thermostats, and control elements.

Lighting Components

Description of the oven lamp and its switch.

Convection Cooking System and Chamber Assembly

Chamber Assembly Details

Describes the oven cavity's airflow path for convection cooking.

Damper Operation Control

Explains how the damper controls airflow for different cooking modes.

Necessary Tools and Measuring Instruments

Installation and Adjustment of Interlock System

Interlock System Installation Procedure

Steps for installing interlock switches.

Interlock System Adjustment Procedure

Steps for adjusting interlock switches to prevent microwave leakage.

Interlock Continuity Test Procedures

Primary Interlock Switch Continuity Test

Procedure for testing the continuity of the primary interlock switch.

Secondary Interlock Switch Continuity Test

Procedure for testing the continuity of the secondary interlock switch.

Monitor Switch Continuity Test

Procedure for testing the continuity of the monitor switch.

Disassembly and Parts Replacement Procedures

Removing Outer Case

Steps to remove the external casing of the microwave oven.

Removing Control Panel and PCB Assembly

Procedure for removing the control panel and printed circuit board.

Removing Door Assembly

Steps for disassembling and removing the oven door.

Component Removal Procedures (Magnetron, Fan, HV)

Removing Magnetron

Procedure for removing the magnetron component.

Removing Cooling Fan Motor

Steps to remove the cooling fan motor.

Removing High Voltage Diode and Capacitor

Procedure for removing the high voltage diode and capacitor.

Component Removal Procedures (Transformer, Turntable Motor)

Removing High Voltage Transformer

Steps to remove the high voltage transformer.

Removing Turntable Motor

Procedure for removing the turntable motor.

Component Removal Procedures (Circulation Motor, Heater, Switches)

Removing Circulation Motor

Steps to remove the circulation motor.

Removing Convection Heater and Thermistor

Procedure for removing the convection heater and thermistor.

Removing Primary Interlock Switch

Steps for removing the primary interlock switch.

Removing Secondary, Monitor, and Lamp Switches

Procedure for removing secondary interlock, monitor, and lamp switches.

Troubleshooting Oven Off Conditions

Troubleshooting Off Conditions

Troubleshooting steps for issues occurring when the oven is not in a cooking cycle.

Troubleshooting Oven Cooking Conditions

Troubleshooting Cooking Conditions

Troubleshooting for problems during the cooking cycle, like light or motor issues.

Troubleshooting Input and Display Issues

Troubleshooting Input/Display Issues

Troubleshooting for problems related to programming inputs or display readings.

Troubleshooting Microwave Operation Issues

Microwave Power, Sparking, and Uneven Cooking

Troubleshooting for microwave operation faults like low power or uneven cooking.

Troubleshooting Microwave Oscillation and Power

Microwave Oscillation and Power Level Issues

Troubleshooting for no microwave oscillation or incorrect power output.

Troubleshooting Convection Operation Issues

Convection Indicator, Temperature, and Airflow Issues

Troubleshooting for convection mode faults like indicator lights, temperature, or airflow problems.

Component Test Procedures: HV Transformer and Magnetron

Testing High Voltage Transformer and Magnetron

Procedures for testing the high voltage transformer and magnetron resistance.

Component Test Procedures: HV Capacitor and Diode

Testing High Voltage Capacitor and Diode

Procedures for testing the high voltage capacitor and diode continuity.

Component Test Procedures: Switches, Motors, and Fan

Testing Oven Lamp Switch, Motors, and Fan

Procedures for testing oven lamp switch, fan, turntable, and circulation motors.

LG MH-1355M User Manual

Table of Contents