20 Most Recent LG LMVM2277ST Microwave Oven Questions & Answers

"Locked" meaning the buttons don't work/non-responsive (Child Safety Locked)? To Unlock/Disengage the Child Safety. Push and hold the "Clear/Off" button for 3 to 4 seconds. The Child Safety is disengaged - problem solved.

LG LMVM2277ST... | Answered on Jan 28, 2014

All electronics that have relays have a problem with the relays arcing shut. Hit the back of the relay firmly to release it.

LG LMVM2277ST... | Answered on Nov 28, 2013

microwaves are really not cost efficient to repair. It's cheaper to buy a new one. Sears has comparable to your model starting at $70, walmart $60. :)

LG LMVM2277ST... | Answered on Feb 27, 2012

Yes it does control the fans on the microwave oven to turn on and off whenever the heat gets past a certain point. The heat may not be coming from the range top itself though. From what I have seen, the majority of the microwaves mounted above range tops usually have some sort of light source right under them (sometimes built into them) in order to see the stove. The light under them seems to bring a lot of heat that pools in that area. Does your microwave have a light under it? Even if it doesn't have a light mounted under it, heat will pool under an over hang very easily. Desks that have a hutch attachment and a computer or monitor on the desktop have the same sort of problems with heat. If you put your hand above your computer monitor, even with it turned off you might be surprised at how much heat stays there and how long it takes to get rid of it. I think the fans are doing their job in this case.

LG LMVM2277ST... | Answered on Jun 09, 2011

I would say it's the fuse. It's a special ceramic fuse and should be visible if you remove the oven cover,

LG LMVM2277ST... | Answered on May 13, 2011

Sorry to read about your problem, I hope this helps you out.

Display: This is used to show the time, cook time and options you chose during you use.
Cook: Use this feature to cook fresh vegetable, frozen vegetables, rice and cassroles.
Enter/Start: This is used to start and enter any option you choice while operating the unit.
Stop/Clear: Use this function to clear or stop the unit during cooking or choosing a feature.
Reheat: This is use to reheat dinner plates and left overs. Be sure that you do not use any plastic foam or metal plates/utensils this can cause damage to the unit and may cause injury.
Auto Defrost: This is used to defrost food by weight and type. EX: If you have 1 pound of chicken, meat or fish press in the food code by using 1,2,3 and then the weight in pounds (1 pound would be 1.0 enter.)
Quick Frost: This is use with the Rapid defrosting method for 1.0 pound frozen food. If you have a pound of meat, chicken or fish press Quick Frost and it will defrost for that weight only.
Cook Time: This is to set the cook time for the food you are trying to heat or cook. Enter the time you wish to cook and press enter/start (EX: 7mins and 30 secs = 730/start.)
Clock: This is used to set the time of day. Press Clock the the time of day it is and clock again (EX: 11:00 would be 1100 then clock.)
Number: This is the key pad used to enter the cook time, clock or power level.
More: This feature is to add time to the cooking time only in ten second intervals. If you want to add time without restarting press this button to add ten seconds each time it is pressed.
Less: This is used to decrease the cooking time by ten second intervals. If you want to decrease time without restarting the time press this to decrease cooking time in ten second intervals.

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Power Level: This is use to choose the power level in which to cook or heat food or beverages. To change the default setting of 100%, press the power level button and press the level you desire, if you desire only 50% then press power level the 5 and enter/start. Hint: Change the Power level before entering the time your setting to cook
EZ-ON: This is to quickly start the power level to 100%.
Vent High/Low/Off: This is to turn the vent located on the outside of the unit during use. You have the option of turning it off, on, high or low.
Light High/Low/Off: This controls the light on the bottom of the unit if you have a mounted range above your stove or under your top counter cabinets.
Hot Water: This is used to heat water for beverages such as coffee and hot chocolate. Use Extreme caution when removing baverages from your unit, they will be hot and could cause injury.
Popcorn: This is used to pop popping corn, when placing the popcorn in the microwave press the this feature and enter/start and it will automatically start the correct time for cooking. This feature is designed for the individual packaged popcorn use. Do not place any foil or loose popcorn in the unit this could cause damage or injury.
Kids Meals: This is used to REHEAT meals for children it works at a lower power level. This can be used to reheat hot dogs, oatmeal, baby food and soup. Do Not place any metal objects or objects than can melt this can cause damage or injury.
Warm Hold: This is to keep foods or drinks warm for any length of time up to 99 minutes and 99 seconds. Although it is not a recommended to run a unit at the maxium time limit.
Melt: This is used to melt butter, margarine, chocolate, cheese and marshmallows. Do not leave these items unattended during the duration of melting time to prevent any unwanted over heating.
Soften: This is used to soften ice cream, butter, cream cheese, and frozen drinks. Do not place anything in a container that is made of foam or metal this can cause damge or injury.
*Child Lock: If your model has this feature it is used to lock the unit to keep a child from pressing buttons or causing injury.
Open: This is the handle or button on the front of the unit to open the unit after the unit is done cooking or in use. Do not open the door during the use, always press the Stop/Clear button first. Also do not remove hot items without oven mits or waiting time food is at a safe handling temperature.

LG LMVM2277ST... | Answered on Jan 03, 2011


After reading your issue the only option is to replace the keypad so that this issue is solved. Hope this helps...please post back for further assistance.


LG LMVM2277ST... | Answered on Dec 05, 2010

The hum you're hearing is mechanical. There is a large transformer that provides the voltages for the magnetron tube, and it's normal for a transformer to hum to some degree. It's because of how they are built, caused by vibration of the iron pieces used in the transformer core. Glue is used in their construction to help deaden the hum, and over time it can lose its effectiveness and the hum is more noticeable.

The magnetron has a large has a large initial current draw when it first comes on, and the transformer has to work harder which can make the hum louder. Then the current drops and the hum decreases. Some brands (Sharp, particularly) had hums so loud that the transformers required replacement. As long as the oven appears to operating normally otherwise, keep on using it. It's annoying but not hurting anything.

It is possible that the hum is louder in general because the magnetron is just working harder. As it ages, a magnetron's power drops and it draws more current to keep going. This makes the hum louder. Two years may be rather soon, but if the oven's seen lots of use that might be part of the trouble. Again, as long as the thing is cooking, keep using it. Sooner or later the magnetron will go bad and the hum will be obnoxiously loud. That is, it will be if the magnetron shorts out when it goes bad; it can also open circuit, which will cause the hum to drop off and there will be no heating.

I hope this clears things up. Thanks for using FIxya!

LG LMVM2277ST... | Answered on Dec 03, 2010


Does your microwave still heats, while making the humming sound? Investigate these three areas if your microwave won't heat but you hear a loud buzzing or humming noise:

Power Diode

A diode is an electronic component that readily passes current in one direction only and blocks the flow of current in the opposing direction. If your microwave's diode has become defective, your microwave will not heat and you will hear a buzzing noise. Test the diode to determine if this is the cause of your problem. Replace it if it is defective.

Testing a diode

NOTE: Before you test your diode, make sure your microwave is unplugged, and that you discharge the microwave's capacitor.

Whether it is shorted or open, a defective diode will most likely show some sign of defect. Defective diodes will usually emit an electrical burning smell, signifying its defectiveness. Also, it may have split in two, or it may exhibit a burned crack, or possibly even a blistered spot.

A shorted diode is indicated by a loud humming noise from the high voltage transformer, and no heat produced when a cook cycle is initiated. Whereas little or no heat produced in your microwave, with an absence of a humming noise is indicative of an open diode. In either case, the diode has to be replaced.

With your microwave unplugged, and your capacitor discharged, use extreme caution to remove the lead that leads to the capacitor. You can leave the ground connection attached. The side of the diode that goes to the ground is usually marked with a dot, stripe, or arrow. Set your ohmmeter to R x 10,000 or higher. Touch the positive meter probe to the anode and the negative meter probe to the cathode to measure the resistance across the diode terminals. Remember that the cathode is on the side that goes to the ground, which is often marked by a dot, stripe, or an arrow.

A normal diode, that is a non-defective diode, will read anywhere from 50,000 to 200,000 ohms. Differences in microwave make and model account for this large range in resistance readings.

Reverse the meter probes and measure resistance while touching the positive probe to the cathode and the negative probe to the anode. Reversing the probes like this should result in a reading of infinity. Unless a bleeder resistor is present. The presence of a bleeder resistor would produce a reading of the value of the resistor.

High Voltage Capacitor

A capacitor is an electrical device which stores electricity. A defective capacitor may be why your microwave is not heating but you are hearing a buzzing or humming noise. The capacitor will have to be tested to determine if this is the cause of your problem. A defective capacitor will have to be replaced before your microwave will work again. Make sure you discharge the capacitor before you test it, though.


A defective magnetron is the third possible cause of why your microwave is not heating, but you can hear a buzzing noise. Test your microwave's magnetron. Replace it if it is defective.

Testing a magnetron

NOTE: Before you test this component, make sure your microwave is unplugged, and that you have discharged the capacitor.

There are two tests to conduct in order to determine whether or not a magnetron has become defective. If you receive results other than what are detailed below, you will have to replace your microwave's magnetron. Each test is described for you here:

TEST 1: Locate your magnetron and label each of the wires attached to it so that you know which wires are to be replaced where. Set your ohmmeter to the lowest resistance scale. Take a resistance measurement between each of the magnetron's terminals by touching each probe to one terminal each. Reverse the probes and take a second resistance measurement. Each measurement should read less than one ohm.

TEST 2: Set your ohmmeter to its highest resistance scale. Touch one of the meter's probes to a magnetron terminal. Touch the other probe to the metal magnetron housing. Take special caution to not touch the two probes together. This could result in an inaccurate reading. This test should produce a reading of infinity - indicating an open circuit.

Read the tips on the below links on how to replace your microwave oven's diode ad how to discharge the capacitor.



I hope the above is helpful.

Good luck.

LG LMVM2277ST... | Answered on Dec 02, 2010

You dont.
You can use spacers(nonmetalic of course) to raise the platter high enough to disenguage the drive. You can also shift the tray to one side on some models.

LG LMVM2277ST... | Answered on Jan 26, 2009

The fuse is located inside.

LG Microwave... | Answered on Jan 06, 2021

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