Page 1 Product Training LMVM2277ST Over-The-Range Microwave Oven LMVM2277ST Pres. V. 1.0 080124...
Page 2 LG supplies this training class for the benefit of all in attendance. We ask your assistance in keeping this a professional meeting and to remain focused only on the technical improvement and education of our service network.
Page 3 Preliminary IMPORTANT SAFETY NOTICE DISCLAIMER MODIFICATIONS ESD ISSUE REGULATORY INFORMATION Slide Number Page in Training Manual LMVM2277ST...
Page 4 Preliminary COMPLIANCE The responsible party for this device’s compliance is: LG Electronics Alabama, Inc. PO Box 240007 Huntsville, AL 35813 LMVM2277ST...
Page 5 Contents Safety Notices and Warnings Contact Information Contents Specifications Safety Notices Serial Number Identification Introduction Controls Installation Accessories Drying Rack LMVM2277ST...
Page 6 Serial Number LMVM2277ST...
Page 7 Serial Number LMVM2277ST...
Page 8 Introduction LMVM2277ST...
Page 9 Headline The LMVM2277ST is part of the new LG complete kitchen suite. LMVM2277ST...
Page 10 Reminder Always run a microwave leak test. If the oven is operational, test it before and after the repair. The Federal standard for leakage is less than 5 mW/cm2, but LG’s standard is less than 1 mW/cm2. LMVM2277ST...
Page 11: Specifications
1,700 W max (MWO + lights + fan) Consumption Microwave Output 1,100 W (IEC 60705) 2,450 MHz ± 50 MHz Frequency Power Supply 120 V , 60Ø Rated Current 14.5 Amps (MWO + lights + fan) Magnetron Cooling Forced Air Cooling LMVM2277ST...
Page 12: Switch Chart
Switch Chart Switch Mode Primary Secondary Monitor Conditions Door Open OPEN OPEN CLOSE Door Closed CLOSE CLOSE OPEN LMVM2277ST...
Page 13: Warranty
WARRANTY LMVM2277ST...
Page 14: Safety And Warnings
When cooking very small amounts of food, put a glass of water in the cooking compartment. • Do not operate the oven on a 2-wire extension cord during repair or use. • Use proper ESD precautions when handling the PCB. LMVM2277ST...
Page 15 Safety and Warnings • Never put anything into the latch holes and interlock switches. • Remove your watch before working on or around the magnetron. • Do not operate the oven without the glass tray / turntable in place. T- 7 LMVM2277ST...
Page 16 Safety and Warnings Be sure the magnetron gasket is properly installed around the dome of the tube whenever installing the magnetron. See magnetron section, page 21. LMVM2277ST...
Page 17 Safety and Warnings Always use a properly wired and grounded 3-wire dedicated outlet to power the oven. (120 VAC, 20 A.) Never cut the ground prong off the plug or otherwise defeat the grounding of this appliance. LMVM2277ST...
Page 18: Installation
Installation The LMVM2277ST must be properly installed before operation. Installation includes mounting the bracket on the wall with toggle bolts and/or lag bolts and drilling holes in the cabinet above the oven to accommodate the electric cord and the upper mounting bolts.
Page 19 The ventilation fan can exhaust air in any of three directions: through the back wall, through the roof, or recirculated through the charcoal filter into the kitchen. If the air is vented through a duct to the outside, the damper and flap must be installed. LMVM2277ST...
Page 20: Turntable Installation
Turntable Installation Round glass tray Rotating ring Rectangular glass tray Turntable drive arm LMVM2277ST...
Page 21 Follow these steps to install the turntable components and to ensure they function correctly. 1. Install the turntable drive arm and position it securely on the drive cam. 2. Install the rectangular glass tray and ensure it slides properly. LMVM2277ST...
Page 22 Turntable Installation 3. Place the rotating ring on top of the rectangular glass tray. 4. Be sure the drive arm can rotate in the hollow area on the bottom of the rectangular tray. LMVM2277ST...
Page 23 There should be rotation on the turntable AND lateral motion involving the rectangular tray. LMVM2277ST...
Page 24: Operating Instructions
Operating Instructions T-10 LMVM2277ST...
Page 25 7, 3, and 0 to set the second cooking time of seven minutes, thirty seconds, then press POWER LEVEL and 7 to set the power level of the second cooking period to 70%, and then press START. T-10 LMVM2277ST...
Page 26 PLEASE SET THE TIME OF DAY. If the time is not set, the colon (:) will display until you touch CLOCK. To set the clock, touch CLOCK, the numbers (0 through 9) to set the time, START, and START again. T-11 LMVM2277ST...
Page 27 To run the fan for a set period, turn it on and set the desired speed, as illustrated above. Then touch AUTO TIME SET several times to increase the time before the fan is turned off. T-10 LMVM2277ST...
Page 28 Operating Instructions To toggle the CHILD LOCK feature ON or OFF, touch and hold the START/CHILD LOCK button for 5 seconds until a beep sounds. T-11 LMVM2277ST...
Page 29 Operating Instructions The EZ-ON button turns the oven on at full power for 30 seconds. To cook for 2 minutes, press it four times. T-11 LMVM2277ST...
Page 30 Operating Instructions To use the timer without operating the oven, press TIMER ON/OFF, the numbers of the time to set, and TIMER ON/OFF. The timer will count down and beep at the end of the set period. T-11 LMVM2277ST...
Page 31: Power Levels
8 sec. 12 sec. 2 sec. 10 sec. 10 sec. 2 sec. 12 sec. 8 sec. 2 sec. 14 sec. 6 sec. 2 sec. 16 sec. 4 sec. 2 sec. 18 sec. 2 sec. 100% magnetron is on T-12 LMVM2277ST...
Page 32: Care And Cleaning
Care and Cleaning Cleaning the oven is easy. Always unplug the oven before cleaning the control panel to avoid touching too many buttons at once and damaging the microprocessor. T-13 LMVM2277ST...
Page 33 Spray the glass cleaner onto the cloth rather than onto the oven. DO NOT USE abrasive cleanser, steel wool, scrubbing pads, gritty washcloths, rough paper towers, and those sorts of things. They can damage the finish on your oven. T-13 LMVM2277ST...
Page 34 This prevents the spatters from being baked onto the oven surfaces during subsequent cooking. Be especially careful to clean the area where the door closes and touches the frame of the oven. LMVM2277ST...
Page 35 The steam will soften soils and allow them to be wiped away with a damp towel. If you cut up a lemon and put it into the water during the cooking, your oven and entire kitchen will be citrusy fresh, T-13 LMVM2277ST...
Page 36: Grease Filters
Clean them by swishing them in hot, soapy water and rinsing them. Shake them to dry them and replace them in their holders. DO NOT OPERATE the oven without the grease filters in place. T-13 LMVM2277ST...
Page 37: Charcoal Filter
6 ~ 12 months. It is not washable and must be replaced. DO NOT OPERATE the oven without the charcoal filter in place, unless, of course, the oven is vented to the outside. The charcoal filter part number is 5230W1A0003A. T-14 LMVM2277ST...
Page 38 Charcoal Filter Remove the two screws at the top of the oven housing. (These are the two middle screws.) If the oven is properly installed, these screws will be accessible in front of the edge of the cabinet. T-14 LMVM2277ST...
Page 39 Charcoal Filter Remove the wire cover. It is a small plastic guide that fits with the vent grille on the left end. It can be pulled out through the top when the door is closed. T-14 LMVM2277ST...
Page 40 Charcoal Filter Open the door and tip the vent grille forward. Lift it out to remove it. T-14 LMVM2277ST...
Page 41 Charcoal Filter Remove the old filter and replace it with a new one. It is not reusable. T-14 LMVM2277ST...
Page 42: Oven Light
Oven Light Push the metal tab of the lampholder off the plastic tab and pull the lamp and holder out. Replace the bulb and reinstall the holder. T-15 LMVM2277ST...
Page 43 Oven Light The lampholder tab rests against a plastic tab on the oven vent housing. It is a simple snap fit. Push it aside to remove or replace the lamp assembly. T-15 LMVM2277ST...
Page 44 Oven Light Lift out the lamp holder, which includes the bulb and the socket, which is attached to the reflector with two bolts. Do not touch the bulb with your fingers. Use a clean, protective cloth or paper towel. T-15 LMVM2277ST...
Page 45 The bulb is not equipped with a filament anchor, so there is no top or bottom. The socket/pigtail is attached to the lamp holder by two bolts. The socket need not be removed to change the bulb. T-15 LMVM2277ST...
Page 46: Disassembly And Repair
Disassembly and Repair T-16 LMVM2277ST...
Page 47: Main Board And Power Board
Main Board and Power Board The main board and power board can be serviced without dismounting the oven. T-16 LMVM2277ST...
Page 48: Main Board
You’ll have to roll it to the right a little bit to make it clear easily. Note: The photo is in the lab, but this can be achieved while the microwave is mounted on the wall. T-16 LMVM2277ST...
Page 49 Main Board This drawing shows the location of the main board (upper item) and the ventilation duct inside the microwave oven case. The latch board is the lower item T-17 LMVM2277ST...
Page 50 Main Board Remove the wires and connectors from the main board. Remove the screws that hold it in the case to change the board. T-17 LMVM2277ST...
Page 51: Outer Case Removal
Outer Case Removal T-18 LMVM2277ST...
Page 52 Remove the two vent grille screws. Remove the four screws securing the oven case to the oven. (Four on the top, one on the right side.) Remove two screws on each side of the base plate. T-18 LMVM2277ST...
Page 53 Outer Case – Removal Remove the four screws holding the outer case to the back of the oven. Lift the outer case carefully from the oven. Store it to prevent damage while you are working on the oven. T-18 LMVM2277ST...
Page 54: Door Interlock Switches
Door Interlock Switches Disconnect the interlock switches. (You’ll need a Torx® T-20T (Tamperproof) bit. T-19 LMVM2277ST...
Page 55 Door Interlock Switches The connectors are keyed to prevent improper connection. It is still a good idea to check the wire colors, especially where there are multiple connectors. T-19 LMVM2277ST...
Page 56 Door Interlock Switches Left side switch T-19 LMVM2277ST...
Page 57 Door Interlock Switches Right side switch T-19 LMVM2277ST...
Page 58 Door Interlock Switches INTERLOCK SWITCH CONTINUITY TEST The door interlock switches should click audibly when the door is opened or closed. If the latches do not activate the switches properly, they can be adjusted T-20 LMVM2277ST...
Page 59 Connect an ohmmeter to the COM (common) and NO (normally open) terminals of the switch. With the door open, the meter should indicate an open circuit. Closing the door should indicate a closed circuit. (See chart, couple of slides later.) T-20 LMVM2277ST...
Page 60 Connect an ohmmeter to the COM (common) and NC (normally closed) terminals of the switch. With the door open, the meter should indicate a closed circuit. Closing the door should indicate an open circuit. (See chart, next slide.) T-20 LMVM2277ST...
Page 61 Door Interlock Switches T-20 LMVM2277ST...
Page 62 PRIMARY Type SZM-V16-FA-63 –or-- VP-533A-OF –or-- V5230Q SECONDARY Type SZM-V16-FA-63 –or-- VP-533A-OF –or-- V5230Q MONITOR Type SZM-V16-FA-62 –or-- VP-532A-OF –or-- V5220Q NOTE! After repairing the door, interlock system, or switches, these continuity tests must be performed. T-20 LMVM2277ST...
Page 63 Magnetron Remove the outer case. Remove the damper bracket. Disconnect the transformer lead wire. Remove the four screws securing the transformer. Remove two screws securing the fan motor. T-21 LMVM2277ST...
Page 64 Magnetron Remove four screws securing the magnetron and lift it out carefully. When removing or replacing the magnetron, ensure the woven metal gasket is undamaged and properly positioned. T-21 LMVM2277ST...
Page 65: Stirrer Fan And Cover
It is held in place by one screw and three tabs. This cover must be in place to operate the microwave oven safely. Remove the screw and pull the cover out of the tabs, being careful not to bend or break the cover. T-21 LMVM2277ST...
Page 66 Stirrer Fan and Cover The stir fan presses onto the shaft. The cover is secured by three tabs and a single screw. T-21 LMVM2277ST...
Page 67: Door Removal
Door Removal Remove the two vent grille mounting screws. Remove the door hinge screws. Remove the wire cover and open the hinge covers T-22 LMVM2277ST...
Page 68 Door Removal Open the door. Remove the vent grille. Disconnect the two flat cables at the face plate connectors. T-22 LMVM2277ST...
Page 69 Door Removal Use a small screwdriver to remove the clip on the end of the pneumatic damper and take the spring out of the oven. USE CAUTION! The damper could expand without notice. T-22 LMVM2277ST...
Page 70 Set it on a protective surface, like a blanket, to prevent scratches or damage. When replacing the door, always check the interlock switches and perform a microwave leakage test. (See page 33 in the training manual.) T-22 LMVM2277ST...
Page 71: Door Disassembly
Door Disassembly Remove the four screws securing the choke cover to the door. Separate them carefully using a small screwdriver or a knife. T-23 LMVM2277ST...
Page 72 Door Disassembly Remove the two screws securing the handle. Remove the door frame. Remove the two screws securing the PCB (Printed Circuit Board.) T-23 LMVM2277ST...
Page 73 Door Disassembly Disconnect the flat plastic connector. (See page 24 in the training manual.) T-23 LMVM2277ST...
Page 74 There should be no play between the inner door surface and the oven frame. If the door is not mounted properly, microwaves may leak between the door and oven or the monitoring and safety switches will prevent usage. T-23 LMVM2277ST...
Page 75 Door Disassembly Always perform a microwave leakage test whenever the door is adjusted or repaired. photo goes here T-23 LMVM2277ST...
Page 76: Flat Plastic Connector
Flat Plastic Connector The flat plastic connector (FPC) is opened and closed by moving the plastic slide at the top to release or secure the flat cable. To release the cable, pull the latch away from the connector. T-23 LMVM2277ST...
Page 77 Flat Plastic Connector Lift the flat cable out. It is held in place by two hooks that fit into the two square holes on the cable. T-23 LMVM2277ST...
Page 78 (away from the connector.) Insert the flat cable and secure the hooks in the two square holes. Press the latch into place and gently tug on the cable to be sure it is secure. T-23 LMVM2277ST...
Page 79: Ventilation Fan Motor
Ventilation Fan Motor If the oven has not been installed, be sure the mounting bracket has been removed from the back of the oven. T-25 LMVM2277ST...
Page 80 Ventilation Fan Motor Remove the two screws securing the blower plate cover. (One on the top and one on the back.) T-25 LMVM2277ST...
Page 81 (front, top, or back) for venting. Replace the screws in the top and back to secure it against vibration. Replace the top plate (unless you are venting the oven through the roof.) Attach the adapter and duct work for venting. T-25 LMVM2277ST...
Page 82: Turntable Motor
Turntable Motor Remove the base. This can be done with the oven mounted on the wall. T-26 LMVM2277ST...
Page 83 Turntable Motor The turntable motor is attached to the base with a tab and a screw. T-26 LMVM2277ST...
Page 84: Humidity Sensor
Humidity Sensor With the outer case removed, remove one screw and lift out the humidity sensor. Unplug the connector at the main board and replace the defective sensor. T-26 LMVM2277ST...
Page 85: Component Test Procedures
Component Test Procedures Test procedures are listed to help the servicer determine which parts are defective by doing as little disassembly as possible. T-27 LMVM2277ST...
Page 86: Transformer Test
Transformer Test T-27 LMVM2277ST...
Page 87 0.2 ~ 1.5 Ω Primary (A & C) – Low (G & GND) 50 ~ 120 Ω Secondary 0.5 ~ 2.0 Ω Filament (E & F) Meter scale Rx1000 Primary to ground Normal = infinity Filament to ground Normal = infinity T-27 LMVM2277ST...
Page 88: Magnetron Test
Magnetron Test T-27 LMVM2277ST...
Page 89 To test the magnetron, remove the connector to take it out of the circuit. Measure the resistance between the following points: Meter scale Rx1 > 1 Ω Filament terminals Meter scale Rx1000 Filament to chassis Normal = infinity T-27 LMVM2277ST...
Page 90: Capacitor Test
Capacitor Test T-28 LMVM2277ST...
Page 91 Remove the wire leads. They may be equipped with press-tab releases. Measure the resistance between the following points: Meter scale Rx1000 Terminal to terminal Normally indicates several ohms, then gradually drifts toward infinity. Terminal to case Normal = infinity T-28 LMVM2277ST...
Page 92 Capacitor Test The capacitor can be serviced while the oven is still mounted. Remove the door. (See page 22.) T-28 LMVM2277ST...
Page 93 Capacitor Test Remove a single screw and take off the cover that covers the capacitor. T-28 LMVM2277ST...
Page 94 Relay Test the relay by removing its connector and measuring the continuity between the terminals. T-29 LMVM2277ST...
Page 95: Fan Motor
Fan Motor T-29 LMVM2277ST...
Page 96 Unplug the fan connector and measure the resistance between the terminals. Terminal A Terminal B Brown Terminal C Yellow 12 ~ 16 Ω A ~ C 9 ~ 23 Ω A ~ B Other readings or infinite resistance indicates a motor failure. T-29 LMVM2277ST...
Page 97: Low Voltage Transformer
Low Voltage Transformer T-29 LMVM2277ST...
Page 98 Low Voltage Transformer Unplug the transformer connector and measure the resistance between the terminals. Terminal A Terminal B Black Terminal C White 18 ~ 30 Ω A ~ C 18 ~ 30 Ω A ~ B T-29 LMVM2277ST...
Page 99: High Voltage Diode
High Voltage Diode Measure the continuity in both directions using meter scale Rx1000. Forward: Normal = continuity Defective = infinity Reverse: Normal = infinity Defective = continuity T-30 LMVM2277ST...
Page 100 High Voltage Diode T-30 LMVM2277ST...
Page 101 High Voltage Diode This photo shows the diode connected with +9 VDC applied to the cathode. The meter reads 0.00 VDC because the diode is blocking the flow. T-30 LMVM2277ST...
Page 102 High Voltage Diode This photo shows the diode’s forward bias with +9 VDC connected to the anode. T-30 LMVM2277ST...
Page 103 Turntable Motor Remove the connector and measure the resistance across the terminals using meter scale Rx1000. Normal = 2.3 ~ 3.5 kΩ Defective = any other reading T-31 LMVM2277ST...
Page 104: Ventilation Fan Motor
Ventilation Fan Motor T-31 LMVM2277ST...
Page 105 Rx1. NORMAL: Blue & Black 4 ~ 20 Ω TURBO Blue & White 19 ~ 35 Ω HIGH Blue & Gray 26 ~ 42 Ω MEDIUM Blue & Brown 34 ~ 50 Ω DEFECTIVE: Infinity T-31 LMVM2277ST...
Page 106: Humidity Sensor
Humidity Sensor T-31 LMVM2277ST...
Page 107 10%. Infinite resistance or a dead short indicates a sensor failure. 1 and 3 (Black & red) 6 kΩ 2 and 3 (Red & white) 3 kΩ 1 and 2 (Black & white) 3 kΩ T-31 LMVM2277ST...
Page 108: Stirrer Fan Motor
Stirrer Fan Motor T-32 LMVM2277ST...
Page 109 Stirrer Fan Motor Remove the connector and measure the resistance across the terminals using meter scale Rx1000. Normal = 120 ~ 135 Ω Defective = any other reading (See page 21.) T-32 LMVM2277ST...
Page 110: Microwave Leak Test
Microwave Leak Test If the oven is operational, it should be checked for microwave leakage before servicing begins. The standard for microwave emission is 5mW/cm2. LG’s voluntary standard is much lower at 1mW/cm2. A microwave leakage test MUST be performed after the oven is serviced for any reason.
Page 111 Holaday HI-1500 or HI-1501 or a Narda 8100 or 8200 non-conductive, 600 cc beaker (glass or plastic) approximately 3½ inches (900 mm) in diameter glass thermometer 32° F to 212° F (0° C to 100° C) in 1° graduations T-33 LMVM2277ST...
Page 112 Microwave Leak Test Procedure: Pour 275±15 cc of water into the beaker Verify the temperature to be 68° F ±9° F (20° C ±5° C) Set the leakage meter to 2,450 MHz Use the 2-inch (5 cm) spacer T-33 LMVM2277ST...
Page 113 Operate the oven at high (maximum) output Check for microwave emissions by holding the probe perpendicular (a 90° angle) to the surface and scanning less than 1 inch (2.5 cm) per second in the area shown in the diagram. T-33 LMVM2277ST...
Page 114: Microwave Power (Traditional)
Microwave Power (Traditional) Magnetron output and microwave power tend to deteriorate with age. To determine whether an oven’s output is within specification, use the following formula and procedure. FORMULA P = 4.187 Mw (T2-T1) + 0.55 Mc (T2-T0) T-34 LMVM2277ST...
Page 115: Microwave Power
°C initial temperature of the water, in °C final temperature of the water, in °C heating time, in seconds, excluding the magnetron filament warm-up time T-34 LMVM2277ST...
Page 116 Microwave Power After inspecting or servicing the magnetron, ensure the gasket is properly installed around the dome of the tube. Check for microwave leakage following the procedure on page 33. T-34 LMVM2277ST...
Page 117: Microwave Power (Alternate Method)
Microwave Power Output testing requires the ability of the technician to measure water temperature in degrees Celsius (ºC), to have two (2) - one (1) liter plastic measuring beakers, and a voltmeter that is capable of measuring 120 VAC with ± 1 volt accuracy. T-35 LMVM2277ST...
Page 118 Microwave Power Equipment Celsius thermometer Two – 1-Liter Plastic Beakers (Plastic does not absorb heat energy like glass!) AC Voltmeter T-35 LMVM2277ST...
Page 119 Fill both of the 1-liter beakers to the 1000 ml (1 Liter) measuring line. Stir the water and determine that the tap water is cooler than 25º C; record the temperature. If the temperatures differ, added the 2 numbers and divide by 2 to get an average. T-35 LMVM2277ST...
Page 120 2 minutes. Press the START button and heat the water for 2 minutes. After heating for 2 minutes, immediately remove the beakers, stir the water with the thermometer, and record the water temperature of both beakers. 2 T-35 LMVM2277ST...
Page 121 This could affect the ending temperatures of both beakers water. If the water temperature in the 2 beakers differs, add the two Celsius numbers and divide by 2 to get the average ending temperature. T-35 LMVM2277ST...
Page 122 = 32.5º C 1st Beaker 36.5° C 2nd Beaker 32.5° C Total 69.0° C Average the sum by dividing by 2 69 ÷ 2 = 34.5° av. temp Subtract the starting Temperature is: - 20° start temp temperature rise 14.5° T-36 LMVM2277ST...
Page 123 Measure the voltage under load at the wall receptacle where the oven is powered and operating. The following chart shows the percentages of full power that are within limits at voltages from 108 V to 132 V . (See chart, next slide.) T-36 LMVM2277ST...
Page 124 Microwave Power 125% HIGH LIMIT 120% 115% 110% NOMINAL 105% 100% LOW LIMIT 108 110 112 114 116 118 120 122 124 126 128 130 132 SUPPLY VOLTAGE T-35 LMVM2277ST...
Page 125 108 VAC. Below this point the power output drops sharply in an unpredictable manner. Likewise, operating an oven at voltages greater than 132 VAC should be avoided as damage to components may occur due to excessive electrical pressure. T-35 LMVM2277ST...
Page 126 85% and 112% of the rated power. 85% of 1000 = 850 watts 112% of 1000 = 1120 watts Therefore, the oven would be nominal (normal) if the output power was between 850 watts to 1120 watts. T-37 LMVM2277ST...
Page 127 When the power output measured falls outside the nominal (normal) range on the chart, take the following steps: If no other parts are defective and line voltage under a load is within tolerance, replace the magnetron and retest. T-37 LMVM2277ST...
Page 128 A layer short circuit of the high voltage transformer may cause a low power output. If burned places are found in the high voltage transformer and a smell of burning insulation is sensed, replace the high voltage transformer. T-37 LMVM2277ST...
Page 129: Checkout Procedures
Checkout Procedures The following procedures are offered to the servicer in the interest of saving time and isolating a problem quickly to provide a fast repair. T-38 LMVM2277ST...
Page 130: Blown Fuse
Fuse blows immediately monitor switch. Check and when door is opened. adjust as necessary. Fuse blows immediately Malfunction of high voltage when START is pressed transformer circuit, including with door closed. transformer, diode, capacitor, magnetron, blower motor, or main board. T-38 LMVM2277ST...
Page 131: Main Pcb (Printed Circuit Board)
If the input current is more than 20 amps, check the magnetron and related wiring. If the input current is less than 0.5 amps, there is no input to the high voltage transformer. START fails but high voltage, interlock switches, door sensing, and relay check good. T-38 LMVM2277ST...
Page 132 Oven operates continuously with a normal relay. Buzzer sounds continuously or fails to sound. Segments of the LED display fail to light, light continuously, or light when they should not. Incorrect numbers or letters appear in the display. Clock fails to keep time accurately. T-38 LMVM2277ST...
Page 133 Relay Fan turns on when door is closed but START is not pressed. T-39 LMVM2277ST...
Page 134 Relay Fan does not turn on when door is closed and START is pressed. T-39 LMVM2277ST...
Page 135 Relay Oven lamp turns on when door is closed without pressing START T-40 LMVM2277ST...
Page 136 Relay Oven lamp does not turn on when door is closed and START is pressed. T-40 LMVM2277ST...
Page 137: Troubleshooting Flowcharts
Before starting the troubleshooting charts, check to see if the oven is operable. For display problems, use charts A, B, and C. If the oven does not heat, try charts D and E. If the ventilation fan does not operate, use chart F. T-41 LMVM2277ST...
Page 138: Chart A - No Power
Chart A – No Power Check connector CN1 on the main board. Reading across pins 1 and 3, (blue wire and white wire) the voltage should be 120 V T-41 LMVM2277ST...
Page 139: Chart B - Power But Doesn't Run
Chart B – Power But Doesn’t Run Check the continuity of connector CN3 between pins 1 (PK-pink) and 3 (BL-black) when the door is closed. T-42 LMVM2277ST...
Page 140: Chart C - Runs But No Heat
Pins A and B – 11 Ω ± 2 Ω If the fan motor is defective, it will also affect the stirrer fan motor, because the center tap if the main fan motor provides the 21 VAC supply for the stirrer fan. T-43 LMVM2277ST...
Page 141 Chart C - continued T-43 LMVM2277ST...
Page 142: Chart D - Runs But No Heat
Chart D – Runs But No Heat Check the primary and secondary interlock switches. Check both thermostats (TCO) for the oven cavity and the magnetron. Either switch could render the oven inoperable. Check the relay T-44 LMVM2277ST...
Page 143 Chart D - continued Check the resistance of the high voltage transformer. (See page T-27.) Check the high voltage capacitor. (See page T-28.) Check the high voltage diode. (See page T-30.) T-45 LMVM2277ST...
Page 144 Chart E – Beeper Beepeth Not Check the PCB (Printed Circuit Board) and all connectors. T-46 LMVM2277ST...
Page 145: Chart F - Power Supply
Chart F – Power Supply Check the ventilation fan for proper operation. T-47 LMVM2277ST...
Page 146 Main Board Connectors labeled. T-48 LMVM2277ST...
Page 147: Exploded View
Exploded View T-49~54 LMVM2277ST...
Page 148: Parts List
Parts List The parts list is provided for your convenience to ensure that the part you have in your hand or on the truck is indeed the correct part number. Always order parts by MODEL and SERIAL NUMBER. T-55~57 LMVM2277ST...
Page 149 Serial Numbers [Example] 801KW3400251 8 0 1 K W 0 0 2 5 1 Production Number [Internal code] Made in Korea Manufactured January 2008 T-55 LMVM2277ST...
Page 150: Serial Numbers
Serial Numbers New Serial Code (ETA Mid 2008) 12345 KR 406 YP 000002 + Options Sequential number Internal code Year and month of production (YMM) Production site (2 Letters) Model ID T-55 LMVM2277ST...
Page 151 Part No Description MFL37191403 Manual, Owners MFL06272504 Manual, Service MFL06208702 Manual, Installation MEZ37728002 Label, Cooking Guide *06-1 4922W5A060A Card, Template *06-2 MBM38968801 Card, Template MAY39948401 13213A ADV32254902 Frame Assembly, Door 13536A 3536W1A007G Tape, Sealing 13550L MCK36295901 Cover, LED T-56~58 LMVM2277ST...
Page 152: Additional Information - Ohm's Law
Watts = Volts x Amperes Amperes = E = VOLTS R = OHMS Ohms = Volts / Amperes Volts = Ohms = Volts / Amperes Volts = Watts / Amperes Volts = Amperes x Ohms Ohms = Watts / Amperes T-60 LMVM2277ST...
Page 153: Chart - Ohm's Law
Chart – Ohm’s Law T-60 LMVM2277ST...
Page 154: Temperature Conversion
Temperature Conversion °F = (9/5) °C + 32 ° C = (5/9) x ( ° F – 32) T-16 LMVM2277ST...
Page 155 Schematic New and improved, on a double-sized page folded in the back of the training manual. LMVM2277ST...
Page 156 LMVM2277ST...

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