LG LMVM2033ST (01) PDF DOCUMENT

The specifications for the LG LMVM2033ST are as follows:

Rated Power Consumption: 1600W maximum (Microwave oven + Cook top lamps + Ventilation fan)

Microwave Output: 1000W (IEC60705)

Frequency: 2450 MHz ±50 MHz

Power Supply: 120 VAC, 60 Hz

Rated Current: 14 Amp. (Microwave oven + Cook top lamps + Ventilation fan)

Magnetron Cooling: Forced Air Cooling

Rectification: Rectification Voltage Double Half-Wave

Door Sealing: Choke System

Safety Devices: OVEN TCO 110/0, MGT TCO 180/60, Bottom TCO: 145/0, Fuse (20A), Primary Interlock Switch, Secondary Interlock Switch, Interlock Monitor Switch

Magnetron: 2M246 – 050GP

Cook Top Lamp: Halogen lamp, 130V, 50W

Cavity Lamp: 125 V, 30 W or 40 W

Timer: Digital, up to 99 min. 99 sec. (in each cooking stage)

Tray: Tempered Safety Glass

Overall Dimensions: 29 14/16″ (W) x 16 7/16″ (H) x 15 13/16″ (D)

Oven Cavity Size: 22 (W) x 11 5/8″ (H) x 14 5/8″ (D)

Effective Capacity of Oven Cavity: 2.0Cu.ft.

Accessories: Owner’s Manual & Cooking Guide, Installation Manual, Exhaust Adapter, Exhaust Damper, Mounting Kit and Filter, Glass Tray, Metal Rack, Rotating Ring Assembly.

The switch chart below explains the state of the interlock switches for the LG LMVM2033ST when the door is open and closed.

Here is an explanation of each control panel button for the LG LMVM2033ST:

1. AUTO REHEAT: Press this button to reheat a dinner plate, soup/sauce, casserole, or roll/muffin.

2. AUTO COOK: Press this button to cook fresh vegetables, frozen vegetables, rice, or casseroles.

3. POPCORN: Press this button when popping popcorn in your microwave oven.

4. DEFROST: Touch this button to defrost frozen food.

5. SOFTEN: Press this button to soften butter, ice cream, cream cheese, or frozen juice.

6. MELT: Press this button to melt butter or margarine, chocolate, cheese, or marshmallows.

7. CUSTOM COOK: Touch this button to make the oven remember a Cook time and Power level.

8. POWER LEVEL: Press this button to select a cooking power level.

9. DISPLAY: The display includes a clock and indicators to tell you the time of day, cooking time settings, and cooking functions selected.

10. NUMBER: Press this button to enter cooking time, power level, quantities, or weights.

11. +, -: Touch this button to add or subtract ten seconds of cooking time each time you touch it.

12. ADD 30 SEC: Press this button to control the add 30sec. cook time.

13. START/ENTER: Press this button to start a function. If you open the door after the oven begins to cook, press START/ENTER again.

14. LIGHT HIGH/LOW/OFF: Touch this button to turn the cooktop/countertop light on high/low or off.

15. KIDS MEAL: Select the type of dish to reheat: HOT DOG, MAC & CHEESE, or CHICKEN NUGGETS.

16. CLOCK: Press this button to enter the time of day.

17. TIMER: Use this to set a kitchen timer.

18. COOK TIME: Press this button to set a cooking time.

19. CUSTOM SET: Touch this pad to change the oven’s default setting for sound, clock, display speed, and defrost weight.

20. TURNTABLE ON/OFF: Press this button to turn the turntable on or off.

21. ENERGY SAVING: Press this button to save energy.

22. STOP/CLEAR: Press this button to stop the oven or clear all entries.

23. VENT ON/OFF: Touch this button to turn the vent on slow or off.

24. VENT 4 SPEED: Touch this button to change vent speed.

25. VENT AUTO TIMESET: Touch this button to set ventilation time (1, 3, 5, 10, and 30 minutes).

To avoid possible exposure to excessive microwave energy, observe the following precautions before and during servicing:

a. Do not operate or allow the oven to be operated with the door open.

b. Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary: (1) Interlock operation, (2) proper door closing, (3) seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and latches, (5) evidence of dropping or abuse.

c. Before turning on microwave power for any service test or inspection within the microwave generating compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and connections.

d. Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and transmission systems shall be repaired, replaced, or adjusted by procedures described in the manual before the oven is released to the owner.

e. A microwave leakage check to verify compliance with the federal performance standard should be performed on each oven prior to release to the owner.

Additionally, please note these cautions:

• The microwave oven is high-voltage and high-current equipment. Extreme care should be taken during repair.

• DO NOT operate on a 2-wire extension cord.

• NEVER TOUCH any oven components or wiring during operation.

• BEFORE TOUCHING any parts of the oven, always remove the power plug from the outlet.

• DO NOT touch any parts of the control panel circuit, as a static electric discharge may damage the P.C.B.

• NEVER operate the oven with no load.

• NEVER injure the door seal and front plate of the oven cavity.

• Be sure that the magnetron gasket is properly installed around the dome of the tube whenever installing the magnetron.

Follow these precautions for installing your LG LMVM2033ST:

A. Plug the power supply cord into a 120V AC, 60Hz, single-phase power source with a capacity of at least 20 amperes.

B. Avoid placing the unit in a location where there is direct heat or splashing water.

C. Install the unit on the mounting plate firmly.

D. Place the unit as far away as possible from TV, radio, etc. to prevent interference.

Grounding Instructions:

For personal safety, this appliance must be fully grounded at all times. In the event of an electrical short circuit, grounding reduces the risk of electric shock. The plug must be plugged into an outlet that is properly installed and grounded. This unit is equipped with a 3-prong plug for your safety. If the wall outlet is a grounded 3-hole type, the unit will be grounded automatically. Improper use of the grounding plug can result in a risk of electric shock. Do not, under any circumstances, cut or remove the third ground prong from the power cord plug.

After installation, the following sequences and results should be checked carefully:

A. Put a container filled with water (about 1 liter) into the oven, and close the door tightly.

B. Set cooking time for 10 minutes by touching 1 and then 0 three times. “1, 0, 0, 0” appears in the display window.

C. Press the START button. Make sure the cavity light comes on. The unit will begin cooking and the display window will show the time counting down by seconds.

D. After about 5 minutes, make sure the primary interlock switch, the secondary interlock switch and the interlock monitor switch operate properly by opening and closing the door several times. Press the START button each time the door is closed.

E. Continue operating the unit. Two short beeps and one long beep will sound when the time is up. The unit will shut off automatically.

F. Confirm the water is hot.

G. Finally, measure the output power according to the POWER OUTPUT MEASUREMENT procedure.

A. Never operate the unit when it is empty. Operating the oven with no load may shorten the life of the magnetron. Whenever cooking dry foods (dried fish, bread, etc.) or a small amount of food, be sure to put a glass of water into the cooking compartment. The glass turntable may become hot after operating, be careful when touching it.

B. Aluminum foil should be avoided because it will disrupt cooking and may cause arcing. However, small pieces may be used to cover some parts of food to slow the cooking. Any aluminum foil used should never be closer than 1 in. (2.5 cm) to any side wall of the oven.

To run the self-diagnosis for the humidity sensor and PCB thermistor on your LG LMVM2033ST, follow these steps:

1. Press “Defrost weight/time” for 2 seconds. The unit will display “TEST” and beep once.

2. The unit will check if the PCB humidity sensor and PCB thermistor are short or open.

3. If it has an error, it will beep and display an error code. If the unit is normal, it will beep and display “PASS”.

4. Press “Clear” to return to Standby mode.

The error codes are as follows:

If there is no display or the LG LMVM2033ST appears dead, follow these troubleshooting steps:

1. Check for Beeping Sound: When you push any key, do you hear a beeping sound? If yes, proceed to step 6. If no, continue to the next step.

2. Check Connector to PCB: Is the main power connector properly connected to the Printed Circuit Board (PCB)? If no, reconnect or repair the connector. If yes, proceed to the next step.

3. Check Power Cord Continuity: Perform a continuity test between the power cord prongs and the corresponding pins on the connector (Code “L” to Pin1, Code “N” to Pin3). If there is a beep (continuity), check the PCB and proceed to step 6. If no, there is an issue with the power cord.

4. Check Fuse: Perform a continuity test between the two ends of the main fuse. If there is no beeping sound, replace the fuse. If there is a beep, proceed to the next step.

5. Check Noise Filter: Perform a continuity test between the input and output ends of the noise filter. If there is no beeping sound, replace the noise filter.

6. Replace PCB: If all previous checks are normal, the main PCB may be faulty. Replace the PCB (Part No. EBR75341201).

If the keys on your LG LMVM2033ST are not operating, follow this procedure:

1. Check START key: With the door closed, do only the START and EZ-ON keys operate? If yes, proceed to step 3. If no, the PWB (Printed Wiring Board) may be at fault; proceed to step 4.

2. Check Latch Board Switch: With the door closed, perform a continuity test between the ends of the secondary switch on the latch board. If there is no beeping sound (no continuity), adjust the latch board. If there is continuity, proceed to the next step.

3. Check Door Sensing Voltage: When the door is opened, check the voltage of the door sensing part (CN3 Pin1 and Pin2). Is it over 4V? If no, replace the PCB (EBR75341201). If yes, continue.

4. Check Connector to PCB: Is the keypad connector to the PCB disconnected or disassembled? If yes, reconnect or repair the connector. If no, proceed to the next step.

5. Check Keypad: If the issue persists, the keypad itself may be faulty. Try replacing the keypad.

6. Replace PCB: If replacing the keypad does not solve the issue, replace the main PCB (EBR75341201).

If your LG LMVM2033ST is running but not heating, perform the following checks. CAUTION: High voltage components are dangerous. This is best performed by a qualified technician.

1. Check Door Operation: After turning the power on, does the product operate? Repeat opening and closing the door at least three times. If it still does not operate, check if something is caught in the door or sealing area preventing safe operation.

2. Check Relay 2 Voltage: While the product is operating under an EZ-ON start, is the voltage of both ends of the D35 diode over 8V? If yes, the Relay 2 may be faulty. If no, replace the PCB (EBR75341201).

3. Check Latch Board Continuity (Power Off): With the door closed, is there a beeping sound in the continuity test between the ends of the latch board? If no, adjust the latch board. If yes, proceed.

4. Check High Voltage Transformer Connector: Is the connector to the High Voltage Transformer assembly disconnected? If yes, reconnect or repair it.

5. Check High Voltage Transformer Resistance: Is the resistance of the high voltage transformer out of range? (Primary winding: 0.2-0.5 Ohm; Secondary: 50-120 Ohm; Filament: 0 Ohm). If yes, replace the High Voltage Transformer.

6. Check High Voltage Capacitor: Is the connector loose? Is the resistance out of range when tested? If yes, replace the high voltage capacitor.

7. Check High Voltage Diode: Is the connector loose? Is the resistance out of range when tested (should have continuity in forward direction, infinite in reverse)? If yes, replace the high voltage Diode.

8. Check Magnetron: Is the connector loose? If so, reconnect it. If the checks above are all normal, the magnetron may be faulty.

If the turntable motor on your LG LMVM2033ST does not work, follow these steps with the power on:

1. Check Turntable Motor Operation: Does the turntable motor operate at all? If no, the turntable motor itself may need to be replaced. If yes, proceed to the next step.

2. Check Oven Lamp: When the door is closed, does the oven lamp turn on? If yes, you may need to adjust the Primary latch board. If no, proceed to the next step.

3. Check D37 Voltage: Push the EZ-ON button to operate the oven. Is the voltage across both ends of the D37 diode over 8V? If no, replace the PCB (EBR75341201).

4. Check RY1 Continuity: Is there a beeping sound in the continuity test between the two pins of Relay 1 (RY1)? If no, replace the PCB (EBR75341201).

5. No PCB Problem: If all tests pass, there is no problem with the PCB related to this function.

If your LG LMVM2033ST starts automatically, follow this troubleshooting guide:

1. Check Door Operation: Repeat opening and closing the door at least three times. Does the product still operate automatically? If not, check if something was caught in the door. If it still operates automatically, continue.

2. Check Latch Board Switch: With the door closed, perform a continuity test between the ends of the secondary switch on the latch board. If there is no continuity, adjust the latch board. If there is continuity, proceed.

3. Check Oven Lamp (Power ON): When the door is closed, does the oven lamp turn on? If no, replace the turntable motor.

4. Check Door Sensing Voltage: When the door is opened, is the voltage of the door sensing part (Pin 11 to Pin 12) over 4V? If no, replace the PCB (EBR75341201).

5. Check D37 Voltage: Is the voltage of both ends of the D37 diode over 8V? If no, replace the PCB (EBR75341201).

6. Check RY1 Continuity: Is there continuity between the two pins of Relay 1 (RY1)? If no, replace the PCB (EBR75341201). If yes, there is no PCB problem related to this issue.

To measure microwave energy leakage, you will need a microwave survey meter, a 600 cc non-conductive beaker, and a glass thermometer. This test should be performed by qualified service personnel.

1. Pour 275±15cc of 20±5°C (68±9°F) water into the beaker and place it in the center of the oven.

2. Set the energy leakage monitor to 2,450 MHz and use it following the manufacturer’s recommended test procedure to ensure a correct result.

3. When measuring the leakage, always use the 2-inch (5cm) spacer supplied with the probe.

4. Operate the oven at its maximum output.

5. Measure the microwave radiation by holding the probe perpendicular to the surface being measured. Move the probe along the door edges, viewing window, and vent openings.

6. The probe scanning speed should be less than 2.5 cm/sec (1 in/sec).

The power density of the microwave radiation leakage emitted by the microwave oven should not exceed 1 mW/cm². The federal performance standard is 5 mW/cm².

The door lock mechanism is a critical safety feature. To check and adjust it:

Check the Door Latch and Switch Closing:

1. Set the microwave oven on its side so you can see the latch board and the switches.

2. Close the door tightly and check gaps A and B (clearance between latch head and switch body). If all gaps are less than 1/64″ (0.5 mm), adjustment may not be necessary. If any gap is larger, you must adjust the latch board.

Adjust the Latch and Switch Closing:

3. Loosen the two screws holding the plastic latch board.

4. With the oven door closed tightly, move the latch board upward toward the top of the oven and/or away from the door latch until the gaps are less than 1/64″ (0.5 mm). Hold the latch board tightly in this position and proceed.

Test the Latch and Switch Sequence:

5. Open the oven door slowly. Watch the door latch and switches. They should release in the following sequence: Primary Interlock Switch, Secondary Interlock Switch, Interlock Monitor Switch.

6. Close the oven door slowly and ensure it is tightly closed. Watch the three switches engage in the following sequence: Interlock Monitor Switch, Primary Interlock Switch, Secondary Interlock Switch.

7. When you achieve the proper sequence, tighten the latch board screws at that point.

NOTE: The Interlock Monitor Switch is an added safety check. If the Primary and Secondary Interlock Switches allow the oven to operate with the door open, the Monitor Switch will blow the fuse.

After disconnecting the power, you can test the switches with an ohmmeter. The wire leads must be removed from the switch for testing.

If any switch operates abnormally, make the necessary adjustment or replace the switch with an identical replacement part.

IMPORTANT: The unit must be disconnected from the electrical outlet before starting.

(1) Remove the screw securing the control panel assembly to the oven cavity.

(2) Remove the control panel by pushing it upward.

(3) Remove the connectors (cn1, cn3, cn5) and wire leads (RY1, RY2) from the circuit board.

(4) Remove the 5 screws securing the circuit board to the control bracket.

(5) Remove the FPC connector from the terminal socket.

(6) Remove the circuit board from the control bracket carefully.

(1) Remove the vent grille by removing the two screws securing it to the outer case.

(2) Remove the two screws securing it to the air duct.

(3) Remove the mounting plate by loosening the screws (1 or 2 screws) securing it to the outer case.

(4) Remove two screws on the left central edge and one screw on the right central edge of the base plate. Remove the fan bracket from the outer case by removing one screw securing it to the outer case.

(5) Remove six screws of the rear cavity.

(6) Remove the outer case.

Removing the Door Interlock Switches:

(1) Disconnect the wire leads from the interlock switches.

(2) Remove the two screws securing the Latch Board.

(3) Make any necessary replacements and check for microwave energy leakage according to adjustment procedures.

Removing the Door:

(1) Remove the vent grille by loosening the two screws securing it to the outer case.

(2) Lift up and draw out the door.

NOTE: After replacing the door, be sure to check that the primary interlock switch, the secondary interlock switch, and the interlock monitor switch are in good operating condition. Also, check for microwave energy leakage.

WARNING: High voltage components are present. Disconnect power before proceeding. This should be performed by a qualified technician.

(1) Remove the vent grill by loosening the one screw.

(2) Remove the fan bracket and outer case.

(3) Remove the four tap-tite screws securing the magnetron to the wave guide.

(4) Disconnect the lead wire.

(5) Remove the magnetron VERY CAREFULLY.

NOTES:

• When removing the magnetron, make sure that its dome does not hit any adjacent parts, or it may be damaged.

• When replacing the magnetron, be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition.

• After replacing the magnetron, check for microwave energy leakage with a survey meter.

(1) Remove the glass tray and rotating ring.

(2) Remove the turntable shaft VERY CAREFULLY with one hand.

(3) Remove the base plate by removing the 8 screws securing it to the oven cavity.

(4) Disconnect the lead wire from the turntable motor terminals.

(5) Remove the 1 screw securing the turntable motor to the oven cavity assembly.

NOTES:

• Remove the lead wire from the turntable motor VERY CAREFULLY.

• Be sure to grasp the connector, not the wires, when removing.