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LG LSWS305ST Service Manual

3" electric convection built-in oven
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30" ELECTRIC CONVECTION
BUILT-IN OVEN
SERVICE MANUAL
MODEL: LSWS305ST
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL37118308
Website http://biz.lgservice.com
1
Internal Use Only
March, 2010
Printed in Korea

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  Summary of Contents for LG LSWS305ST

  • Page 1 삼 흥 정 판 Internal Use Only Website http://biz.lgservice.com 30” ELECTRIC CONVECTION BUILT-IN OVEN SERVICE MANUAL MODEL: LSWS305ST CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. March, 2010 P/NO : MFL37118308 Printed in Korea...
  • Page 2: Safety Precautions

    SAFETY PRECAUTIONS • Repairs of the appliance should be carried out by a licensed technician only. Incorrect repairs may result in dangerous situations. If you need repairs, contact an LG Service Center or your dealer. • If the power cord is defective, it must be replaced by a qualified service agent with a UL listed range cord.
  • Page 3: Table Of Contents

    TABLE OF CONTENTS GENERAL- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1-1 ~ 1-6 •...
  • Page 4 - Removing the Vent motor - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3-6 - Removing the Thermal limiter - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3-7 - Removing the Door switch - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3-7 - Removing the Thermal limiter (Double Line Break) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3-8...
  • Page 5: General

    GENERAL READ ALL INSTR UCTIONS BEFORE USE READ ALL INSTR UCTIONS BEFORE USE Read and follow all instructions before using your oven to prevent the risk of fire, electric shock, injury to person, or damage when using the range. This guide don’t cover all possible conditions that may occur. For further assistance contact your service agent or manufacturer.
  • Page 6 GENERAL READ ALL INSTR UCTIONS BEFORE USE READ ALL INSTR UCTIONS BEFORE USE SAFETY PRECAUTIONS • Be certain all packing materials are removed • Be certain your appliance is properly installed from the appliance before operating. and grounded by a qualified technician. Keep plastics, clothes, and paper away from •...
  • Page 7 GENERAL READ ALL INSTR UCTIONS BEFORE USE READ ALL INSTR UCTIONS BEFORE USE • Before replacing your oven light bulb, switch CHILD SAFETY off the electrical power to the oven at the main fuse or circuit breaker panel. WARNING Failure to do so can result in severe personal injury, death, or electrical shock.
  • Page 8 GENERAL READ ALL INSTR UCTIONS BEFORE USE READ ALL INSTR UCTIONS BEFORE USE SAFETY WHEN CLEANING • Important Instruction. In the event the self • Do Not Clean Door Gasket. The door gasket is clean error code F is displayed, and error essential for a good seal.
  • Page 9 GENERAL MODEL & SERIAL NUMBER LABEL AND MODEL & SERIAL NUMBER LABEL AND TECH SHEET LOCA TION TECH SHEET LOCA TION The Model/Serial Number label and Tech Sheet locations are shown below. Model & Serial Number Location Tech Sheet Location...
  • Page 10: Specifications

    SPECIFICA TIONS SPECIFICA TIONS Product Specification List Items Specifications Remarks Model name LSWS305ST Built-in Single wall oven North American market Rating power source 240 V~ 60 Hz Single phase & 4-wires Heat source Sheath heater & Carbon heater Max power 4.1 KW...
  • Page 11: Using Your Oven

    USING YOUR OVEN GENERAL INFORMA TION GENERAL INFORMA TION Cooking Guide Rating Label Refer to the owners manual for recommendations Model numbers are recorded on the rating label. of times and temperatures. Times, rack position, Rating label is located on the lower left bottom and temperatures may vary depending on area of the controller.
  • Page 12: Control Panel Feature

    USING YOUR OVEN CONTR OL P ANEL FEA TURES CONTR OL P ANEL FEA TURES READ THE INSTRUCTIONS CAREFULLY BEFORE USING THE OVEN. For satisfactory use of your oven, become familiar with the various features and functions of the oven as described below. 1.
  • Page 13: Setting The Initial Control

    USING YOUR OVEN 1. SETTING THE INITIAL CONTROL 3) Hour and Min setting 1) LG logo display 8 seconds. - Initial display NUMERIC (Set the TIMER TIMER TIMER (Power Failure or Reset) desired time-hour and min) First, Select Language, and set clock time, and then the oven can be used.
  • Page 14: Bake

    USING YOUR OVEN 3) Display brightness 7) Clock Time 1. Requirement: LCD Display Brightness 1. Requirement: The clock key is used to set the adjustment clock in idle mode. The clock can be set to 12 2. Key Input Process or 24 hour format.
  • Page 15: Broil

    USING YOUR OVEN 9. BROIL 16. HEALTHIER ROAST Healthier Selected food Desired Broil Broil Roast category Full / Center Desired Desired Temp START START Temperature High / Med / Low 10. ROAST * Note: The meat probe must be used in this feature.
  • Page 16: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS This section instructs you on how to service each component inside the oven. The components and their locations are shown below. COMPONENT LOCA TIONS COMPONENT LOCA TIONS Main PCB Display PCB Low Voltage Transformer Side Key PCB Upper Oven Light Upper Door Latch Assembly Oven Sensor...
  • Page 17: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS REPLA CING THE CONTR OL P ANEL AND RELA TED COMPONENTS REPLA CING THE CONTR OL P ANEL AND RELA TED COMPONENTS 6. Disconnect the 8EA connector from PCB assembly WARNING (CN01, CN02, CN03, CN04, CN08, CN11) and separate control panel carefully.
  • Page 18: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS 2) To remove the Relay PCB, Remove 1 screw TO UNLOCK THE OVEN DOOR MANUALLY and slide relay PCB out. In case of need, the oven door could be unlocked Disconnect the 7EA connector from PCB manually for the service. Follow the steps below. assembly(CN01, CN02, WH, WH, VI, YL, Unlocking status Locking status...
  • Page 19 DISASSEMBLY INSTRUCTIONS REPLA CING O VEN CA VITY COMPONENTS REPLA CING O VEN CA VITY COMPONENTS 1) To remove the broil element: WARNING a. Remove the 4 screws from the front and rear brackets. • ELECTRIC SHOCK HAZARD - Unit must be disconnected from electrical outlet when making repairs, replacements, adjustments.
  • Page 20 DISASSEMBLY INSTRUCTIONS b. Remove the 4 convection element screws. 4) To remove the halogen lamp & socket assembly (The convection element is fragile. Care a. There are three halogen lamp & socket should be taken to avoid any risk of injury) assembly in the oven cavity.
  • Page 21: Replacing Other Electrical Components

    DISASSEMBLY INSTRUCTIONS REPLA CING O THER ELECTRICAL COMPONENTS REPLA CING O THER ELECTRICAL COMPONENTS Thermal limiter Vent motor WARNING • ELECTRIC SHOCK HAZARD - Unit must be disconnected from electrical outlet when making repairs, replacements, adjustments. Replace all panels before operating oven.
  • Page 22: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS COOLING FAN (BLOWER) 4) Squeeze tabs on switch and slide through the front. • Self Clean Mode: The cooling fan can operate Disconnect the wires from terminals. at 2 different speeds based on temperature. If the temp is above 482°F/250°C the fan will operate on high.
  • Page 23 DISASSEMBLY INSTRUCTIONS 1) To Remove Thermal Limiter (Double Line 3) To remove the hidden bake element Break), remove the screw and 2 wire leads. a. Remove the Barrier bracket. THERMAL LIMITER • To shut down the heaters The thermostat is located at the back of the oven next to the broil element and wired in series with the Double Line Break relay.
  • Page 24 DISASSEMBLY INSTRUCTIONS d. Bend the insulator up and remove the 1 screw. e. Carefully pull the hidden bake element out of the oven. f. When replacing the Bake Element cover use the 5 screws provided.
  • Page 25: Removing & Reinstalling The Lift-Off Oven Door

    DISASSEMBLY INSTRUCTIONS REMO VING & REINST ALLING THE LIFT -OFF O VEN DOOR REMO VING & REINST ALLING THE LIFT -OFF O VEN DOOR To replace the door: CAUTION 1. Firmly grasp The door is very heavy. Be careful both sides of the door at the top.
  • Page 26 DISASSEMBLY INSTRUCTIONS REMO VING THE O VEN DOOR HANDLE & GLASS REMO VING THE O VEN DOOR HANDLE & GLASS 6. To remove the door handle & trim. CAUTION a. Remove 2 screws for handle and replace. • Be careful when you work on the b.
  • Page 27 DISASSEMBLY INSTRUCTIONS 5) Lift the COVER_INNER-2 off the door liner. 6) Lift the hinge out of the door liner slot. To remove the oven door glass assembly: 7) Lift the COVER_INNER-1 off the door liner. COVER_INNER-1 COVER_INNER-1 COVER_INNER-1 COVER_INNER-1 COVER_INNER-1 COVER_INNER-1 COVER_INNER-1 COVER_INNER-1...
  • Page 28: Removing The Oven Door Gasket

    DISASSEMBLY INSTRUCTIONS REMO VING THE O VEN DOOR GASKET REMO VING THE O VEN DOOR GASKET 1. Remove oven door 3. Pull the ends of the gasket out of the liner holes. 2. Pull the oven door gasket clips out of the liner Liner Hole holes until all of the clips are removed.
  • Page 29: Component Test

    COMPONENT TEST Before testing any components, perform the following checks: NOTE: 1. The most common cause for control failure is corrosion on connectors. Therefore, disconnecting and reconnecting wires will be necessary throughout test procedures 2. If this is a new product check all connections before replacing parts. 1.
  • Page 30: Door Locking Motor

    Components Test procedures Results Normal: Approximately 2550 Ω Door locking Motor 1. Refer to page 3-10 for disassembly Replace if: Infinite (opened) 2. Measure the resistance below 5 Ω (shorted) (Multiple meter scale: R x 1000) Door latch Door latch Door locking micro 1.
  • Page 31: Oven Thermistor

    Components Test procedures Results Normal: Approximately Oven Thermistor 1. Refer to page 3-5 for disassembly 1090 Ω 2. Measure the resistance after cool down Replace if: Infinite (opened) (Multiple meter scale: R x 1000) below 10 Ω (shorted) NOTE: Ω Value should be tested at room temperature (77F/25˚C) NOTE: After checking for the continuity of switch, make sure to reconnect leads...
  • Page 32: Broil Element

    Components Test procedures Results Normal: Approximately Broil Element 1. Refer to page 3-4 for disassembly Inner: 22.5 Ω 2. Measure the resistance after cool down Outer: 36.9 Ω (Multiple meter scale : R x 1) Replace if: Infinite (opened) NOTE: Outer Broil element use Outer yellow and Blue terminals to check resistance.
  • Page 33: Diagnosis Through Schematic

    DIAGNOSIS THROUGH SCHEMATIC Apply schematic from Tech sheet. Symptom : Oven lamp not operating -. Check : Open/Short Symptom : No heating (F-9) -. Check : Open/Short Symptom : Oven hot (F-6) -. Check : All heater Relays Short Symptom : Dead -.
  • Page 34: How To Enter The Test Mode

    If you push START - TIMER - LIGHT - START button in order, you can enter the test mode. It’s possible to enter the test mode after power is on. And any keys should not be pushed, even though LG Logo is disappeared on the screen. ★...
  • Page 35: Safety Caution & Error Code Summary

    SAFETY CAUTION & ERROR CODE SUMMARY 1.1 Safety Caution • Normal State is power OFF, unless described differently as power ON. 1.2 Error Code Summary Code Description Operation Opened Sensor Oven Thermistor remain open for over 1 min, after cook starts Shorted Sensor Oven Thermistor is shorted for over 1 min after cook starts Touch Sensor...
  • Page 36: Checking Flow Chart By Failure Mode

    CHECKING FLOW CHART BY FAILURE MODE Dead Symptom Check Point 1. Dead 1. Check for power to wall oven 2. No Display 2. Check the thermostat. 3. Check the Transformer. 4. Check the System and Display...
  • Page 37: Dead

    CHECKING FLOW CHART BY FAILURE MODE Dead No display Power off Check for loose connector’s. or disconnect CN01, CN02, CN03 between system(CN10) and display(CN10) Fix the connection Connector is ok? Power On Check AC input voltage of oven System PCB - CN01 (pin 1 and 3) Should have 120VAC.
  • Page 38 CHECKING FLOW CHART BY FAILURE MODE Dead Power off Check the Thermostat (open/short) L1 and CN01’s RD color wire N and CN01’s WH color wire Is it 120V AC? If it have the error, it is open state. Is it short? Replace the thermostat.
  • Page 39 CHECKING FLOW CHART BY FAILURE MODE Dead Power On Check the System’s Vcc – CN10’s pin11(Vcc) and pin9 (GND) The voltage should be 4.5 VDC ~ 5.8 VDC. Replace the system PCB Is the voltage OK? Check the Display’s Vcc–CN10’s pin11(Vcc) and pin9 (GND) or C228 or C19 Don’t remove the harness The voltage should be 4.5 VDC ~ 5.8 VDC...
  • Page 40 CHECKING FLOW CHART BY FAILURE MODE Dead Replace the Display PCB Is the voltage OK? Check the System’s PCB Replace the Display PCB...
  • Page 41: Oven Does Not Heat (Including F-9 Error)

    CHECKING FLOW CHART BY FAILURE MODE Oven does not heat (including F-9 error) Symptom : No heating -. Check : Elements Resistance ohms Symptom : No heating -. Check : connection Symptom : No heating -. Check : Open/Short Symptom Check Point No heating 1.
  • Page 42 CHECKING FLOW CHART BY FAILURE MODE Oven does not heat (including F-9 error) No heating(including F-9 error) Disconnect power Check the electric wire connection DLB and and harness of Relay and each heater’s connection. And system PCB and Relay PCB(CN11) Loose connection and disconnection Fix the connection Is connection OK?
  • Page 43 CHECKING FLOW CHART BY FAILURE MODE Oven does not heat (including F-9 error) Measure the Resistor of each heater Between the DLB Relay’s L2 and each heater Relay’s Harness point of Figure 1 (①, ②, ③, ④ and ⑤) (measure the resistance after cooling down) Normal: Resistor Bake...
  • Page 44 CHECKING FLOW CHART BY FAILURE MODE Oven does not heat (including F-9 error) Power On Check the thermistor using the test mode 4.Diagnosis Oven sensor. After value the sensor value are 70˚F ~ 90˚F(at 24˚C) Power Off Check the thermistor’s resistor CN04 pin3, 4 Is the value OK? Normal: approximately 1.09 kΩ...
  • Page 45: Not Operating Key (Including F-3 Error)

    CHECKING FLOW CHART BY FAILURE MODE Not operating Key (including F-3 error) Key operating fail(F-3) Check the connection key pcb’s CN7 and between display pcb and key pcb(CN6) Fix the connection Is connection OK? Replace the control supporter(ITO film+Glass touch PCB) Is Key operating OK? Replace the Display pcb 5-13...
  • Page 46: Lock System Failure(Including F-10 Error)

    CHECKING FLOW CHART BY FAILURE MODE lock system failure(including F-10 error) Just after self-clean start,the door lock motor starts to rotate. During that time if the door lock switch does not operate properly after rotating twice, then supervising circuit detects a Door Lock failure and the F-10 error code appears.
  • Page 47 CHECKING FLOW CHART BY FAILURE MODE lock system failure(including F-10 error) Check the locking motor (measure the resistance) Normal : approximately 2.6 kΩ Abnormal : infinite or below 5 Ω Check the loose connector (Oven main PCB CN08) Replace the locking motor 1 2 3 Is the connection OK? Check the Relay PCB’s electric connection (CN01, CN03)
  • Page 48: Oven Thermistor Failed(Including F-1, F-2 Error)

    CHECKING FLOW CHART BY FAILURE MODE Oven Thermistor failed(including F-1, F-2 error) oven sensing failed (including sensor error) Check the thermistor using the test mode 4. Diagnosis Oven sensor. After value the sensor value are 70˚F~90˚F(at 24˚C) Power Off Check the thermistor’s resistor CN04 pin3, 4 Is the value OK? Normal: approximately 1.09 kΩ...
  • Page 49: Oven Too Hot (Including F-6 Error)

    CHECKING FLOW CHART BY FAILURE MODE Oven too hot (including F-6 error) Oven is too hot(F-6 error) Disconnect power Remove the relay PCB harness and pull the relay PCB forward from case Check the L1(TAB1, 18/TAB6, 20) and all the heater relay welded or not. (AND measure the resistance) Welded Normal...
  • Page 50: Communication Error

    CHECKING FLOW CHART BY FAILURE MODE Communication error → → F-10 error F-10 error (communication error) Check the PCB’s test mode Check the 4.Diagnosis Communication check Ok or NG. Check the connection between the system and display(CN10) Fix the connection Is the connection OK? Check the test mode 1 power check...
  • Page 51: Schematic Diagram

    SCHEMATIC DIAGRAM...
  • Page 52: Strip Circuits

    STRIP CIRCUITS STRIP CIRCUITS Complete the following steps before checking electric oven circuit : 1.Check the line voltage, household fuse or circuit breaker. 2.Check for loose wiring or mis-wiring within electric range. NOTE: The following individual circuits are for use in diagnosis, and are shown in the ON position. Full Broil mode Center Broil mode...
  • Page 53 Crisp Convection mode Conv. Bake & Conv. Roast mode Note: In case of Bake mode, the convection fan will operate only for preheating.
  • Page 54 Bake & Roast mode Self Clean mode...
  • Page 55 Warm & Proof mode...
  • Page 56: Exploded View

    #EV# EXPLODED VIEW INTRODUCTION CONTROLLER PARTS DOOR PARTS CAVITY PARTS MAY000 MFL552 MFL409 MAX171 -7-1-...
  • Page 57: Door Parts

    #EV# DOOR PARTS W257 1703 1000 W225 W149 1040 1121 1120 W256 W149 1401 W149 1030 W256 W225 1009 1402 1008 W256 W149 1703 1704 W149 -7-2-...
  • Page 58: Controller Parts

    #EV# CONTROLLER PARTS W108 2119 2006 2050 W105 2381 W105 2009 2118 W258 -7-3-...
  • Page 59: Cavity Parts

    #EV# CAVITY PARTS 5014 W144 5504 W235 5041 W144 W146 5001 W237 5070 W236 W105 W144 W241 5010 W144 5508 W144 5503 5717 5611 3006 3006 W144 5517 W144 5506 5414 W144 W144 5124 5718 W144 W144 W144 5073 W144 3062 W104 5506...
  • Page 60 #EV# ASSEMBLY W144 W144 3029 W144 3605 3604 W144 W144 3601 W144 3603 3013 3602 W144 W144 3311 W144 5527 W144 W121 3018 3511 W144 3044 3312 3144 5080 -7-5-...