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Internal Use Only Website http://biz.lgservice.com 30” Freestanding Electric Range SERVICE MANUAL MODEL: LRE30757ST LRE30757SW LRE30757SB CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. January, 2008 P/NO : MFL37118302 Printed in Korea...
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.
GENERAL IMPOR ANT SAFETY INSTRUCTIONS IMPOR ANT SAFETY INSTRUCTIONS 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.
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GENERAL IMPOR ANT SAFETY INSTRUCTIONS IMPOR ANT SAFETY INSTRUCTIONS • Be sure your appliance is properly installed and grounded by a WARNING qualified technician. • Do not repair or replace any part of the appliance unless • DO NOT touch heating elements or specifically recommended in the manual.
GENERAL IMPOR ANT SAFETY INSTRUCTIONS IMPOR ANT SAFETY INSTRUCTIONS • Do Not Leave Children Alone - Children should not be left alone or SELF-CLEAN OVENS unattended in area where appliance is in use. They should never be • Do Not Clean Door Gasket – The door gasket is essential for a allowed to sit or stand on any part of the appliance.
GENERAL MODEL & SERIAL NUMBER LABEL MODEL & SERIAL NUMBER LABEL AND TECH SHEET LOCA TIONS AND TECH SHEET LOCA TIONS The Model/Serial Number label and Tech Sheet locations are shown below. Model & Serial Number Location Tech Sheet Location (On Low Rear Cover)
USING YOUR RANGE GENERAL INFORMA TION GENERAL INFORMA TION Convection Bake / Roast Mode Rating Label Upper element, lower element, Rear element(some Model numbers are recorded on the rating label. model) and fan operate during convection bake. Rating label is located on the lower front left corner Convection bake should be used for cooking of the oven frame.
USING YOUR RANGE CONTROL P ANEL FEA TURES CONTROL P ANEL FEA TURES single single Warming zone Left Rear element Right Rear element 11 12 13 14 15 16 single Dual Left Front element Right Front Dual element 1. BAKE PAD: Press to select the bake function. 11.
USING YOUR RANGE To turn on a single surface unit 4. TIMER ON/OFF (Right Rear, Left Rear, Left Front) TIMER Desired TIMER 1. Press ON/OFF pad for the desired element. ON/OFF time ON/OFF 2. Press ( ) pad to choose the desired setting. To cancel timer at any time, touch TIMER ON/OFF pad.
USING YOUR RANGE 5) BEEPER VOLUME 10. FAVORITES 1. Press OPTIONS pad 5 times FAVORITES START 2. Press “1” pad for loud level, : Once Bread “2” pad for normal level, : Twice Meat “3” pad for low level, : 3 times Chicken “4”...
USING YOUR RANGE ARMING DRA ARMING DRA To set the warming drawer control The rack can be used in 2 ways: 1. Press the ON/OFF pad at the • In the upright position to allow low profile food WARMING DRAWER items to be placed both under and on top of the position.
COMPONENT ACCESS This section instructs you on how to service each component inside the range. The components and their locations are shown below. COMPONENT LOCA TIONS COMPONENT LOCA TIONS Main PCB Cook Top Display PCB Cook Top Main PCB Door Locking Motor &...
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COMPONENT ACCESS REMOVING THE BACK, CONTROL COVER REMOVING THE BACK, CONTROL COVER AND KEY MEMBRANE, SUPPOR T ASSEMBL AND KEY MEMBRANE, SUPPOR T ASSEMBL 6. Remove 7 screws of KEY Membrane assembly and WARNING separate PCB assembly. • DISCONNET power supply cord from the outlet before servicing.
COMPONENT ACCESS REMOVING THE CONTROL POWER SUPPL REMOVING THE CONTROL POWER SUPPL AND POWER CONTROL BOARD (PCB) AND POWER CONTROL BOARD (PCB) 4. There are 3 PCB's (power control board). When WARNING you check PCB, check the proper pcb in default mode and check main pcb.
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COMPONENT ACCESS REMOVING THE SURF ACE ELEMENTS REMOVING THE SURF ACE ELEMENTS AND THE CERAMIC GLASS COOKT AND THE CERAMIC GLASS COOKT Step. 5 WARNING Protect the cooktop surface • DISCONNET power supply cord and turn the assembly over. from the outlet before servicing. •...
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COMPONENT ACCESS REMOVING THE DOOR LA TCH & DOOR SWITCH REMOVING THE DOOR LA TCH & DOOR SWITCH b) Remove the door latch from the burner box WARNING and unhook the actuating rod. • DISCONNET power supply cord from the outlet before servicing. •...
COMPONENT ACCESS REMOVING THE BROIL ELEMENT REMOVING THE BROIL ELEMENT b) Pull the element forward so that you can WARNING access the terminals and disconnect the wires. • DISCONNET power supply cord Terminals from the outlet before servicing. • Replace all panels and parts before operating.
COMPONENT ACCESS REMOVING THE HIDDEN BAKE ELEMENT REMOVING THE HIDDEN BAKE ELEMENT 1. Unplug range or disconnect power. 7. Bend the insulation glass fiber up. 2. Pull the range out of its mounting location so that you can access the rear of the unit. 3.
COMPONENT ACCESS REMOVING THE CONVECTION ELEMENT AN BLADE AND F AN MOT REMOVING THE CONVECTION ELEMENT AN BLADE AND F AN MOT 1. Disconnect power and remove oven racks. 7. To remove Fan blade, remove Nut by screwing clockwise. Fan blade can be replaced from inside 2.
COMPONENT ACCESS REMOVING THE OVEN LIGHT & SOCKET ASSEMBL REMOVING THE OVEN LIGHT & SOCKET ASSEMBL CAUTION WARNING • DISCONNET power supply cord • Be careful not to scratch or chip the from the outlet before servicing. oven liner paint when you remove •...
COMPONENT ACCESS REMOVING THE LA TCH DRIVE ASSEMBL REMOVING THE LA TCH DRIVE ASSEMBL DOOR LOCKING MECHANISM WARNING The door lock assembly is located at the back side • DISCONNET power supply cord of range. from the outlet before servicing. The structural elements are as below.
COMPONENT ACCESS REMOVING THE OVEN TEMPERA TURE SENSORS REMOVING THE OVEN TEMPERA TURE SENSORS 5. To remove an oven temperature sensor, WARNING disconnect the connector from the main harness and remove the two mounting screws in oven • DISCONNET power supply cord cavity.
COMPONENT ACCESS REMOVING THE W ARMING DRA WER ELEMENT REMOVING THE W ARMING DRA WER ELEMENT & TEMPERA TURE SENSOR & TEMPERA TURE SENSOR To remove the warming drawer element: WARNING 1. Remove the two bottom bracket screws • DISCONNET power supply cord from the outlet before servicing.
COMPONENT ACCESS REMOVING & REPLACING THE LIFT -OFF OVEN DOOR REMOVING & REPLACING THE LIFT -OFF OVEN DOOR To replace the door: CAUTION Step. 1 • Be careful when removing and Firmly grasp both lifting the door. sides of the door •...
COMPONENT ACCESS REMOVING THE OVEN DOOR HANDLE & GLASS REMOVING THE OVEN DOOR HANDLE & GLASS 5. Lift the liner assembly off the front glass and set WARNING it aside. 6. To remove the door handle & trim (for stainless model) •...
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COMPONENT ACCESS 7. To remove a hinge hanger assembly: d) Lift the inner oven door glass and bracket a) Remove the 2 top liner screws assembly out of the door liner. (See step 3 on page 3-14) b) Place the door liner assembly on a padded work surface with the hinge hangers over the edge.
COMPONENT ACCESS REMOVING THE OVEN DOOR GASKET REMOVING THE OVEN DOOR GASKET 3. Pull the ends of the gasket out of the liner holes. WARNING Liner Hole • DISCONNET power supply cord from the outlet before servicing. • Replace all panels and parts before operating.
COMPONENT ACCESS REMOVING A SIDE P ANEL REMOVING A SIDE P ANEL 7. Remove the two screws from the left or right side WARNING panel. • DISCONNET power supply cord from the outlet before servicing. • Replace all panels and parts before operating.
COMPONENT TEST Before testing any of 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. ALL units in the first few days of use should be checked for mis-wiring or loose connections 1.
Components Test procedures Results Normal: Approximately Door locking Motor 1. Refer to page 3-10 for the servicing procedure 2.6 kΩ ± 10% 2. Measure the resistance If not replace (Multiple meter scale: R x 1000) Abnormal: Infinite(open) below 5Ω (shorted) Door latch Door latch Micro Switch...
Components Test procedures Results Normal: Approximately Oven Sensor 1. Refer to page 3-11 for the servicing procedure 1.09 kΩ ± 10% 2. Measure the resistance after cooling down If not replace (Multiple meter scale: R x 1000) NOTE: Ω Value was tested at room temperature (77F/25˚C) NOTE: Oven sensor is so sensitive to temperature...
Components Test procedures Results Normal: Approximately Broil element 1. Refer to page 3-6 for the servicing procedure 14 Ω ± 10% 2. Measure the resistance after cooling down If not replace (Multiple meter scale: R x1) NOTE: Ω Value was tested at room temperature (77F/25˚C) Be careful the element is...
Components Test procedures Results Normal: Below 5 Ω. Oven lamp 1. Measure the resistance after cooling down If not replace (Multiple meter scale: R x1)
Components Test procedures Results Single surface units: 1. Refer to page 3-4 for the servicing procedure Left Front (LF), 2. Set the Multiple meter scale to the R x 1 Left Rear (LR) 3. Disconnect wires from cook-top elements 4. Touch the ohmmeter test leads to the element Right Rear(RR) terminal and 1A.
Components Test procedures Results Center Rear(CR) 1. Refer to page 3-4 for the servicing procedure Element 2. Set the Multiple meter scale to the R x 1 ;Warming Zone 3. Disconnect wires from CR elements 4. Touch the ohmmeter test leads to the element terminal and 1A.
Components Test procedures Results Dual surface element 1. Refer to page 3-4 for the servicing procedure : Right Front(RF) 2. Set the Multiple meter scale to the R x1 3. Disconnect wires from cook-top elements 4. Touch the ohmmeter test leads to the (E1 & 1A) and (E2 &...
COMPOSITION OF CONTROL Main PCB ( P/N : 6871W1N009E) Front Front Back Back Cook top display PCB ( P/N : 6871W1N010E) Controller assembly Front Back Cook top relay PCB ( P/N : 6871W1N011D) Key pad assembly Front Front Back Oven relay PCB ( P/N : EBR32401002) Back Front Back...
COMPOSITION OF CONTROL Main PCB Main PCB P/N : 6871W1N009E Main function Supply a DC power source (GND, -5V, -12V(Vry(oven heater switching)), -30V) Oven heater control (DLB / Broil / Bake / Warming drawer / convection) Oven display control Warming drawer display control Cook top heater control (Warmer zone / RR / LR / RF / LF) Cook top display control...
COMPOSITION OF CONTROL Cook-top display PCB Cook-top display PCB P/N : 6871W1N010E Main function Single radiant surface elements -Right Rear, Left Rear, Left Front- power level indication Dual radiant surface elements -Right Front inner, outer- power level indication Dual radiant surface element size indication -Right Front inner, outer Single radiant surface elements -warming zone (Center Rear) - power level indication...
COMPOSITION OF CONTROL Cook-top relay PCB Cook-top relay PCB P/N : 6871W1N011D Main function Supply a DC power source (GND, -12V (Vry(cooktop heater switching voltage)) Single Radiant Surface Elements -Right Rear, Left Rear, Left Front - on/off, power level relay switching Dual Radiant Surface Elements -Right Front INNER, OUTER - on/off, power level relay switching Single Radiant Surface Elements - Warming Zone (Center Rear) -on/off, power level relay switching...
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CHECKING FLOW CHART BY FAILURE MODE No display (No power) Blank display Enter key input Check the thermal fuse Some beep (See the page 3-1) sound? Check AC input voltage of Main PCB Cook-top display -Main PCB CN2 (pin 1 and 3) blank? (Go to page 6-4) Check voltage –...
FAILURE MODE FLOW CHART No display (No power) Blank display Enter key input Check the thermal fuse Some beep (See the page 3-1) sound? Check AC input voltage of Main PCB Warming drawer display blank? -Main PCB CN2 (pin 1 and 3) (Go to page 6-4) Check voltage –...
FAILURE MODE FLOW CHART No display (No power) Blank display Enter key input Check the thermal fuse Some beep (See the page 3-1) sound? Check AC input voltage of Main PCB Oven display blank? -Main PCB CN2 (pin 1 and 3) (Go to page 6-4) Replace the main PCB(009E)
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FAILURE MODE FLOW CHART No display (No power) Check the harness of between L1~N Is it 120V AC? Normal? Disconnect power Replace the defective harness Check the power transformer (Refer to the below) Primary S3 S2 S1 Secondary Fig.1 Side Lead Color DCR(Ω) black ~ white...
FAILURE MODE FLOW CHART Oven does not heat Code Error mode Operation Times/sampling No heating If current oven temperature does not exceed 150˚F and During cook less than start temperature over 5 minutes on preheating, where door is closed. (except proof and cook & warm ) No Heating(Main Oven) Disconnect power Check for loose connections at bake, broil,...
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FAILURE MODE FLOW CHART Oven does not heat Normal? Replace the bake heater Check the broil heater (measure the resistance after cooling down) Normal: approximately 14Ω Normal? Replace the broil heater Check the convection heater (measure the resistance after cooling down) Normal: approximately 17Ω...
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FAILURE MODE FLOW CHART Oven does not heat Check for loose oven sensor connector Normal? Reconnect Check the oven sensor (measure the resistance after cooling down) Normal: approximately 1.09kΩ Normal? Replace the oven sensor Replace the oven relay PCB (02) Normal? Replace the main PCB(009E) For further check of main PCB...
FAILURE MODE FLOW CHART Cook-top does not heat No heating (All or a part of cook-top heaters) Disconnect power Check for loose connection at board (011B PCB) to cook top heaters. Normal? Reconnect. If defective harness, replace or fix Check for loose connector (main PCB(009E) CN9 and CN16) Continued on the next page...
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FAILURE MODE FLOW CHART Cook-top does not heat Normal? Reconnect. Remove the cook-top relay PCB(011D) harness and pull the cook-top relay PCB(011D) forward from the PCB case Inspect the cook-top relay PCB(011D) Wide pattern(Live part) blown out pin to pin short or connector harness damaged Repairable Normal? by yourself?
FAILURE MODE FLOW CHART Oven lamp does not operate Oven lamp does not operate Disconnect power Check for loose connection of oven lamp terminal and harness Normal? Reconnect Check for loose connector (main PCB CN1) If defective harness, replace or fix Normal? Reconnect Check the oven lamp (measure the resistance)
FAILURE MODE FLOW CHART No key input Key does not input Reconnect the main PCB connector CN11 and CN20 more than two times Normal? Some keys or All keys? Some Replace the main PCB(009E) Replace the main PCB Normal? Replace the keypad assembly 6-11...
FAILURE CODES DISPLAY CAUSE CORRECTIVE ACTION WARNING SHOWS Warming A. Perform step 1 through 2 above • DISCONNET power supply cord from drawer B. Open the back panel and check continuity Sensor of the sensor and Control (PCB) the outlet before servicing. shorted C.
F-CODE FLOW CHART Key short error F-1 error Code Error mode Operation Times/sampling Key shorted If a key pad is continuously short for 60 seconds. Key short error (F-1) Plugged out the power, remove keypad-tail and check F-1 error recur or not, after plugging in the power recur? Disconnect power...
F-CODE FLOW CHART Door lock system error F-2 error Code Error mode Operation Times/sampling Door Lock Fail In case of Door Lock Failure 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-2 error code appears.
F-CODE FLOW CHART Door lock system error F-2 error Normal? Replace the micro switch Check the door locking motor (measure the resistance) normal: approximately 2.6kΩ abnormal: infinite or below 5 Ω Normal? Replace the door locking motor Check for loose connector (Front) (main PCB CN4) Front Normal? Reconnect...
F-CODE FLOW CHART Door lock system error F-2 error Inspect connector pin solder of CN4 (Back) (main PCB CN4) Back If pin solder is cracked, repair and re-use Cracked? Replace Repair and fix...
F-CODE FLOW CHART Main oven sensing error F-3, F-4 error Code Error mode Operation Times/sampling Opened Sensor Oven Thermistor remains open for over During cook 1 min, after cook starts Shorted Sensor Oven Thermistor is short for over 1 min During cook after cook starts Main oven sensing failed...
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F-CODE FLOW CHART Main oven sensing error F-3, F-4 error Check for loose connector. (Front) (main PCB CN6) Check for loose connector. (main PCB CN6) and look for harness terminals damaged or not Reconnect and Normal? replace the bad harness Remove the main PCB (009E) harness and pull the PCB (009E) forward from the PCB case Inspect connector pin solder of CN6 (Back) (main PCB CN6)
F-CODE FLOW CHART Warming drawer sensing error F-6 error Code Error mode Operation Times/sampling Opened Sensor Warm Drawer Thermistor open Over 1 min after warm During operate drawer operates Warming drawer sensing failed Disconnect power Check for loose warming drawer sensor connector.
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F-CODE FLOW CHART Oven too hot error F-9 error Code Error mode Operation Times/sampling Oven hot Oven temperature is over 650˚F During cook continuously during 2 minutes on cooking. (Not self clean mode) Oven is too hot (F-9) Disconnect power / Remove the oven relay PCB (02) harness and pull the oven relay PCB (02) forward from case Check for a welded bake relay.
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F-CODE FLOW CHART Oven too hot error F-9 error Check for a welded broil relay. (measure the resistance) Welded Normal Continuity Infinite Normal? Replace the oven relay PCB(02) Replace the main relay PCB(009E)
TROUBLE SHOOTING PROBLEMS POSSIBLE CAUSES & FAULTS SOLUTIONS Oven not operating. • Bad power control board (PCB) • Test and/or replace PCB ➞ Refer to the page 6-1~6-4 • Power outage • Verify power is present at unit. • Verify that the circuit breaker is not tripped •...
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TROUBLE SHOOTING PROBLEMS POSSIBLE CAUSES & FAULTS SOLUTIONS Electronic timer will not • Failed main power control board • Replace power control board(PCB) accept Programming. Electronic timer will not • Failed main power control board • Replace power control board(PCB) accept Programming.
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TROUBLE SHOOTING PROBLEMS POSSIBLE CAUSES & FAULTS SOLUTIONS Oven door sagging on one • Hinge loose or out of position to • Adjust hinges or replace hinges side oven liner Door does not close • Broken or misadjusted door spring •...
SCHEMATIC DIAGRAM NOTE:Schematic diagram shows door WARNING switch In the cook position with the oven POWER MUST BE door open and elements off. DISCONNECTED BEFORE SERVICING THE APPLIANCE RADIANT COOK-TOP Wattage RR:1200W LR:1200W LF:2500W RF(Right Front) :1700W(inner) :2700W(Dual) CR:100W WIRE COLORS SYMBOL COLOR WHITE...
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. For Model: LRE30757ST / LRE30757SW / LRE30757SB BAKE / COOK & WARM / PROOF...