GE JT930 Service Manual

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30″ ELECTRIC TRIVECTION™ WALL OVENIMPORTANT SAFETY NOTICE: This information is intended for use byindividuals possessing adequate backgrounds of electrical, electronic andmechanical experience. Any attempt to repair any major appliance mayresult in personal injury and property damage. Neither the manufacturer northe seller can be responsible for the interpretation of this information orassume any liability in connection with its use. THIS BOOKLET PROVIDESBASIC INFORMATION INTENDED TO ASSIST A KNOWLEDGEABLETECHNICIAN IN TROUBLESHOOTING PROBLEMS WITH THE OVEN. FORDETAILED INFORMATION ON SERVICING THIS OVEN, REFER TO SERVICEGUIDE 31-3115.DISCONNECT POWER BEFORE SERVICINGIMPORTANT: RECONNECT ALL GROUNDING DEVICES. All parts of thisappliance capable of conducting electrical current are grounded. Ifgrounding wires, screws, straps, clips, nuts or washers used to complete apath to ground are removed for service, they must be returned to theiroriginal position and properly fastened.PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TOAVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY.A. A MICROWAVE EMISSION CHECK SHOULD BE PERFORMED PRIOR TOSERVICING IF THE OVEN IS OPERATIVE.B. DO NOT OPERATE OR ALLOW THE OVEN TO BE OPERATED WITH THEDOOR OPEN.C. IF THE OVEN OPERATES WITH THE DOOR OPEN:1. INSTRUCT THE USER NOT TO OPERATE THE OVEN.2. CONTACT THE MANUFACTURER AND THE CENTER FOR DEVICESAND RADIOLOGICAL HEALTH IMMEDIATELY.D. MAKE THE FOLLOWING SAFETY CHECKS ON ALL OVENS TO BESERVICED BEFORE ACTIVATING THE MAGNETRON OR OTHERMICROWAVE SOURCE, AND MAKE REPAIRS AS NECESSARY:1. INTERLOCK OPERATION2. PROPER DOOR CLOSING3. SEAL AND SEALING SURFACES (ARCING, WEAR AND OTHERDAMAGE)4. DAMAGE TO OR LOOSENING OF HINGES AND LATCHES5. EVIDENCE OF DROPPING OR ABUSEE. BEFORE TURNING ON MICROWAVE POWER FOR ANY TEST ORINSPECTION WITHIN THE MICROWAVE GENERATINGCOMPARTMENTS, CHECK THE MAGNETRON, WAVE GUIDE ORTRANSMISSION LINE AND CAVITY FOR PROPER ALIGNMENT,INTEGRITY AND CONNECTIONS.F. ANY DEFECTIVE OR MISADJUSTED COMPONENTS IN THE INTERLOCKMONITOR, DOOR SEAL AND MICROWAVE GENERATION ANDTRANSMISSION SYSTEMS SHALL BE REPAIRED, REPLACED ORADJUSTED BY PROCEDURE DESCRIBED IN THIS MANUAL BEFORETHE OVEN IS RELEASED TO THE OWNER.G. A MICROWAVE LEAKAGE CHECK TO VERIFY COMPLIANCE WITH THEFEDERAL PERFORMANCE STANDARD SHOULD BE PERFORMED ONEACH OVEN PRIOR TO RELEASE TO THE OWNER.GROUNDING SPECIFICATIONSGround Path Resistance 0.10 Ω Max.Insulation Resistance 250 KΩ Min.INSTALLATION POWER REQUIREMENTSPower Supply: This appliance must be be supplied with proper voltage andfrequency and connected to an individual, properly grounded branch circuitbreaker or time-delay fuse as noted on the rating plate. Wiring must conform to theNational Electrical Code. The rating plate is located on the lower front framebehind the oven door.CAUTION: This oven power supply cable is recognized for copper wire only,NOT ALUMINUM WIRE. Refer to the Installation Instructions for additional details.OVERCURRENT PROTECTION—WALL-MOUNTED OVENNEC FUSE MAXIMUM KILOWATT RATINGRATING 208V 236V 240V20 Amp 4.2 4.7 4.830 Amp 6.2 7.1 7.235 Amp 7.3 8.3 8.440 Amp 8.3 9.4 9.650 Amp 10.4 11.8 12.0SERVICE MODEThis electronic control features a service mode to help diagnose a problem causedby a particular load. To enter Service Mode, disconnect main power to the oven forat least 15 seconds. Reconnect power and enter ‘0803’ on the keypanel within 5minutes after the control initializes. Select SERVICE from the SPECIAL MODESmenu. *SERVICE MODE* menu appears. Navigate through SERVICE MODEmenu by pressing the pads next to the NEXT and BACK keys. Availabletroubleshooting modes are:• COOKING LOADS (Verify proper operation of cooking elements, microwave andconvection fan. See troubleshooting section below.)• DOOR LATCH (Verify proper operation of door lock motor and switches)• DOOR POSITION (Verify proper operation of door sense switch)• RTD (Displays oven sensor temperature in red on right display)• VENT FAN (Verify proper operation of ventilation fan)• R COOLING FAN (Verify proper operation of cooling fan)• L COOLING FANS (Verify proper operation of mag cooling fan, HVT fanand mag stirrer fan)• OVEN LIGHT (Verify proper operation of oven lights)• OFFSET (Oven calibration offset in non-microwave modes)• DISPLAY (Verify operation of display segments by allowing all of them to beturned on and off. Press CLEAR/OFF key to return display to normal)• KEYS (Verify proper operation of keypanel)• LINE VOLT(AGE) (Displays line voltage L1-L2 in the upper temperature display)• F CODES (Displays up to last 7 ERC Failure Codes)NOTE: Always check failure codes and then clear them.• COSENSOR (KENMORE ONLY)Press EXIT to return to normal cooking mode.ACRONYM TABLECAP = capacitorCOM = commonCO Sensor (on some models) = carbon monoxide sensorsfor Sens-a-Clean (on some models)ERC = engineering range controlF codes = ERC failure codesHVT = high voltage transformerJ = jumper/connector on a PCBK = relay on a PCBMAG = magnetronMLB = main logic boardMPB = main power boardMW = microwaveNC = normally closedNO = normally openedPCB = printed circuit board such as MLB or MPBRTD = resistive thermal device (oven temperature sensor)TCO = thermal cutoutTROUBLESHOOTING COOKING LOADS IN SERVICE MODECAUTION: TO PREVENT ELECTRICAL SHOCK, USE EXTREME CAUTIONWHEN DIAGNOSING OVEN WITH OUTER COVERS REMOVED AND POWER“ON”. THE HIGH VOLTAGE CIRCUIT OF THE MAGNETRON POWERSECTION (HVT, CAPACITOR, DIODE, MAGNETRON) IS 4400 VOLTSPOTENTIAL WITH RESPECT TO GROUND.WAIT AT LEAST 5 MINUTES AFTER POWERING DOWN BEFORESERVICING THE MAGNETRON POWER SECTION.CAUTION: HEATSINKS ON MAIN POWER BOARD ARE ELECTRICALLYLIVE. TAKE SPECIAL PRECAUTIONS WHEN TROUBLESHOOTING THEMAIN POWER BOARD WITH POWER “ON”. WAIT AT LEAST 5 MINUTESAFTER POWERING DOWN BEFORE SERVICING THE MAIN POWER BOARD.Cooking loads (bake, broil, convection elements and convection fan) can beenergized individually through SERVICE MODE (Press key next to COOKINGLOADS, then appropriate load.) When the appropriate load is turned on inSERVICE MODE, first verify that the element is heating or the fan is turning.If load is not energized, check AC relay voltages according to the second columnin the following table:SERVICE MODE (CONT.)RELAY CONTROL TABLENote: To turn off all loads that are energized in COOKING LOADS, press theCLEAR/OFF key or exit the COOKING LOADS menu. If load is not turned off,additional loads can be turned on at the same time.If AC voltage measures OK, then check the load (element, fan, lock motor, HVT, etc.)and/or wiring to the load and repair/replace as required. If there is no AC voltagesupplied to the load through the power relays per the wiring schematic, then checkthe DC power supply voltages from the Main Power Board (MPB-J3 connector) tothe Main Logic Board (MLB-J5 connector) according to the following table:If voltages do not measure according to the table above, replace Main PowerBoard. If voltages measure OK, then measure DC voltages according to theprevious relay control table (relay control signals columns 3, 4 and 5). If the MLB-J3 pins do not provide the correct DC voltages, then replace the Main Logic Board.SERVICE MODE (CONT.)If display is blank, oven light does not operate when the oven door is opened andkeypanel does not respond, first check DC power supply voltages. Next, check DCvoltages at MLB J2: J2-2, J2-4, J2-6, J2-8 should be +12VDC. If not, replace TextDisplay and/or Time/Temp Display.If DC power supply voltages are OK:If display is blank and keyboard is not responding, replace MLB.If just the display is blank, replace the display.If just the keyboard is not responding, check glass touch display. If OK, replace MLB.If oven light does not turn on when door is opened, check oven light relay perrelay troubleshooting table. If relay voltages are OK, check door sense switch perDOOR SWITCH section.MICROWAVEa. Microwave Leakage TestPlace 275mL of water in a 600mL beaker.Place beaker in center of oven shelf.Set meter to 2450Hz scale.Enter SERVICE MODE, press COOKINGLOADS, then MW.Time for 5 minute test.Hold probe perpendicular to surface being tested and scan surface at rateof one inch/sec.Test following areas:Entire perimeter of door and control panel.Viewing surface of door window.Exhaust vents.Maximum leakage not to exceed 4 mW/cm2.Record Data on service invoice and microwave leakage report.NOTE: Maximum allowable leakage is 5 mW/cm2. 4 mW/cm 2 is used toallow for measurement and meter accuracy. Inform manufacturer of anyoven found to have emissions in excess of 5 mW/cm2. Make repairs tobring the unit into compliance at no cost to the owner and try to determinecause. Instruct owner not to use oven until it has been brought into compliance.b. Performance TestingStandard test load will be 1 liter (1000mL) of water with an initialtemperature 59° ~ 75°F in a 1000mL beaker (PN WB64X73).Record initial water temperature.Place beaker in center of middle oven shelf.Enter SERVICE MODE, press COOKINGLOADS, then MW.Time for 2 minutes, then open door.Record end water temperature.The difference between the initial and ending temperature should be 12°Fminimum at 240VAC.NOTE: Standard sparkle blocks are not applicable for testing of themicrowave assist mode in this oven.c. High-Voltage CapacitorWARNING: The capacitor holds its 4400V charge for at least 2 minutesafter power is removed. Always be certain that the capacitor is dischargedbefore servicing. Mechanically discharge by placing an insulated handlescrewdriver between the diode connection of the capacitor and ovenchassis ground.d. MagnetronThe magnetron cannot be serviced from the component compartment;the unit must be removed from the wall. Be sure to replace the groundwire under the screw head when installing. Make sure that the magnetronis seated flat against the mounting surface.e. Special assembly noteElements, convection fan and oven light contain special radiation screensand chokes. Be sure to replace these in the oven cavity. Take special carenot to strip any screws when replacing these components.229C4059P444-1The branch circuit load for onewall-mounted oven or onecounter-mounted cooktop is therating on the nameplate of theappliance. The branch circuitload for a counter-mountedcooktop and not more thantwo wall-mounted ovens – allsupplied from a single branchcircuit and located in the sameroom – shall be computed byadding the nameplate ratings ofthe individual appliances andtreating this total as equivalentto one range.MPB MLB Signal Name Min MaxJ3-1 J5-1 +12Vdc 11.00Vdc 12.75VdcJ3-2 J5-2 12Vdc, 5Vdc Ground — —J3-3 J5-3 +5Vdc 4.7Vdc 5.3VdcJ3-4 J5-4 12Vdc, 5Vdc Ground — —J3-5 J5-5 -14Vdc -14.75Vdc -12.75VdcJ3-6 J5-6 Not Connected —J3-7 J5-7 L1 thru 2Mohm/.47 uF cap on MPBJ3-8 J5-8 L1 thru 2Mohm/.47 uF cap on MPBJ3-9 J5-9 Not Connected —J3-10 J5-10 NT thru 2Mohm/.47 uF cap on MPBJ3-11 J5-11 Not Connected —J3-12 J5-12 L2 thru 2Mohm/.47 uF cap on MPB120VAC line monitor240VAC line monitor240VAC line monitor120VAC line monitorCONTROLS DC POWER SUPPLY VOLTAGE TABLEAC VOLTAGESSERVICE MODEFunctionMain Pwr Board RelayON=120VAC (L1-N or L2-N)or 240VAC (L1-L2)OFF=0VRelay ControlON = 0VdcOFF = 12VdcRelay ControlON = 4.6VdcOFF = -14Vdc *Enable = 4.2VdcDisable = -14.0Vdc NotesL2 = J4-8 (K1-NO) MPB J1-10MLB J3-10N = J103L2 = J4-7 (K5-NO) MPB J1-9MLB J3-9N = J103L1 = J4-5 (K13-NO) MPB J1-4MLB J3-4N = J103HVT T2 = L2 = J107 (K9-NO)ORHVT T3 = L2 = J105 (K9-NC)MPB J1-17MLB J3-17ORMPB J1-17 OFFMLB J3-17 OFFMPB J1-1MLB J3-1HVT T1 = L1 = J114L2 = J4-9 (K106-NO) MPB J1-3MLB J3-3N = J103L1 = K10-NO MPB J1-8MLB J3-8MPB J1-1MLB J3-1L2 = K102-NO (DLB) MPB J1-12MLB J3-12L1 = J4-2 (K105-NC) MPB J1-16 OFFMLB J3-16 OFFN = J103L1 = J4-3 (K105-NO) MPB J1-16MLB J3-16N = J103L1 = K7-NO MPB J1-6MLB J3-6MPB J1-1MLB J3-1L2 = K11-COM (DLB) MPB J1-11MLB J3-11L1 = K8-NO MPB J1-7MLB J3-7MPB J1-1MLB J3-1L2 = K11-COM (DLB) MPB J1-11MLB J3-11L1 = J113 (K103-NO) MPB J1-18MLB J3-18MPB J1-1MLB J3-1L2 = K11-COM (DLB) MPB J1-11MLB J3-11L1 = J4-1 (K2-COM) MPB J1-14MLB J3-14N = J103Note: Ground reference for dc voltage measurements MPB = Main Power Board * OFF = 0Vdc if Disable = -14Vdcis J3-2 or J3-4 on MPB MLB = Main Logic Boardor J5-2 or J5-4 on MLBRight Cooling FanR CoolingFan -> On/OffLeft Cooling FansMag StirrerMag FanHVT FanL CoolingFans -> On/OffFan comes on when entering thecooking loads menu.Oven LightOvenlight -> On/OffMicrowaveCookingLoads -> MWK6 (Mag Main Relay) must be energizedMPB J1-5 ON (4.6Vdc)MLB J3-5 ON (4.6Vdc)Note: MagTap is automatically selectedby Line VoltageDoor LatchDoorLatch -> Lock/UnlockBroil element must be turned offBake ElementCookingLoads -> BakeBake2 ElementCookingLoads -> Bake2Broil ElementCookingLoads -> BroilBroil element must be turned offDC VOLTAGESK4 (Convection Fan Relay) must beenergizedMPB J1-15 ON (0Vdc)MLB J3-15 ON (0Vdc)Convection FanCounter ClockwiseCookingLoads-> ConvFan -> CCWConvection FanClockwiseCookingLoads-> ConvFan -> CWVent FanVentFan -> On/OffK4 (Convection Fan Relay) must beenergizedMPB J1-15 ON (0Vdc)MLB J3-15 ON (0Vdc)Convection ElementCookingLoads -> ConvElemFan comes on when entering thecooking loads menu.Fan comes on when entering thecooking loads menu.

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