MICROWAVE OVEN CE745GR SERVICE Manual CONTENTS MICROWAVE OVEN 1. Precaution 2. Specifications 3. Operating Instructions 4. Disassembly and Reassembly 5. Alignment and Adjustments Auto l b s. kg Auto oz. g 1-2-3 h 10min min 1min 10s. 6. Troubleshooting 1min+ GRILL CE745GR 7. Exploded Views and Parts List 8. PCB Diagrams 9.
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY (a) Do not operate or allow the oven to be operated with the door open.
1. Precaution Follow these special safety precautions. Although the microwave oven is completely safe during ordinary use, repair work can be extremely hazardous due to possible exposure to microwave radiation, as well as potentially lethal high voltages and currents. 1-1 Safety precautions ( ) 1. All repairs should be done in accordance with the procedures described in this manual. This product complies with Federal Performance Standard 21 CFR Subchapter J (DHHS). 2.
Pretaution 1-2 Special Servicing Precautions (Continued) 16. When checking the continuity of the witches or transformer, always make sure that the power is OFF, and one of the lead wires is disconnected. 17. Components that are critical for safety are indicated in the circuit diagram by shading, or . 18. Use replacement components that have the same ratings, especially for flame resistance and dielectric strength specifications.
2. Specifications 2-1 Table of Specifications MODEL ITEM CE745GR TIMER 99 MINUTES 90 SECONDS POWER SOURCE 230V/50HZ, AC POWER CONSUMPTION MICROWAVE : 1,400W,GRILL : 1100W OUTPUT POWER FROM85 TO 850W (10 LEVEL POWER) (IEC-705 TEST PROCEDURE) OPERATING FREQUENCY 2,450MHz MAGNETRON OM75PH(31) COOLING METHOD COOLING FAN MOTOR OUTSIDE DIMENSIONS 191/4"(W) x 1027/32"(H) x 143/8"(D) NET WEIGHT 36.3 LBS. SHIPPING WEIGHT 39.6 LBS.
3. Operating Instructions 3-1 Control Panel Instant Cook Button Auto Defrost Butten Auto Auto Cook Button Auto Kg,g Button More/Less Button oz. g lbs. kg Clock Setting Button Power Level Selection Button Grill Button Hold/Timer Button Combi Button 1-2-3 h 10min Memory Button min 1min 10s.
4. Disassembly and Reassembly 4-1 Replacement of Magnetron, Motor Assembly and Lamp Remove the magnetron including the shield case, permanent magnet, choke coils and 500pF capacitors (all of which are contained in one assembly). Cover Air Lamp Thermo S/W 1. Disconnect all lead wires from the magnetron Fan Motor and lamp. BKT-Mountain 2. Remove the bracket mounting. 3. Remove the air cover. 4. Remove screws securing the magnetron to the wave guide. 5. Take out the magnetron very carefully. 6.
Disassembly and Reassembly 4-3 Replacement of Door Assembly 4-3-1 Removal of Door Assembly Remove screws securing the upper hinge and lower hinge. Then remove the door assembly. Upper Hinge Screw Lower Hinge Screw 4-3-2 Removal of Door "C" Insert flat screwdriver into the gap between Door "A" and Door "C" to remove Door "C". Be careful when handling Door "C" because it is fragile.
Disassembly and Reassembly 4-3-4 Removal of Key Door & Spring 1. Remove pin hinge from Door "E" Detach spring from Door "E" and key door. Door "E" 2. After replacement of the defective component parts of the door, reassemble it and follow the instructions below for proper installation and adjustment so as to prevent an excessive microwave leakage. 3.
Disassembly and Reassembly 4-6 Replacement of Control Circuit Board 4-6-1 Removal of Control Box Assembly 1. Be sure to ground any static electric charge in your body and never touch the control circuit. 2. Disconnect the connectors from the control circuit board. Screw 3. Remove screws securing the control box assembly. 4. Remove the screw securing the ground tail of the keyboard. Control Box 4-6-2 Removal of P.C.B Assembly 1.
5. Alignment and Adjustments PRECAUTION 1. High voltage is present at the high voltage terminals during any cook cycle. 2. It is neither necessary nor advisable to attempt measurement of the high voltage. 3. Before touching any oven components or wiring, always unplug the oven from its power source and discharge the high voltage capacitor. 5-1 High Voltage Transformer 1. Remove connectors from the transformer terminals and check continuity. 2.
Alignment and Adjustments 5-4 High Voltage Capacitor 1. Check continuity of the capacitor with the meter set at the highest resistance scale. 2. Once the capacitor is charged, a normal capacitor shows continuity for a short time, and then indicates 9MΩ. 3. A shorted capacitor will show continuous continuity. 4. An open capacitor will show constant 9MΩ. 5. Resistance between each terminal and chassis should read infinite. 5-5 High Voltage Diode 1.
Alignment and Adjustments 5-8 Output Power of Magnetron CAUTION MICROWAVE RADIATION PERSONNEL SHOULD NOT ALLOW EXPOSURE TO MICROWAVE RADIATION FROM MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY. The output power of the magnetron can be measured by performing a water temperature rise test. Equipment needed : * Two 1-liter cylindrical borosilicate glass vessel (Outside diameter 190 mm) * One glass thermometer with mercury column NOTE: Check line voltage under load.
Alignment and Adjustments 5-10 Microwave Heat Distribution - Heat Evenness The microwave heat distribution can be checked indirectly by measuring the water temperature rise at certain positions in the oven: 1. Prepare five beakers made of 'Pyrex', having 100 milliliters capacity each. 2. Measure exactly 100milliliters off water load with a measuring cylinder, and pour into each beaker. 3. Measure the temperature of each water load. (Readings shall be taken to the first place of decimals.) 4.
6. Troubleshooting PRECAUTION 1. CHECK GROUNDING BEFORE CHECKING FOR TROUBLE. 2. BE CAREFUL OF THE HIGH VOLTAGE CIRCUIT. 3. DISCHARGE THE HIGH VOLTAGE CAPACITOR. 4. WHEN CHECKING THE CONTINUITY OF THE SWITCHES OR TRANSFORMER, DISCONNECT ONE LEAD WIRE FROM THESE PARTS AND THEN CHECK CONTINUITY WITHOUT THE POWER SOURCE ON. TO DO OTHERWISE MAY RESULT IN A FALSE READING OR DAMAGE TO YOUR METER. 5. DO NOT TOUCH ANY PART OF THE CIRCUIT OR THE CONTROL CIRCUIT BOARD, SINCE STATIC DISCHARGE MAY DAMAGE IT.
Troubleshooting 6-1 Electrical Malfunction(continued) SYMPTOM CAUSE CORRECTIONS Oven lamp and fan motor turn on 1. Misadjustment or loose wiring of primary latch switch 2. Defective primary latch switch Adjust door and latch switches. Oven can program but timer does not start. 1. Open or loose wiring of secondary interlock switch 2. Off-alignment of primary interlock 3. Defective secondary interlock S/W Adjust door and interlock switches. Microwave output is low;.
7.
Exploded Views and Parts List 7-2 Main Parts List Ref. No. Parts No.
Exploded Views and Parts List 7-3 Door Parts List Ref. No. Parts No. Description/Specification Q'ty D 1 DE64-40007A DOOR-A;ABS(VH-080) T3.0 WHT 1 D 2 DE64-40006A DOOR-KEY;POM(TC3005) T2.0 12GR BLK CE9 1 D 3 DE61-70033A SPRING-KEY;ES HSWR10 PI0.6 D6.0 L22.3 BL 1 D 4 DE67-20004D SCREEN-DOOR;PC T1.5 W173.6 L373.5 WHT CE 1 D 5 DE92-50126B ASSY DOOR-E;COATING BLK CE745G 1 D 6 DE64-40008B DOOR-C;PP T1.5 W L G BLK CE745G 1 D 7 DE01-00003B FILM-DOOR;PC T0.
Exploded Views and Parts List 7-6 Standard Parts List Parts No.
8. P.C.B Diagrams 8-1 P.C.
P.C.B Diagrams 8-2 P.C.B Parts List Parts No. 8-2 Description / Specification Q'ty Remarks 0401-001002 DIODE-SWITCHING;1N4148M,100V,200mA,500mW 16 D5~20 0402-000559 DIODE-RECTIFIER;D4G,400V,1A,T-1 3 D01,2,4 0501-000283 TR-SMALL SIGNAL;KSA539-Y,PNP,400mW,TO-92 1 TR01 0501-000388 TR-SMALL SIGNAL;KSC815-Y,NPN,400mW,TO-92 1 TR03 2001-000003 R-CARBON;330ohm,5%,1/8W,AA,TP,1.8x3.2mm 2 R03,04 2001-000037 R-CARBON(S);330ohm,5%,1/2W,AA,TP,2.4x6.
9. Schematic Diagrams 9-1 Schematic Diagrams MGT TCO ASSY CHOKE P.C.B H.V.TRANS PRIMARYS/W BLK BLK BLK BLK COM C3 FUSE BLU BLK 230V40W L LAMP WHT 1ND GRILL RELAY F-MOTOR L.V.TRANS YEL MAIN RELAY WHT RESISTOR C1 HEATER YEL 21V DM FM H.V.FUSE (0.75A-CE745G/ 0.8A-CE945G) COM NC 0V NO H.V.CAPACITOR ORG WHT BLK INRUSH RELAY BLK MONITOR FUSE (250V1.6A) C2 CAVITY TCO BLU H.V.
