R662 SERVICE MANUAL MICROWAVE OVEN MODEL R-662(W)M R-662(SL)M R-662(K)M (800W 240V 50Hz) In interests of user-safety the oven should be restored to its original condition and only parts identical to those specified should be used. CONTENTS CHAPTER 1. SAFTY PRECAUTIONS CHAPTER 9. MEASUREMENT OF MICROWAVE POWER OUTPUT CHAPTER 2. CAUTIONS CHAPTER 10. TROUBLE SHOOTING PROCEDURES CHAPTER 3. THE HEATING PRINCIPLE OF MICROCHAPTER 11. COMMON BREAKDOWN AND MEANS OF WAVE PREPARING CHAPTER 4.
SAFETY PRECAUTIONS This device is to be serviced only by properly qualified service personnel. Consult the service manual for proper service procedures to assure continued safety operation and for precautions to be taken to avoid possible exposure to excessive microwave energy. 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.
TABLE OF CONTENTS （page） SAFETY PRECAUTIONS---------------------------------------------------------Inside front cover CAUTIONS------------------------------------------------------------------------------------------------1-1 THE HEATING PRINCIPLE OF MICROWAVE--------------------------------------------------2-1 INSTALLATIONS----------------------------------------------------------------------------------------3-1 OPERATING INSTRUCTIONS----------------------------------------------------------------------
CAUTIONS Unlike other appliances, the microwave oven is high-voltage and high-current equipment. Though it is free from danger in ordinary use, extreme care should be taken during repair. MICROWAVE RADIATION Personnel should not be exposed to the microwave energy which may radiate from the magnetron or other microwave generating device if it is improperly used or connection. • DO NOT operate on a 2-wire extension cord during All input and output microwave connections, repair and use.
THE HEATING PRINCIPLE OF MICROWAVE Microwave is one kind of radio wave whose wave length is very short, frequency is very high. Therefore, it is called ultrahigh frequency electromagnetic wave. Microwave can heat food mainly result in the mutual affect of the food in the microwave field and microwave field itself.
INSTALLATIONS BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY INSTALLING EARTHING INSTRUCTIONS 1. Empty the microwave oven and clean inside it with a soft, damp cloth. Check for damage such as This microwave oven is designed to be used in a fully misaligned door, damage around the door or dents earthed condition. inside the cavity or on the exterior. It is imperative, therefore, to make sure it is properly earthed before servicing 2.
SCHEMATIC DIAGRAM
CIRCUIT DESCRIPTION As the door is closed, the contact of MONITOR • 3.2 volts AC is generated from the filament winding of SWITCH opens. This switch creates the short circuit to the high voltage transformer. This 3.2 volts is applied blow fuse during operation under abnormal condition. to the magnetron to heat the magnetron filament (ie, should the contacts of primary and secondary through two noise-preventing choke coils.
SERVICE INFORMATION TOOLS AND MEASURING INSTRUMENTS NECESSARY TOOLS Tools normally used for TV servicing are sufficient. NECESSARY MEASURING INSTRUMENTS Standard tools are listed below. • TESTER(VOLTS-DC, AC.
MEASUREMENT WITH OUTER CASE REMOVED NOTES WHEN MEASURING • When you replace the magnetron, measure for • The test probe must be removed no faster than microwave energy leakage before the outer case is 1 inch/sec (2.5 cm/sec) along the shaded area, installed and after all necessary components are otherwise a false reading may result. replaced or adjusted. • The test probe must be held with the grip portion of Special care should be taken in measuring the the following parts. handle.
MEASUREMENT OF MICROWAVE POWER OUTPUT • Microwave power output measurement is made with the microwave oven supplied at its rated voltage and operated at its maximum microwave power setting with a load of (1000±5) g of potable water. • The water is contained in a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of approximately 190mm. • The oven and the empty vessel are at ambient temperature prior to the start of the test.
TROUBLE SHOOTING PROCEDURES Before overhauling a microwave oven, you should judge the breakdown and the cause correctly, then you can repair it with corresponding ways. The overhauling must be proceed in order, any hasty conclusion is not recommendable, otherwise overworking would be done when repair. The microwave oven may occur compound breakdown due to all kinds of different reasons, thus, when overhaul, they all should be taken into consideration.
4. Examine when the oven at operating, but the food can’t be heated Pull out the power plug, take off the outer case, discharge the capacitor, measure the resistance value of the primary winding and the secondary winding of the transformer with a multi meter (FIG.5-3 and FIG.5-4). The resistance value of the primary winding should be about 2.2 ohm, the secondary winding should be about 130 ohm, otherwise, it indicates the transformer has broken, and should be replaced by a new one.
FIG5.10 FIG.5-9 Ⅲ.REPAIRING METHOD OF SEVERAL BREAKDOWN 1. Repair when there occurred large amounts microwave leakage. There are many factors, which may cause microwave leaking. Following mentioned may be the main cause of microwave leakage: (1) The door deformed, the hinge loosed or damaged that caused the door can not close tightly. (2) The door pressing cover or the embed piece damaged or come off. (3) Obvious damage or uneven of the oven. (4) There are filth between the door and the oven.
2. Means of repair when the oven can heat, but the turntable glass can’t move Firstly, check whether the turntable holder is placed correctly. If it is correct, then pull out the power plug and take down the turntable combination, measure the resistance value of the turntable motor with Rx1k grade of a multi meter If it is opencircuited, it indicates the turntable motor has broken, and should be replaced by a new, same model one.
MOTOR TEST PROCEDURE COMPONENTS Fan Motor TEST PROCEDURE Measure the resistance. (Ohm-meter scale:R×100) (Wire leads removed) Turntable Motor RESULTS Normal:Approx. 47Ω Abnormal:∞ or Several Ω Measure the resistance. (Ohm-meter scale:R×1000) (Wire leads removed) Normal:Approx. 3.2kΩ Abnormal:∞ or Several Ω NOTE: A MICROWAVE LEAKGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON. z MAKE SURE THE WIRE LEADS ARE IN THE CORRECT POSITION.
COMMON BREAKDOWN AND MEANS OF REPAIRING PHENOMENON 1.When starting the oven, the lamp is not on, the turntable tray can’t rotate and the food can’t be heated 2.When starting the oven, the lamp is on, the turntable rotating, the fan cycling but the food can’t be heated. 3.The food can be heated, but the lamp is not on. 4.The food can be heated but the turntable tray is not rotating. 5.The oven can heat within 2-3 minutes, but can not heat from the fourth minutes. 6.
IMPORTANT THINGS TO DO PRIOR TO CRITICAL PART SERVICING The following instructions are CRITICAL to the owner’s safety. Be sure to follow all the instructions. Contact the manufacturer of distributor if you have any question. 1.1 If the oven is operative prior to servicing a Microwave Leakage Test (Microwave Emission Check) should be performed prior to servicing the oven. 1.2 2 in the event that any microwave oven found to have microwave emission level in excess of 1 mW/cm .
SAFETY CHECKS AND TESTS AFTER SERVING Constructional Checks If mechanical or electrical(electronic) parts have been replaced be sure to follow the following steps. 1.1 Check for correct wiring, adequate mechanical decrements of parts, and firm connectors. 1.2 Check for adequate grounding. 1.3 Check the following items before turning the oven ON. 1) Proper door closing, seal/choke surfaces, and hinges. 2) No outer case damage. 3) Proper interlock and monitor operations.
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A B C D E F G H J K L M S07 D00 1 1 2 L05 C00 2 3 T04 A01 3 A00 T03 A00 Z07 B03 4 S07 4 T02 T01 5 S07 S07 5 S07 E13 G06 E16 S21 S07 S05 B02 G02 Z05 W04 6 G07 S21 S03 6 7 A13 Z24 Z40 E40 E01 S02 L07 L03 L04 L03 L01 G09 E02 S05 S07 7 8 E46 E05 S07 8 S07 A16 9 S07 S17 E11 E10 W02 S07 S07 B01 Z22 9 S21 E28 10 Z01 E06 E07 10 W01 W03 S05 11 S07 S07 S06 11 12 13 14 1 46 Case Out Z24 Z22 1 11 Sponge HOLDER
REPLACEMENT PARTS LIST NOTE: When ordering replacement part(s), please use part number(s) shown in this part list. Do not use description of the part. For Model: R-662(W)M Ref No. Midea Part No. Part Name&Description Pcs/Set Remarks A00 261500116005 ASS'Y CAVITY 1 M20L SPCC A01 252100100616 COVER WAVE GUIDE 1 C17L T=0.35 A13 251502901591 BRKT THERMOSTAT 1 C17L SGCC T=0.5 A16 251502901931 BRACKET TERMAL CUTOUT(MAG) 1 C17L T=0.5 (MGT) B01 261501408000 BASE PLATE 1 M20L T=0.
REPLACEMENT PARTS LIST For Model: R-662(W)M E11 261201200020 FUSE E13+W04 263602100784 LAMP+GUIDE WIND 1 RT1-20 H 8A 250V 1 E16 261201003351 POWER CORD ASS'Y 1 E33 261201300820 THERMOSTAT 160/95 *H 1 E43 251201301370 THERMOSTAT 70/59 *V 1 G02 251200400017 HEATER QUARTZ 2 120V 500W G06 251501001566 BRKT LIGHT HEATER 1 C17L SGCC T=0.5 G07 251501100004 CONNECTOR QUARTZ HEATER 1 C17L SUS430 T=0.5 G09 261502700300 INSULATOR HEAT *T 1 A21L SGCC T=0.
REPLACEMENT PARTS LIST NOTE: When ordering replacement part(s), please use part number(s) shown in this part list. Do not use description of the part. For Model: R-662(SL)M Ref No. Midea Part No. Part Name&Description Pcs/Set Remarks A00 261500116005 ASS'Y CAVITY 1 M20L SPCC A01 252100100616 COVER WAVE GUIDE 1 C17L T=0.35 A13 251502901591 BRKT THERMOSTAT 1 C17L SGCC T=0.5 A16 251502901931 BRACKET TERMAL CUTOUT(MAG) 1 C17L T=0.5 (MGT) B01 261501408000 BASE PLATE 1 M20L T=0.
REPLACEMENT PARTS LIST For Model: R-662(SL)M E11 261201200020 FUSE E13+W04 263602100784 LAMP+GUIDE WIND 1 RT1-20 H 8A 250V 1 E16 261201003351 POWER CORD ASS'Y 1 E33 261201300820 THERMOSTAT 160/95 *H 1 E43 251201301370 THERMOSTAT 70/59 *V 1 G02 251200400017 HEATER QUARTZ 2 120V 500W G06 251501001566 BRKT LIGHT HEATER 1 C17L SGCC T=0.5 G07 251501100004 CONNECTOR QUARTZ HEATER 1 C17L SUS430 T=0.5 G09 261502700300 INSULATOR HEAT *T 1 A21L SGCC T=0.
REPLACEMENT PARTS LIST NOTE: When ordering replacement part(s), please use part number(s) shown in this part list. Do not use description of the part. For Model: R-662(K)M Ref No. Midea Part No. Part Name&Description Pcs/Set Remarks A00 261500116005 ASS'Y CAVITY 1 M20L SPCC A01 252100100616 COVER WAVE GUIDE 1 C17L T=0.35 A13 251502901591 BRKT THERMOSTAT 1 C17L SGCC T=0.5 A16 251502901931 BRACKET TERMAL CUTOUT(MAG) 1 C17L T=0.5 (MGT) B01 261501408000 BASE PLATE 1 M20L T=0.
REPLACEMENT PARTS LIST For Model: R-662(K)M E11 261201200020 FUSE 1 RT1-20 H 8A 250V E13 263600500006 LAMP 1 240V 25W E16 261201003351 POWER CORD ASS'Y 1 BS 1.0M Black E33 261201300820 THERMOSTAT 160/95 *H 1 E43 251201301370 THERMOSTAT 70/59 *V 1 G02 251200400017 HEATER QUARTZ 2 120V 500W G06 251501001566 BRKT LIGHT HEATER 1 C17L SGCC T=0.5 G07 251501100004 CONNECTOR QUARTZ HEATER 1 C17L SUS430 T=0.5 G09 261502700300 INSULATOR HEAT *T 1 A21L SGCC T=0.
