Sharp R-222STM Service Manual
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Sharp R-222STM Service Manual

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CHAPTER 1. SAFTY PRECAUTIONS
CHAPTER 2. CAUTIONS
CHAPTER 3. THE HEATING PRINCIPLE OF MICRO-
WAVE
CHAPTER 4. INSTALLATIONS
CHAPTER 5. SCHEMATIC DIAGRAM
CHAPTER 6. CIRCUIT DESCRIPTION
CHAPTER 7. TOOLS AND MEASURING INSTRUMENTS
CHAPTER 8. MICROWAVE LEAAGE TEST
SERVICE MANUAL
CONTENTS
SHARP CORPORATION
MICROWAVE OVEN
MODEL
(800W 240V50Hz)
In interests of user-safety the oven should be restored to its
original condition and only parts identical to those specified
should be used.
CHAPTER 9. MEASUREMENT OF MICROWAVE
POWER OUTPUT
CHAPTER 10. TROUBLE SHOOTING PROCEDURES
CHAPTER 11.
COMMON BREAKDOWN AND MEANS OF
PREPARING
CHAPTER 12. IMPORTANT THINGS TO DO PRIOR
CRITICAL PART SERVICING
CHAPTER 13. SAFTY CHEC S AND TESTS AFTER
SERVING
CHAPTER 14.
EXPLODED VIEW
Parts List
This document has been published to be used
for after sales service only.
The contents are subject to change without notice.
R-222STM
R-222STM
K

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  • Page 1 R-222STM SERVICE MANUAL MICROWAVE OVEN R-222STM MODEL (800W 240V50Hz) 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.

  • Page 2: Safety Precautions

    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...

  • Page 3: Table Of Contents

    TABLE OF CONTENTS （page） SAFETY PRECAUTIONS------------------------------------ ------Inside front cover --------------- CAUTIONS------------------------------------------------------------------------------------------------1-1 THE HEATING PRINCIPLE OF MICROWAVE--------------------------------------------------2-1 INSTALLATIONS----------------------------------------------------------------------------------------3-1 OPERATING INSTRUCTIONS----------------------------------------------------------------------4-1 SCHEMATIC DIAGRAM--------------------------------------------------------------------------4-1 CIRCUIT DESCRIPTION-------------------------------------------------------------------------4-2 SERVICE INFORMATION-----------------------------------------------------------------------------5-1 TOOLS AND MEASURING INSTRUMENTS------------------------------------------------5-1 MICROWAVE LEAKAGE TEST----------------------------------------------------------------5-2 MEASUREMENT OF MICROWAVE POWER OUTPUT---------------------------------5-3 TROUBLE SHOOTING PROCEDURES------------------------------------------------------5-4 COMMON BREAKDOWN AND MEANS OF REPAIRING-------------------------------5-8 IMPORTANT THINGS TO DO PRIOR TO CRITICAL PART SERVICING-------------------------5-9 SAFETY CHECKS AND TESTS AFTER SERVING--------------------------------------5-10...

  • Page 4: Cautions

    CAUTIONS Unlike other appliances, the microwave oven MICROWAVE RADIATION high-voltage and high-current equipment. Personnel should not be exposed to the Though it is free from danger in ordinary use, microwave energy which may radiate from the extreme care should be taken during repair. magnetron or other microwave generating device if it is improperly used or connection.

  • Page 5: The Heating Principle Of Microwave

    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.

  • Page 6: Installations

    INSTALLATIONS BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY INSTALLING EARTHING INSTRUCTIONS 1. Empty the microwave oven and clean inside it with This microwave oven is designed to be used in a fully a soft, damp cloth. Check for damage such as earthed condition.

  • Page 7: Schematic Diagram

    SCHEMATIC DIAGRAM...

  • Page 8: Circuit Description

    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.

  • Page 9: Service Information

    SERVICE INFORMATION TOOLS AND MEASURING INSTRUMENTS NECESSARY TOOLS NECESSARY MEASURING Tools normally used for TV servicing are sufficient. INSTRUMENTS Standard tools are listed below. • TESTER(VOLTS-DC, AC., Ohmmeter) • Diagonal pliers • Microwave survey meter • Long nose pliers - Holaday HI-1710(A) •...
  • Page 10 MEASUREMENT WITH OUTER CASE NOTES WHEN MEASURING REMOVED • Do not exceed meter full scale deflection. • 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.

  • Page 11: Measurement Of Microwave Power Output

    MEASUREMENT OF MICROWAVE POWER OUTPUT • Microwave power output measurement is made with • The microwave power output P in watts is the microwave oven supplied at its rated voltage and calculated operated at its maximum microwave power setting with approximately from the following formula : a load of (1000±5) g of potable water.

  • Page 12: Trouble Shooting Procedures

    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.
  • Page 13 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.
  • Page 14 FIG.5-8 FIG.5-7 FIG5.10 FIG.5-9 Ⅲ.REPAIRING METHOD OF SEVERAL BREAKDOWN 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.
  • Page 15 If there still exist microwave leakage, measure near the magnetron with the probe of the microwave leakage measure. If the leakage is larger, the oven should be turned off and check whether the 2 or 4 screws which fix the magnetron have been loosed, if loosed, twist them tightly with socket wrench.
  • Page 16 MOTOR TEST PROCEDURE COMPONENTS TEST PROCEDURE RESULTS Measure the resistance. Fan Motor (Ohm-meter scale:R×100) Normal:Approx. 47Ω (Wire leads removed) ∞ Abnormal: or Several Ω Measure the resistance. Turntable Motor (Ohm-meter scale:R×1000) Normal:Approx. 3.2kΩ (Wire leads removed) ∞ Abnormal: or Several Ω NOTE: A MICROWAVE LEAKGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON.

  • Page 17: Common Breakdown And Means Of Repairing

    COMMON BREAKDOWN AND MEANS OF REPAIRING PHENOMENON CAUSE REPAIRING MEANS 1. fuse broken 1. Change a new fuse. 2. The primary and secondary winding of the 2. Change transformer are short-circuited. transformer. 1.When starting 3. The earthing or the polarity of the capacitor is 3.

  • Page 18: Important Things To Do Prior To Critical Part Servicing

    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. If the oven is operative prior to servicing a Microwave Leakage Test (Microwave Emission Check) should be performed prior to servicing the oven.

  • Page 19: Safety Checks And Tests After Serving

    SAFETY CHECKS AND TESTS AFTER SERVING Constructional Checks If mechanical or electrical(electronic) parts have been replaced be sure to follow the following steps. Check for correct wiring, adequate mechanical decrements of parts, and firm connectors. Check for adequate grounding. Check the following items before turning the oven ON. Proper door closing, seal/choke surfaces, and hinges.

  • Page 22: Replacement Parts List

    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. or Model: R-222STM Ref No. Midea Part No. Part Name&Description Pcs/Set Remarks 261500115007 ASS'Y CAVITY 252100100616...
  • Page 23 REPLACEMENT PARTS LIST R-222STM For Model: 251200100068 MAGNETRON 261200201560 H.V.TRANSFORMER 251200701306 H.V.CAPACITOR 251200900861 H.V.DIODE 261400300064 NOISE FILTER 261201200030 FUSE 263600500007 LAMP 261201001932 POWER CORD ASS'Y 261201300820 THERMOSTAT 160/95 *H 261301300705 BRKT INTERLOCK 261301100101 LEVER SWITCH 261201600080 MICROSWITCH INTERLOCK 261201600150 MICROSWITCH MONITOR...

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