Sharp R-21JVF Service Manual - Page 28

R-21HT-F R-21JV-F COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE WARNING AGAINST HIGH VOLTAGE: Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result in severe, possibly fatal, electric shock. (Example) High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage Harness etc.. WARNING: Avoid possible exposure operating the oven. to microwave energy. Please follow the instructions below before 1. Disconnect the power supply cord. 2. Visually check the door and cavity face plate for damage (dents, cracks, signs of arcing etc.). Carry out any remedial work that is necessary before operating the oven. Do not operate the oven if any of the following conditions exist; 1. Door does not close firmly. 2. Door hinge, support or latch hook is damaged. 3. The door gasket or seal is damaged. 4. The door is bent or warped. 5. There are defective parts in the door interlock system. 6. There are defective parts in the microwave generating and transmission assembly. 7. There is visible damage to the oven. Do not operate the oven: 1. Without the RF gasket (Magnetron). 2. If the wave guide or oven cavity are not intact. 3. If the door is not closed. 4. If the outer case (cabinet) is not fitted. WARNING FOR WIRING To prevent an electric shock, take the following precautions. 1. Before wiring, 1) Disconnect the power supply cord. 2) Open the door and block it open. 3) Discharge the high voltage capacitor and wait for 60 seconds. 2. Don't let the wire leads touch to the followiong parts; 1) High voltage parts: Magnetron, High voltage transformer, High voltage capacitor and High voltage rectifier assembly. 2) Hot parts: Oven lamp, Magnetron, High voltage transformer, and Oven cavity. 3) Sharp edge: Bottom plate, Oven cavity, Waveguide flange, Chassis support and other metallic plate. 4) Movable parts (to prevent a fault) Fan blade, Fan motor, Switch, Switch lever and antenna motor. 3. Do not catch the wire leads in the outer case cabinet. 4. Insert the positive lock connector until its pin is locked and make sure that the wire leads do not come off even if the wire leads are pulled. 5. To prevent an error function, connect the wire leads correctly, referring to the Pictorial Diagram. Please refer to 'OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS', when carrying out any of the following removal procedures: OUTER CASE REMOVAL To remove the outer case, proceed as follows. 1. Disconnect the power supply cord. 2. Open the oven door and block it open. 3. Remove the five (5) screws from rear and along the side edge of case. 4. Slide the entire case back about 3cm to free it from retaining clips on the cavity face plate. 5. Lift the entire case from the oven. 6. Discharge the H.V. capacitor before carrying out any further work. 7. Do not operate the oven with the outer case removed. CAUTION: 1. DISCONNECT OVEN FROM POWER SUP PLY BEFORE REMOVING OUTER CASE. 2. DISCHARGE THE HIGH VOLTAGE CAPACI- TOR BEFORE TOUCHING ANY OVEN COMPONENTS OR WIRING. POWER TRANSFORMER REMOVAL 1. Disconnect the power supply cord and then remove outer case. 2. Open the oven door and block it open. 3. Discharge high voltage capacitor. 4. Disconnect the filament leads of power transformer from high voltage capacitor and the magnetron. 5. Disconnect the H.V. wire from the power transformer. 6. Disconnect the main wire harness from the power transformer. 7. Remove the two (2) screws and two (2) VCP caps holding the transformer to base plate. 8. Remove the transformer. 9. Now the power transformer is free. 26