This document is a service manual for the Svan SVMW700 microwave oven, providing comprehensive information for installation, maintenance, and troubleshooting.
Function Description
The Svan SVMW700 is a microwave oven designed for cooking and heating food. It utilizes microwave energy, generated by a magnetron, to heat food efficiently. The oven includes a turntable system to ensure even cooking and a control panel for setting cooking parameters. It also features an interlock system for safety, preventing microwave activity when the door is open.
Important Technical Specifications
- Microwave Power Output Measurement: Made at rated voltage with a 1000±5g potable water load in a cylindrical borosilicate glass vessel (max thickness 3mm, outside diameter approx. 190mm). Initial water temperature is 10±2°C. The power output (P) in watts is calculated using the formula: P = [4187 x (ΔT) + 0.55 X (T2 - To) X M] / T, where T2 is temperature after heating, To is temperature of bowl, and M is weight of bowl.
- Microwave Leakage:
- Maximum allowable emission level: 5 mW/cm².
- After servicing, leakage should not exceed 4 mW/cm².
- Leakage with the outer case removed: less than 5 mW/cm².
- Leakage for a fully assembled oven (before primary latch switch interruption) with the door slightly opened: less than 2 mW/cm².
- Ambient Temperature for Use: Less than 104°F (40°C).
- Clearance from Wall: At least 10 cm (4 inches) from the wall.
- High Voltage Capacitor: Should be discharged before servicing.
- Magnetron: Requires proper installation with a gasket to prevent microwave leakage.
- Interlock Switches: Primary, secondary, and monitor switches (Type No. KW3A) are critical for safety.
- High Voltage Transformer: Primary winding resistance approx. 1.4 ohm, secondary winding resistance approx. 90 ohm, filament winding resistance less than 1 ohm.
- Magnetron Filament Terminal Resistance: Less than 1 ohm.
- High Voltage Capacitor Resistance: Momentarily indicates several ohms, then gradually returns to 10M ohms (terminal to terminal); infinite (terminal to case).
- High Voltage Diode Continuity: Normal in forward direction, infinite in reverse direction.
- Fuse: Continuity check required. If blown, primary, secondary, and monitor switches, H.V.D., and H.V.C. should be checked.
- Heater Element (Grill) Resistance: Approx. 38 ohm (at 20-30°C). Insulation resistance: more than 0.5 Mohm.
- Thermal Cut-Out: Checks for continuity based on temperature.
- Timer Motor Resistance: Approx. 10-30K Ω.
- Fan Motor Resistance: 100-500 Ω.
- Turntable Motor Resistance: Approx. 100-200K Ω.
Usage Features
- Installation: Requires placement on a sturdy, flat surface with adequate clearance for airflow. Avoid blocking vents. Do not install near heat/steam sources or other conventional ovens.
- Earthing: Must be properly earthed for safe operation. Wires are color-coded (Green-and-yellow for Earth, Blue for Neutral, Brown for Live).
- Door Assembly: Designed to be parallel to the chassis with no play between the inner door surface and oven frame assembly to prevent microwave leakage.
- Turntable System: Includes a glass tray and a turntable motor for rotating food during cooking.
Maintenance Features
- Safety Precautions:
- Always disconnect the power plug before touching any parts.
- Discharge the high voltage capacitor by shorting its terminals with an insulated screwdriver (wait 30 seconds after oven stops).
- Never operate the oven with a 2-wire extension cord.
- Never touch oven components or wiring during operation.
- Avoid contact with high voltage parts.
- Do not operate the oven with no load.
- Do not injure the door seal or oven cavity.
- Do not place iron tools on the magnetron or anything into the latch hole/interlock switch area.
- Remove watches when working near the magnetron.
- Microwave Leakage Test: Essential before and after servicing, especially after magnetron replacement or any repair involving microwave energy blocking devices. Use a microwave survey meter with a 2-inch (5cm) spacer.
- Component Testing: Detailed procedures for testing the high voltage transformer, magnetron, high voltage capacitor, diode, fuse, heater element, thermal cut-out, timer motor, fan motor, and turntable motor using an ohmmeter.
- Disassembly and Adjustment: Step-by-step instructions for removing the outer case, power supply cord, control panel, door assembly, high voltage transformer, orifice assembly, H.V. capacitor and diode, air guide assembly, magnetron, turntable motor, and timer motor.
- Interlock System Continuity Test: Procedures for checking the primary, secondary, and monitor switches to ensure proper operation and safety. This test is crucial after repairing the door or interlock system.
- Troubleshooting Guide: Provides conditions, causes, and remedies for common issues such as the oven not working, low output power, sparks, uneven cooking, and turntable noise.
- Qualified Personnel: Emphasizes that servicing should only be performed by properly qualified service personnel.
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