The **MAH21FCD-R** is a high-performance, high-voltage **Magnetron** manufactured by LG. It is primarily used as the microwave energy source in industrial and high-end commercial microwave ovens. --- ### 1. Key Technical Specifications The following table summarizes the primary electrical and physical characteristics of the MAH21FCD-R: | Parameter | Specification | | :--- | :--- | | **Component Type** | Microwave Magnetron | | **Frequency** | 2460 MHz (Typical S-band) | | **Output Power** | ~1000W - 1200W | | **Anode Voltage** | 4.2 kVp - 4.5 kVp | | **Filament Voltage** | 3.15 V | | **Filament Current** | 10.0 A - 12.0 A | | **Cooling Method** | Forced Air Cooled | | **Orientation** | R-Type (Right-hand airflow/mounting orientation) | --- ### 2. Electronic Sub-Assemblies The MAH21FCD-R consists of several critical electronic and physical parts that work together to generate electromagnetic waves: #### A. The Cathode and Filament * **Function:** This is the center electrode. The filament is heated by a low-voltage, high-current power source, causing "thermionic emission" (the release of electrons). * **Material:** Usually Thoriated Tungsten for durability under high heat. #### B. The Anode (Resonant Cavity) * **Function:** A hollow copper cylinder with internal "vanes" that create resonant cavities. When electrons spiral toward the anode, they induce high-frequency oscillations (microwaves) within these cavities. #### C. Permanent Magnets * **Function:** Two large ring magnets are placed above and below the vacuum chamber. They create a powerful axial magnetic field that forces the electrons to move in a circular path rather than flying straight to the anode. #### D. The Output Antenna (Probe) * **Function:** This probe extends into the waveguide. It "picks up" the RF energy from the internal cavities and launches it into the oven cavity. It is often capped with a metal "antenna cap" to prevent arcing. #### E. Filter Box (EMI Shielding) * **Function:** Located at the base where the power wires enter. It contains high-voltage capacitors and inductors (chokes) to prevent microwave energy from leaking back into the power supply circuit. --- ### 3. Common Failure Modes When troubleshooting the MAH21FCD-R, electronic technicians typically look for: 1. **Magnet Crack:** Physical cracking of the ring magnets leads to a loss of the magnetic field, causing the magnetron to draw excessive current without producing heat. 2. **Filament Continuity:** If there is no "ohm" reading between the two input terminals, the internal filament is broken (Open Circuit). 3. **Short to Ground:** There should be infinite resistance between the terminals and the metal chassis. If a reading is found, the internal ceramic insulators have likely failed. ---