This is the most prevalent and critical problem. If your LG microwave appears to turn on (light, display, fan, turntable might work), but the food remains cold after the cycle, it almost invariably points to a failure within the high-voltage circuit. This includes a faulty magnetron (the component generating microwave energy), a defective high-voltage diode, a failing high-voltage capacitor, or a malfunctioning high-voltage transformer. Due to the dangerous levels of electricity involved, attempting to fix this yourself is extremely hazardous.

 If your LG microwave is completely unresponsive – no lights, no display, no fan – the problem is electrical. Common causes include a tripped household circuit breaker, a blown ceramic fuse (often located internally within the microwave), a faulty door interlock switch (a crucial safety mechanism that cuts power if the door isn’t properly latched), or a defective main control board. We safely test all electrical pathways to diagnose the power issue.

 For even and thorough cooking, the turntable needs to rotate. If your LG microwave’s turntable is stationary, it could be due to a faulty turntable motor, a worn or dirty turntable roller guide beneath the glass tray, or, less commonly, an issue with the control board. Sometimes, it’s as simple as the turntable being misaligned or overloaded.

While a microwave emits a characteristic humming sound during operation, any unusual noises like excessive buzzing, grinding, rattling, a loud pulsating hum, or a high-pitched whine can indicate a problem. This might stem from a faulty magnetron, a defective cooling fan (which prevents overheating of internal components), a worn turntable motor, or a loose component vibrating inside the unit.

The microwave will not operate if the door is not securely closed, as mandated by multiple safety interlock switches. If your LG microwave door doesn’t latch, appears loose, or causes the microwave to not start, it could be due to a faulty door latch assembly, damaged hinges, or a problem with the interlock switches themselves. This is a critical safety issue.

A non-functional interior light makes it hard to monitor food while cooking, and a dark control panel light makes selecting settings difficult. This could be a burnt-out bulb (for interior light), a faulty light switch, or a problem with the control board.

If your LG microwave abruptly stops cooking before the timer runs out, it could be caused by a faulty door interlock switch (intermittently losing connection), an overheating issue (triggering a thermal cut-off switch), or an intermittent problem with the main control board.

 If you ever notice a burning smell or see smoke emanating from your LG microwave, immediately unplug the appliance and do not use it again. This could be due to a short circuit, arcing inside the microwave cavity (often from metal objects or a damaged waveguide cover), or a faulty, overheating component like the magnetron or transformer. This requires immediate, professional inspection due to potential fire hazards.

If you see bright sparks or arcing inside the microwave cavity (often near the right-side wall where the waveguide is located), it’s typically caused by food debris, a damaged waveguide cover (a thin mica sheet that protects the waveguide), or inadvertently placing metal objects inside the microwave. Continued arcing can permanently damage the magnetron and the microwave cavity.

A malfunctioning digital display can make it impossible to select cooking settings, view the timer, or understand status. This often points to a problem with the display board itself, its power supply, or the main control board.