Microwave runs (light, fan, and turntable operate) but food remains cold or only slightly warm.

Critical Safety Warning: The high-voltage section of a microwave is extremely dangerous. Do not attempt internal repairs unless you are trained and equipped to safely discharge the high-voltage capacitor.

User-level checks:

• 1. Confirm symptom: Heat a large mug of water for 2 minutes on full power. If it is still cold, heating is not occurring.
• 2. Check power level: Ensure the power level is set to 100% (High). On some Tower models, a low power setting can be mistaken for no heat.
• 3. Try different modes: If your Tower microwave has grill or combination modes, test those. If grill works but microwave does not, the magnetron circuit is specifically at fault.

Technician-level checks:

• Unplug and remove the outer cover.
• Discharge the high-voltage capacitor safely.
• Inspect the magnetron, HV transformer, HV diode, and HV capacitor for visible damage or burning.
• Test each component with appropriate methods and replace any failed parts with Tower-compatible components.

Recommendation: For most users, no-heat conditions should be handled by a professional microwave technician.