Insignia No Power – Line Fuse or Power Supply Failure

Microwave will not start at all; display is blank and no lights or sounds occur when door is opened.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Blown line fuse,Defective power cord,Open thermal fuse on cavity,Failed noise filter board

How to Fix / Troubleshooting

Safety Warning: Unplug the microwave before any inspection. Internal fuses are not user-serviceable in many jurisdictions; check local regulations.

User-level checks:

  • Confirm the outlet has power by plugging in another appliance.
  • Check the circuit breaker or household fuse panel for a tripped breaker.
  • Ensure the power cord is fully inserted into the outlet and not damaged or pinched.

Technician-level steps:

  • Remove the cabinet and locate the line fuse on the filter board or near the power cord entry.
  • Test the fuse for continuity; replace only with the exact same type and rating if blown.
  • If the new fuse blows immediately, inspect door switches, high-voltage components, and wiring for shorts.
  • Check the thermal fuse/thermal cutout on the cavity or magnetron for continuity.

If you are not trained, do not replace internal fuses yourself; contact a professional.

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Repair Difficulty

Hard 4/5

Required Part

Line Fuse
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