Appliance Diagnostic

Bosch Microwave E305 Error Code - Inverter Drive Fault

E305 signals an issue with the high-voltage inverter circuit or magnetron power supply line.

What Caused This Error?

The control system reports E305 when the monitored condition described by the error code is outside the expected operating range. In this case, the most likely trigger is defective inverter control module. Other common contributors include failed magnetron tube and blown thermal cutout switch.

Step-by-Step Diagnostic Check

  1. Disconnect power plug at wall outlet.
  2. Disconnect electrical power before opening panels. Check thermal fuse continuity with multimeter.
  3. Disconnect electrical power before opening panels. Inspect high voltage wiring leads between inverter board and magnetron.
  4. Disconnect electrical power before opening panels. Replace high voltage inverter control module.
Most Likely Replacement Part

High Voltage Inverter Board

OEM Part #: MODEL-SPECIFIC

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