A cleared fuse is a result, not the root cause. Isolate the equipment, verify that stored energy is discharged and inspect the protected semiconductor stage for shorted devices, damaged buswork, loose joints or cooling faults before fitting a replacement.

Check the striker or indicator and confirm continuity only with the circuit de-energized. Replace the fuse only after the fault source is corrected; energizing against an uncleared short can immediately operate the new fuse.

Match the complete 170M5388 / PC72UD13C250T / 3AUA0000090404 identity, aR class, voltage rating, current rating, size-2 footprint and indicator arrangement. Do not substitute a general-purpose gG or gL fuse.

Clean and inspect the mounting faces, tighten connections to the documented torque, preserve phase orientation and verify coordination with the protected converter or drive before recommissioning.