As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLT 3821 - Crew reported a burning smell and #1 inverter fault. Maintenance reset the #1 inverter, but could not duplicate smoke smell in cockpit. Item re-occurred on next flt 3646 with same discrepancy. Maintenance removed and replaced the #1 inverter. An operational check was performed and the aircraft was returned to service.