As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AIRCRAFT NOT GROUNDED) APPROX @ TOP OF DESCENT BRIEF ACRID SMELL CB X18 POPPED, RECIRC FAN SUPPLY. PERFORMED TSM 21-21-00-810-802-A CONFIRMED RECIRC FAN FAULT. REMOVED AND REPLACED IAW AMM 21-21-51-000-001-A AND AMM 21-21-51-400-001-A OPS CHECK GOOD.