As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FAINT SMELL OF ELECTRICAL FUMES. TRANSIENT THEN DISSIPATED. RAN PACKS WITH APU AIR AND NOTICED SLIGHT INDUSTRIAL KIND OF SMELL. CONTINUING T/S. REMOVED BOTH COALESCER BAGS AND FOUND VERY DIRTY. REPLACED PER MM 21-51-16-3. OPERATED BOTH ENGINES PER JRH (AMT 204852). NO SMELLS NOTICED.