As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE OPERATING WITH DISPLAY FAN #1 ON MEL CREW RECEIVED DISPLAY COOL CAUTION. C/W QRH AND MESSAGE DID NOT CLEAR. PERFORMED AIR RETURN TO FSD. AIRCRAFT REMOVED FROM SERVICE REMOVED FO PFD & MFD & CLEANED AIR FILTER IAW AMM 31-61-01. PERFORMED OPS CHECK OF DISPLAYS AND DISPLAY FANS IAW AMM 31-61-01 & 21-24-00. OPS CHECKS GOOD, COULD NOT DUPLICATE FAULT.