As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TWENTY MINUTES AFTER TAKEOFF AND CRUISING AT 15,000 FT, THE APU WAS STARTED AND A STRONG ELECTRICAL BURNING ODOR WAS NOTED. THE BLEED AIR WAS TURNED OFF AND APU SHUTDOWN. DIVERTED AND LANDED WITHOUT INCIDENT. MAINTENANCE RAN ACFT AND INSPECTED ACFT, COULD NOT FIND ANY ELECTRICAL PROBLEMS. CHANGED THE COALESCER ASSEMBLY FIXED THE PROBLEM.