As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED A BURNING SMELL IN THE COCKPIT THAT SEEMS TO BE COMING FROM THE RIGHT HAND PACK. MAINTENANCE INSPECTED AND FOUND THAT THE APU WAS FAILING THE COMPRESSION CHECK. THE APU WAS THEN DEFERRED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.