As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TESTING OF LT PACK SYS, HEARD A TATTLING METALLIC NOISE COMING FROM THE LT PACK REHEATER, SUSPECT A SMALL BROKEN PIECE OF METAL INSIDE THE REHEATER. FOUND A BROKEN BONDING SPRING RING INSIDE THE REHEATER, REMOVED ALL BROKEN PARTS AND REPLACED BONDING SPRING ON REHEATER DUCT, LEAK CHECK AND OPS CHECKED ALL NORMAL.