As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE EVENT OCCURRED DURING C-CHECK PROCEDURE AT THE EXTERNAL POWER APPLICATION. THE NR 1 TRU START TO PRODUCE HEAVY SMOKE AND SOME COPPER PARTICLES IN FUSION. COPPER PARTICLES PRODUCE SOME BURNING HOLES IN THE EXHAUST COOLING DUCT. THE NORMAL CAUTION LIGHT NEVER COME ON BEFORE THE ELECTRICAL POWER MANUALLY CUT OFF. (TC NR 20060711003)