As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHEN THE RAMP CONNECTED THE GPU, SPARKS APPEARED ON THE ACFT & NOTICED BRANDING FROM THE SPARKS ALONG WITH BURNING SMELL. GPU WAS DISCONNECTED IMMEDIATELY. MTC WAS ADVISED. EXTERNAL AC GND POWER RECEPTACLE REPLACED IAW AMM 24-42-03, FUNCTIONED IAW AMM 24-42-00-710-801-A.