As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GND SERV DC HOT BAT C/B IS POPPED. GROUNDED - YES. FOUND GRND SER DC HOT BATT C/B ON P6-4 OUT. NO PREVIOUS HISTORY. ACCOMPLISHED C/B RESET PROCEDURE REF B737-900 AMM 20-60-01. NO DEFECTS NOTED. CLOSED C/B AND OPS GOOD REF AMM 24-34-00-00-710.