As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE FLIGHT CREW RETURNED TO THE GATE AFTER EXPERIENCING A NR 1 HYD HOT CAUTION LIGHT DURING TAXI FOR TAKEOFF. MAINTENANCE REPLACED THE NR 1 SYSTEM STANDBY POWEER UNIT AND THE AIRCRAFT RETURNED TO SERVICE. THIS UNIT HAD RECENTLY BEEN REPAIRED BY THE VENDOR. TTSN, TCSN WERE NOT READILY AVAILABLE DUE TO THIS UNIT BEING A LOANER.