As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DEPARTURE, DURING CLIMBOUT THE CREW NOTICED THE NR 1 EPR HAD DROPPED TO 1.4 AND 600 DEG EGT AND THEY RETURNED. MAINTENACE FOUND THE OVERSPEED GOVERNOR TEST LINKAGE HAD BROKEN, PUTTING THE OSG IN TO GROUND TEST MODE, THE OSG WAS REPLACED AND ALL OPS CHECKS WERE NORMAL. NO FURTHER ACTION REQUIRED.