What was found
ON INITIAL TAKEOFF ROLL, UPON ADVANCING THE POWER LEVERS TO MAX TAKEOFF THRUST NR 1 ENGINE REVERSER PRESSURE LIGHT ILLUMINATED; CANCELLED THE TAKEOFF. LIGHT WENT OUT WHEN POWER WAS REDUCED TO IDLE. REVERSER NR 1 PREVIOUS DEACTIVATED AND SECURED LOCK, TRANSFERRED TO DMI NR 21213; RE-CHECKED FOUND LOCKED; DEACTIVATED "LIGHT" IN ACCORDANCE WITH M/M 78-00-22 AND DDG 78-1. ON T/S, FOUND NR 1 ENGINE THRUST REVERSER OVER PRESSURE INLET S/O VALVE AND PRESSURE REGULATOR VALVE WORKING ERRATIC. REMOVED AND REPLACED BOTH VALVES OVER PRESSURE AND REGULATOR. OPERATIONAL CHECK FOUND NORMAL IN ACCORDANCE WITH DC-10 M/M 78-31-09/78-31-05. DMI NR 21213 CLEARED (SEE LOG PAGE NR 120797).