What was found
DURING LANDING, ANTI-SKID INOP ANNUNCIATOR ILLUMINATE THEN EXTINGUISH. ROLLOUT WAS UNEVENTFUL AND DUE LONG RUNWAY, NO BRAKE APPLICATION AT ALL BUT AT END OF RUNWAY RT TURN TO TAXIWAY, BRAKES WERE NON-RESPONSIVE BUT PEDALS WERE EXTREMELY HARD. MX FOUND PRESS STILL LOCKED IN SYS FROM A/S SERVO "UPSTREAM" SEVERAL HOURS POST INCIDENT. NO BRAKE PRESS AVAILABLE AT BRAKE UNITS. PWR BRAKE MOTOR NOT CYCLING AS USUAL DUE PRESS LOCK. EVEN WITH ANTI-SKID SWITCHED OFF, BRAKES WOULD NOT RETURN TO MANUAL, MASTER CYLINDER HYD BRAKE SYS AS PER SYS DESIGN. PRESS DID BLEED OFF HOURS LATER AND SYS RETURNED TO NORM OPS W/O EXT ACTIONS. UNKNOWN WHY TEMP ANTI-SKID LITE DURING LANDING WHICH SEEMS TO HAVE CAUSED ENTIRE BRAKE SYSTEM