What was found
A/C POSITIONED AT THE HOLD SHORT LINE WITH PARKING BRAKE SET. RELEASED BRAKE AND ATTEMPTED TO TAXI FOR TAKEOFF A/C WOULD NOT MOVE. PARKING BRAKE RESET GOT PERMISSION FROM TOWER TO POWER UP. RELEASED PARKING AGAIN. POWERED UP TO 45 PERCENT N1 WITH NO MOVEMENT OF A/C. TOWED AIRCRAFT BACK TO GATE WITH NO PROBLEMS. I.E. PARKING BRAKE RELEASED NORMALLY. PARKING BRAKE ADJUSTMENT TEST IN PROGRESS. TOWED AIRCRAFT BACK TO GATE WITH NO PROBLEMS. I.E. TOWED A/C BACK TO GATE. PARK BRAKE FUNCTIONED NORMALLY, AFTER RE-CYCLING BRAKE HANDLE SEVERAL TIMES ON GATE CARRIED OUT PARKING BRAKE/ULTIMATE EMERGENCY BRAKING OPERATIONAL TEST PER AM 32-45-00- 5. NO FAULTS FOUND, CHECKS SERVICEABLE.