What was found
UNCOMMANDED FLAP DEPLOYMENT DURING T/O ROLL. AIR TURNBACK. MAINTENANCE COMPLETED TROUBLESHOOTING PROCEDURES IAW CHAP 27 AMM. FLAP CONTROL OPS CHECK, AND FCB RIG CHECK GOOD. COULD NOT DUPLICATE WRITE-UP. SUSPECT BAD VALVE, MAINTENANCE REPLACED FLAP CONTROL VALVE P/N HP1416100-S, S/N ON 1580, SN OFF 1053. ALL RIGGING WITHIN LIMITS. ALL CHECKS GOOD IAW CHAP 27.