What was found
DEN -- FLT 661 - FLAP FAULT AND FLAPS INOPERABLE INDICATION, FLAPS FROZEN AT 18 DEGREES AFTER TAKEOFF. REMOVED AND REPLACED FLAP COMPUTER, OPS CHEKCED GOOD, INSPECTED FLAP DRIVE UNITS, CLEANED ALL FLAP CONTROL AND INDICATORS, CANNON PLUGS. OPS CHECKED GOOD MANY TIMES.