What was found
AIRCRAFT WAS GROUNDED: AT 400 FT UPON TAKEOFF, CA'S ELECTRIC TRIM SWITCH WAS NOT TRIMMING STABILIZER. TRIED FO'S STABILIZER TRIGGER AND ENGAGED AUTOPILOT TO SEE IF ELECTRIC TRIM INPUTS WOULD FUNCTION. STABILIZER WOULD NOT TRIM. RAN STABILIZER TRIM INOPERATIVE CHECKLIST, AIRCRAFT COULD ONLY BE TRIMMED THROUGH MANUAL WHEEL INPUTS. RETURNED BACK TO THE FIELD, EMERGENCY DECLARED AND LANDED AT 138,000 LBS, FLAPS 15 WITHOUT INCIDENT. MAINTENANCE ACCOMPLISHED STABILIZER ELECTRICAL TRIM SYSTEM CHECK IAW WITH FIM TASK 27-41-00-810-804, SYSTEM OPS CHECK GOOD, STABILIZER LEADING EDGE MOVES UP AND DOWN.