What was found
SEA FLIGHT NR 2380: WE GOT THE TAKE-OFF WARNING DURING THE NORMAL TEST DURING TAXI OUT. WE DOUBLE CHECKED ALL THE SYSTEMS AND STILL KEPT GETTING THE HORN. WE DID A TRIM ELEVATOR TEST AND NOTICED THAT THE INDICATOR DID NOT GO ALL THE WAY TO NU POSITION. RETURNED TO GATE. MAINTENANCE C/W THE OPERATIONAL TEST OF THE ELEVATOR PITCH TRIM SYSTEM PER Q400 AMM TASK 37-32-000-710-802. OPS CHECK GOOD. PERFORMED FUNCTIONAL TEST OF THE TAKE-OFF WARNING SYSTEM. OPS CHECK GOOD. NO FURTHER DEFECTS NOTICED. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.