As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TAKEOFF WARNING HORN SOUNDED ON TAKEOFF ROLL. DURING ENGINE RUN AND TAKEOFF WARNING CHECK, FOUND NR1 CONDITION LEVER SWITCH 3151-S3 (TO WARNING HORN) OUT OF RIG. HORN SOUNDED WHEN NR1 LEVER BROUGHT BACK .0625". REPLACED AND RIGGED SWITCH 3151-S3 IAW MM 76-10-13. OPS CHECK OF TO WARNING SYS GOOD, CLEARED MEL.