As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: HEAVY PULSING DURING BRAKING ON DECELERATION DURING LANDING ROLLOUT AND INITIAL TAXI AFTER LANDING. PULSING CONTINUED THROUGH ABOUT 25-30 KNOTS AND WENT AWAY BELOW THAT SPEED. RUNWAY WAS DRY DURING LANDING. IT DID NOT FEEL LIKE ANTI SKID. MAINTENANCE FOUND #3 TACH FIN# 20GGAT FAULT AND REPLACED #3 TACH IAW AMM 32-42-57.