As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
VNAV 1300 FT HIGH AT TOP OF DESCENT. VNAV SLOWED A/C FIRST THEN WENT TO VNAV SPEED. VNAV WORKED FINE AT LOWER ALT. GROUNDED YES. REMOVED AND REPLACED NR 1 FMC REF MM 34 61 02 OPS CHECKED PER MM 34 61 00. PART VERIFIED WITH SEAMC MIKE. VERIFICATION FLIGHT SUCCESSFUL.