As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FIRST OFFICER`S ALTITUDE INDICATOR ON THE PFD SHOWED A RED X AND SPEED BUGS ON SPEED TAPE. DISAPPEARED AT VR SELECTED ADC 1 ON THE FIRST OFFICER`S REV PNL, ALL INDICATIONS NORMAL. R & R THE PFD 2 IAW AMM 34-22-01. OPS CHECKED GOOD. PERFORMED ADC SELF TEST IAW AMM 34-15-00-700-802-A. OPS CHECKED GOOD. OK FOR SERVICE.