What was found
ON TAKE OFF ROLL, APPROX 100 KIAS F/O AIRSPEED INDICATOR NEEDLE WENT 0, CONTINUED T/O. ONCE AIRBORNE EICAS CAUTION IAS DISAGREE. RUDDER RATIO AND MACH/SPD TRIM. COMPLETED QRH PROCEDURE F/O IAS INDICATION RETURNED TO NORMAL AFTER SELECTING ALTN AIR DATA. DIVERTED, TROUBLESHOT IAW FIM 34-12-00-815-808, FIG 107 AND 34-12-00-815-813, FIG 109. FOUND FAULT BALL ON RT ADC AND WOULD NOT TEST FROM P61 PANEL.