What was found
RENO, NEVADA - UPON TAXI OUT FROM GATE B-10, AIRCRAFT N1068T HAD A RADIO ALTIMETER FAIL FLAG IN BOTH RADIO ALTIMETERS. THE AIRCRAFT RETURNED TO GATE. MAINTENANCE REPLACED THE CAPTAIN'S RADIO ALTIMETER INDICATOR AND THE SYSTEM CONTINUED TO FAIL. MAINTENANCE DEFERRED THE SYSTEM IAW MEL: 34-23. MAINTENANCE INSTALLED ANOTHER RADIO ALTIMETER INDICATOR IN THE CAPTAIN'S POSITION. OPERATIONAL CHECKED NORMAL. NO DEFECTS NOTED. CLEARED THE DEFERRAL. AIRCRAFT WAS RETURNED TO SERVICE. (X)