What was found
CAPTAINS ALTIMETER, ALTITUDE PRESELECT, TRANSPONDER, AND TCAS FAILED ON DEPARTURE. LANDED AND RETURNED TO GATE. THIS IS THE SECOND REPORT OF THIS PROBLEM ON THIS AIRCRAFT IN 2 DAYS. MAINTENANCE PERSONNEL GROUND TESTED THE SYSTEM AND DETERMINED THAT THE ENCODING ALTIMETER WAS NOT FUNCTIONING PROPERLY. CAPTAINS ALTIMETER WAS REMOVED, REPLACED, AND GROUND TESTS COMPLETED WITH NO DISCREPANCIES NOTED. (M)