TKOF ABORTED ACCOUNT WARNING HORN OF UNDETERMINED ORIGIN.

Narrative

UPON RECEIVING TKOF CLRNC FROM TWR; I APPLIED TKOF PWR. AT APPROX 30-40 KIAS; WE WERE ALERTED BY WHAT SEEMED TO BE AN AURAL HIGH TURBINE GAS TEMP (TGT) WARNING. THERE WAS NO RED MASTER WARNING ANNUNCIATION ASSOCIATED WITH THE AURAL WARNING AND ALL ENG PARAMETERS INDICATED WITHIN THEIR NORMAL RANGES. AT APPROX 40-50 KTS; I DECIDED TO ABORT THE TKOF. I INSTRUCTED THE FO TO ADVISE THE TWR THAT WE HAD REJECTED THE TKOF. WE ALSO ADVISED THE TWR THAT THE 'EQUIP' WOULD NOT BE REQUIRED AND THAT WE WOULD BE RETURNING TO THE GATE. EWR OPS WAS ADVISED; AS WELL AS OUR FLT ATTENDANTS AND PAX. THE ACFT HAD BEEN WRITTEN UP ON 2 PRIOR OCCASIONS FOR THIS PROBLEM. AS IT TURNED OUT; OUR MECHS DISCOVERED THAT THE FO'S AIRSPD INDICATOR WAS CAUSING A FALSE OVERSPD WARNING. THE OVERSPD WARNING EMITS THE SAME SOUND AS A HIGH TURBINE GAS TEMP WARNING ON THE FO MADE MLG. THE BOTH OF US ASSUMED THE AURAL WARNING WAS TURBINE GAS TEMP RELATED; DUE TO THE PREVIOUS WRITE-UPS IN THE ACFT MAINT LOG; EVEN THOUGH THERE WAS NO ASSOCIATED MASTER WARNING (RED) ANNUNCIATION. THE FACT THAT THE OVERSPD WARNING IS THE EXACT SAME AURAL SOUND CERTAINLY DIDN'T HELP MATTERS.