ACR LGT HAD AN AURAL SIGNAL WARNING FAILURE THAT RESULTED IN ACTIVATING THE WARNING SIGNAL. AURAL SIGNAL WAS VERY LOUD AND CAUSED FLC DISTR.

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WE TOOK OFF FROM PORTLAND; ME; FOR 28 MIN FLT TO BOS. SHORTLY AFTER OUT OF 10K; THE 'OVERSPD WARNING' LIGHTS LIT UP AND THE LOUD HOWLING SIREN OR WHATEVER IT IS FILLED THE COCKPIT. WE WERE WELL BELOW VNE; VMA/MMO. THE COPLT BARBER POLE WAS STUCK AT ABOUT 250K AND WE WERE GOING 300. SWITCHED TO HIS ALTERNATE AIRDATA COMPUTER WHICH MOVED POLE TO ABOUT 340K; BUT WARNINGS PERSISTED. (MEANWHILE PRESSING ON TO BOS). I HAD FO TRY TO FIND AN AURAL WARNING HORN CIRCUIT BREAKER; SO HE WAS OUT OF HIS SEAT. I ASKED CENTER FOR HDGS RATHER THAN ME NAVIGATE. THE DAMN NOISE WAS SO LOUD I MISSED SEVERAL CALLS (I ALSO WAS INTERACTING SOMEWHAT WITH FO BECAUSE HE COULDN'T FIND CIRCUIT BREAKERS. FINALLY TOLD HIM TO GET INTO SEAT; I HAD THEN SLOWED BELOW 250 AND SIREN BECAME INTERMITTENT OR STOPPED. GIVEN HDG TO INTERCEPT RWY 27 LOC AT BOS WHILE FO WAS GETTING SEATED (ABOUT 15 MI OUT PLUS/MINUS). RATHER THAN HAVE AUTOPLT DO A HVY BANK TO INTERCEPT; I SELECTED LNAV FOR A MORE GRADUAL TURN ON SINCE SPD STILL OVER 230 KTS AND DECREASING. THE LNAV DID NOT CAPTURE SINCE WE WERE SO CLOSE TO LOC AND BELOW THE CLOUDS. I THINK WE WERE GIVEN SOMETHING LIKE 1700 FT TO INTERCEPT; BUT WE WERE BELOW THE CLOUDS IN GOOD VFR WITH ARPT IN SIGHT AND AT THAT TIME DOING THE DSCNT AND APCH CHKLISTS. I NOTICED WE OVERSHOT THE LOC AND WAS TURNING BACK TOWARD THE R TO GET ON IT AND SELECTED LOC ON FLT DIRECTOR. MEANWHILE; I LET THE ALT GO TO ABOUT 1400-1450 FT (250 +/- BELOW INTERCEPT AT OUTER FIX). APCH GAVE US A HDG TO 300 DEGS AND CLRED US FOR A VISUAL APCH; THEY HAD BEEN ADVISED WE WERE A BIT BUSY AND MADE NO FURTHER COMMENT. IN RETROSPECT; I SIMPLY DISCONNECTED THE AUTOPLT AND PROCEEDED VFR TO THE LOC. THE DEV WAS SLIGHTLY TO THE L OF COURSE AND SHOULD HAVE CIRCLED SOMEWHERE WHEN THE WARNINGS WENT OFF; BUT THE ONLY THING ABOUT IT THAT CONCERNED ME WAS THAT DAMN NOISY WARNING WAIL AND WE HAD NO WAY OF FINDING THE CIRCUIT BREAKERS AS IT IS NOT IN OUR BOOK TO DISABLE THE STUPID THING. AS IT TURNED OUT; THERE ARE 2 CIRCUIT BREAKERS THAT CAN SHUT THE NOISE OFF AT THE SPEAKER; BUT ONLY MAINT HAS THE INFO ON HOW TO FIND THEM FROM A GRID PATH; RATHER THE SEARCH AND MISS TECHNIQUE WE TRIED TO USE ON THE SHORT FLT.