FLC OF AN LGT ACR ACFT INADVERTENTLY WERE ON THE WRONG TWR FREQ CAUSING A DELAY IN TALKING TO THE TWR AND OVERSHOOTING THE FINAL LOC COURSE. EXECUTED A MISSED APCH.

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WE WERE TRACKING OUTBOUND ON THE STL 115 DEG RADIAL AND WERE GIVEN A TURN TO 210 DEGS AND DSND TO 2100 FT MSL. I BEGAN TUNING THE CAPT'S ILS AND CHKING FOR AN IDENT. WE WERE THEN GIVEN A TURN TO 270 DEGS TO INTERCEPT THE RWY 30R LOC MAINTAIN 2100 FT UNTIL ESTABLISHED; CLRED FOR THE RWY 30R ILS; CONTACT THE TWR ON 120.05. IN THE PROCESS OF CHANGING TO TWR FREQ THE CAPT SAID HIS ILS WAS MALFUNCTIONING. I TUNED MY ILS AND GOT AN IDENT. HOWEVER; THE COM WAS ON 120.00. THE CAPT TRANSFERRED THE AIRPLANE TO ME AND BEGAN TRYING TO CONTACT THE TWR. THE COM FREQ WAS DISCOVERED AND WHEN 120.05 WAS SELECTED THE TWR WAS TELLING US TO CLB TO 2500 FT. WE EXECUTED A MISSED APCH BECAUSE WE HAD PASSED THROUGH THE LOC. WE NEVER WENT BELOW 2100 FT BUT THE COMBINED CHAIN OF EVENTS AND A CIRCUIT BREAKER WHICH HAD POPPED ON THE FREQ CHANGE FROM VOR TO LOC FREQ LED TO A POTENTIALLY HAZARDOUS CONDITION. TIME AND DISTANCE ARE COVERED SO QUICKLY DURING THE ILS APCH IN ACTUAL IMC CONDITIONS THAT ONE MALFUNCTION CAN QUICKLY SNOWBALL ON YOU. AFTER LNDG; THE TWR ASKED WHAT HAD BEEN THE PROB AND WHEN WE SAID A CIRCUIT BREAKER HAD POPPED WHILE INITIALIZING THE APCH; THEY ONLY ASKED IF IT WAS THE SAME ACFT THAT HAD PROBS A FEW WKS EARLIER. THERE WAS NO MENTION OF ANY CONFLICT WITH OTHER TFC.