B727 ACFT ON APCH WAS UNABLE TO COMMUNICATE WITH APCH CTLR OR TWR DUE TO BAD #1 AND #2 RADIOS. GAR WAS EXECUTED AND CAPT DISCONNECTED HIS MIKE CORD WHICH CLRED UP THE RADIO PROB.

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TWICE DURING FLT WE EXPERIENCED LONG PERIODS OF SILENCE WHEN USING #2 VHF RADIO. WHEN CONTACT RE-ESTABLISHED ATC INFORMED US THAT IT APPEARED WE HAD A STUCK MIKE. ALL MIKE BUTTONS CHKED NORMAL. WE SUSPECTED A BAD #2 RADIO XMITTER SO WE STARTED USING #1 RADIO. OPS NORMAL UNTIL TURNING BASE LEG ON ILS TO RWY 22R AT ORD. WITH CAPT XMITTING ON #1 RADIO WE STARTED RECEIVING ONLY STATIC. SAME ON #2 RADIO. MADE TURN INBOUND ON LOC IN IMC CONDITIONS. MAINTAINED ALT UNTIL WE HEARD APCH CLR US FOR VISUAL IF FIELD IN SIGHT. UNABLE TO CONTACT TWR DUE TO STATIC. FO WAS TRYING CONTACT ON #2 RADIO AND SO WAS TRYING ON #1 RADIO WITH NO LUCK. BROKE OUT OF OVCST TOO HIGH/CLOSE FOR SAFE LNDG AND EXECUTED MISS. FINALLY CONTACTED TWR AND SWITCHED APCH. CAPT DISCONNECTED HIS MIKE CORD FROM CONSOLE AND COMS BECAME NORMAL. UNEVENTFUL APCH LDNG. MAINT SUSPECTS BAD MINI AMP IN CAPT MIKE CAUSING OPEN CIRCUIT. CALLED APCH CTL UPON ARR TO EXPLAIN WHAT HAPPENED TO SUPVR. WE WERE TOLD THAT AT NO TIME DID ANY TFC CONFLICT EXIST.