PWR FAILURE TO A MODEM THAT XMITS DATA FROM THE RADAR SITE TO THE TRACON CAUSED AN OUTAGE AT PIT. THE BACKUP PWR SOURCE WAS NOT A FACTOR BECAUSE A CIRCUIT BREAKER HAD TO BE MANUALLY RESET BY AN AIRWAYS FACILITIES TECHNICIAN AT THE RADAR SITE BEFORE ANY PWR WAS USABLE.

Narrative

AT XX07 AM EDT; THE PRIMARY RADAR DATA AT THE PIT ATCT FAILED DUE TO A LOSS OF PWR TO THE MODEM WHICH XMITS THE DATA FROM THE RADAR ANTENNA SITE TO THE FACILITY. NO BACKUP PWR SOURCE WAS AVAILABLE AND THE CIRCUIT BREAKER THAT TRIPPED HAD TO BE RESET BY A TECHNICIAN AT THE SITE. AT THE TIME OF THE OCCURRENCE; I WAS WORKING THE ARR CTL; S POS; VECTORING ACFT FOR THE VISUAL APCH TO RWY 10R. AT THE TIME OF THE FAILURE I HAD 2 ACFT ON FREQ AND 3 ACFT HAD JUST BEEN TURNED OVER TO THE TWR ON VISUAL APCHS. AS I NOTICED THE RADAR FAIL I ASKED THE LAST ACFT I WAS VECTORING IF HE COULD POSSIBLY SEE HIS TFC. AS LUCK WOULD HAVE IT HE ADVISED HIS TFC WAS IN SIGHT AND I TOLD HIM TO MAINTAIN VISUAL SEPARATION AND FOLLOW THE TFC TO THE ARPT AND EXPLAINED THE SIT TO THE 2 ACFT ON MY FREQ. I ADVISED THEM BOTH THAT TFC TO THEIR N HAD BEEN ON VECTORS AND MAY FLY THROUGH THE RWY 10L FINAL AND THEY SHOULD BOTH EXERCISE EXTREME CAUTION AND KEEP THEIR EYES OPEN. THIS INCIDENT; IN MY OPINION; WAS A THREAT TO PAX SAFETY.