ACR HAS ERRONEOUS NAV INDICATIONS. ELECTRONIC EQUIP IN USE IN CABIN.

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FLYING AN EXTRA SECTION OF NEWS MEDIA TO YYZ. ON A L BASE LEG; APCH CTL CLRED US FOR APCH AND GAVE US A HDG OF 270 DEGS TO INTERCEPT 24L LOC. I HAD THE ACFT ON AUTOPLT AND SELECTED APCH MODE. AS THE ACFT REACHED 270 DEGS IT CAPTURED THE LOC. LOC LOCK WAS ANNUNCIATED ON THE ANNUNCIATOR PANEL AND THE ACFT TURNED TO 237 DEGS (THE INBOUND HDG). HOWEVER; MY CDI NEEDLE WAS STILL FULL R. VISIBILITY WAS ABOUT 5 MI AND WE WERE ABOUT 9 MI OUT. LANDMARKS ON THE GND APPEARED NORMAL FOR LOC PATH AND THE ADFG NEEDLE WAS CORRECT FOR INBOUND HDG. I RE-EXECUTED THE FMC; WHICH HAD THE 24L APCH LOADED; AND IT INDICATED THE CORRECT BEARING TO THE RWY. THE FO STILL HAD THE FMC SELECTED FOR THE CDI AND I HAD HIM SELECT THE ILS. HIS CDI NEEDLE THEN WENT FULL R DEFLECTION. THERE WERE NO WARNING FLAGS DISPLAYED; ACFT CONTINUED ON CORRECT LOC PATH. BY NOW; WE WERE APCHING THE OM AND THE FIELD AND 24L RWY WERE VISIBLE. WE CONFIGURED FOR FINAL APCH; STARTED DOWN THE GS; AND SUDDENLY; BOTH CDI NEEDLES SNAPPED BACK TO CTR POS. WE COMPLETED THE APCH AND LNDG WITHOUT FURTHER INCIDENT. TAXIING IN; WE TOLD THE TWR THAT WE HAD INSTRUMENTATION PROBS ON FINAL. TWR RPTED THAT THERE WAS NO ACFT ON THE APCH BEHIND US. THERE WAS AN MLG AT THE HOLD SHORT LINE AWAITING TKOF ON 24L. NOW; BACK TO THE BEGINNING OF THE STORY: NEWS MEDIA; ELECTRONIC GEAR; CAMERAS! WHEN WE ARRIVED AT THE GATE; I IMMEDIATELY WENT TO THE CABIN AND ASKED ONE OF THE FLT ATTENDANTS IF ANYONE HAD BEEN USING ANY ELECTRONIC EQUIP. SHE SAID A CAMERAMAN HAD ASKED HER EARLIER IN THE FLT IF SHE KNEW IF HE WOULD BE ABLE TO SEE THE SKYDOME ON ARR. SHE SAID SHE TOLD HIM THAT SHE DIDN'T KNOW IF THE APCH WOULD FLY BY IT. LATER; ON THE FINAL CABIN WALK-THROUGH BEFORE LNDG; SHE SAW THE SAME MAN WITH A CAMERA PRESSED TO A WINDOW. AS SHE APCHED HIM; HE CEASED FILMING AND STOWED THE CAMERA (LARGE HAND-HELD TYPE). I ASKED HER IF THAT WAS ABOUT THE TIME THE GEAR WENT DOWN. SHE SAID YES! DUE TO THE CLOSE COINCIDENCE BTWN THE OP OF THE TV CAMERA AND THE IMPROPER DEFLECTION OF THE CDI NEEDLES; I SUSPECT ELECTROMAGNETIC INTERFERENCE. THE CAMERA HAD A 12 VOLT BATTERY. THE AIRLINE FLT OPS MANUAL CALLS FOR ELECTRONIC EQUIP TO BE TURNED OFF DURING TAXI; TKOF; AND LNDG. I WOULD SUGGEST THAT THEY BE OFF BELOW 10000 FT UNTIL IT CAN BE DETERMINED WHAT EFFECTS THIS GEAR HAS ON ACFT INSTRUMENTATION.