ATX LTT HAS ELECTRICAL SYS FAILURE DURING DEP CLB CRUISE. FLC RETURNED TO ORIGINATION ARPT.

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I ARRIVED FOR DUTY AT PORTLAND INTL ARPT. EVERYTHING WAS PROGRESSING IN A NORMAL MANNER. DURING MY PREFLT I NOTICED THAT SELECTION OF THE SHIPS MASTER SWITCH HAD NO EFFECT ON THE MASTER RELAY AND NO VOLTAGE WAS DISPLAYED ON THE VOLTMETER. I DETERMINED THAT THE SHIPS BATTERIES WERE DISCHARGED AND ARRANGED FOR A GPU TO BE AVAILABLE AT THE PROPOSED ENG START TIME. THE ACFT STARTED NORMALLY WITH THE GPU AND DURING TAXI/WARM-UP AND THE RUN-UP CHKS ALL GAUGES AND INSTS FUNCTIONED NORMALLY. WE TOOK OFF FROM PDX; OFF RWY 02. AFTER DEP TWR INFORMED US THAT OUR XPONDER WAS NOT BEING RECEIVED. HOWEVER; THEY DID HAVE US ON PRIMARY. THIS WAS A NORMAL OCCURRENCE IN THE DEP ZONE OF RWY 02. ONCE HANDED OVER TO DEP WE WERE STILL NOT RADAR CONTACTED. AT THIS TIME WE NOTICED THAT OUR XPONDER INTERROGATION SIGNAL WAS NOT ILLUMINATING. APPROX 10 MIN LATER; WE WERE OUTBOUND ON V112; ABOUT 24 MI E OF THE BATTLEGROUND VOR WHEN I SAW THE WARNING FLAG ON MY VOR APPEAR. I THEN LOOKED OVER TO MY FO'S VOR AND HIS FLAG APPEARED SECONDS LATER. AT THIS TIME I ASKED MY FO TO REQUEST A RADAR VECTOR TO RETURN TO PDX FOR LNDG. WE WERE GIVEN A TURN TO 240 DEGS AND DSCNT CLRNC TO 6000 FT. MINS LATER I ASKED MY FO TO CONTACT DEP CTL. EXPLAIN OUR SIT AND RECEIVE INSTRUCTIONS IN THE EVENT OF LOST COMS. WE WERE INSTRUCTED TO CARRY OUT THE VOR-A APCH; CIRCLING FOR RWY 10R IN EVENT OF LOST COMS. I REALIZED THAT WE WOULD BE UNABLE TO CARRY OUT THE APCH DUE TO THE LOSS OF OUR NAV EQUIP. HOWEVER; BEFORE WE WERE ABLE TO RELAY THAT INFO TO ATC; OUR COM EQUIP FAILED; FOLLOWED SHORTLY BY OUR ADF. WE WERE UNABLE TO XMIT; HOWEVER; WE RECEIVED BLIND INSTRUCTIONS FROM ATC. WE WERE THEN CLRED FROM 6000 FT TO 4200 FT WHICH WE KNEW WOULD RETURN US TO VMC CONDITIONS. ONCE VMC AND WITHIN APPROX 10 MI FROM PDX; ATC RECEIVED A CARRIER SIGNAL WHEN I KEYED MY MIKE SWITCH AND WE WERE ABLE TO RECEIVE AND ACKNOWLEDGE LNDG INSTRUCTIONS. WE LANDED WITH NO FURTHER INCIDENT. IN CLOSING I WOULD LIKE TO ITERATE THAT WE IN NO WAY DEVIATED FROM COMPANY POLICY TO THE BEST OF MY KNOWLEDGE. THE ACFT WAS PROPERLY CONFIGURED AT ALL TIMES; AND WE USED THE ACFT CHKLIST THROUGHOUT ALL PHASES OF FLT.