What was found
THE LOSS OF THE LEFT ALTERNATOR FIELD CAUSED LEFT ALTERNATOR TO GO OFF-LINE AND TRIPPED THE REGULATOR WHICH CAUSED THE RIGHT ALTERNATOR TO GO OFF-LINE. SUBSEQUENTLY, BATTERY WAS DEPLETED AND LOSS OF ELECTRICAL POWER OCCURRED. WHEN PILOT SWITCHED REGULATORS, THE LEFT ALTERNATOR WAS NOT ALLOWING EITHER REGULATOR TO FUNCTION PROPERLY. PILOT WAS ABLE TO ISOLATE THE LEFT ALTERNATOR AND RESET THE REGULATOR AND POWER WAS RESTORED.