AN MD83; JUST AFTER ROTATION; DECLARED AN EMER DUE TO BOTH BUSES ALTERNATING L TO R. LOST #1 AND #2 EFIS; PRIMARY INSTRUMENTS; AND ALTIMETERS. CREW LANDED OVERWT. FLT CREW NOTED THAT THE FLT MANUAL CONTAINED NO PROCEDURE TO ADDRESS THIS SITUATION.

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JUST AFTER ROTATION BOTH BUSES STARTED TO ALTERNATE ON AND OFF LINE. LOST BOTH CAPT AND FO EFIS AND PRIMARY AIRSPEED AND ALTIMETERS AND VSI. ALL COCKPIT AND CABIN LIGHTING WAS INTERMITTENT. L AND R GENERATOR OFF LIGHTS WERE FLICKERING. STARTED APU AND DECLARED AN EMER FOR A 148300 LB OVERWT LNDG. APCH AND LNDG ON RWY 14R UNEVENTFUL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED BOTH L AND R BUSES ALTERNATED OFF AND ON IN A FAIRLY HIGH FREQUENCY WITH THE L AND R GENERATOR 'OFF' LIGHTS FLICKERING. LOST L AND R EFIS; ALL AIR DATA INSTRUMENTS; AND ALL CABIN AND COCKPIT LIGHTING FLICKERING. IT APPEARS THE GENERATORS WERE ATTEMPTING TO PARALLEL. THIS EVENT WENT ON FOR 30 SECONDS TO 1 MINUTE. THE RPTR FOLLOWED UP ON THE CAUSE OF THE MALFUNCTION AND FOUND THE MAINT FIX WAS REPLACEMENT OF BOTH CONSTANT SPD DRIVES DUE TO OUTPUT FREQUENCIES OUT OF LIMITS. THE RPTR HAD NEVER EXPERIENCED AN EVENT OF THIS NATURE AND BELIEVED IT WAS FORTUNATE TO HAPPEN IN DAY VFR. ONE FACT NOTICED WAS THAT THE STANDBY INSTRUMENTS OPERATED AS ADVERTISED. CALLBACK CONVERSATION WITH RPTR ACN 670698 REVEALED THE FOLLOWING INFO: RPTR STATED THAT RIGHT AFTER ROTATION; THE LIGHTS STARTED FLASHING ON AND OFF AND THE AC POWER RELAYS BEHIND THE CAPT'S SEAT WERE CLACKING AND BANGING. LOST EFIS; VSI; ALTIMETERS; AND AIRSPD INDICATIONS. DECLARED AN EMER; STARTED THE AUXILIARY POWER UNIT; AND LANDED OVERWT. BELIEVED THE L GENERATOR WAS REPLACED. RPTR ALSO STATED THAT THERE IS NO PROC FOR THIS TYPE OF EVENT IN THE QRH.