What was found
IMMEDIATELY AFTER ROTATION ON TAKEOFF, BOTH THE PILOT SIDE PFD & MFD WENT BLACK. TWO SECONDS LATER, SMOKE BEGAN TO RISE FROM IN FRONT OF THE GLARE SHIELD. THE COPILOT PFD HAD ALL RED FLAGS. NO CBS WERE POPPED & BOTH GENERATORS REMAINED ONLINE. PERFORMED AN EMER RETURN & LANDED OVERWEIGHT AT APPROX 35,000 POUNDS.IN THE COCKPIT, AN AROMA OF SOME TYPE OF ELEC BURN. PULLED BOTH CAPTAIN'S PFD & MFD. A VERY STRONG ELEC BURN SMELL COULD BE SMELLED FROM THE CAPTAIN'S PFD. INSTALLED OVERHAULED DU PFD & MFD 1 POSITION IAW MM 34-01-13-900-801. OPS CHECK ON ALL 4 DU UNITS IAW MM 34-01-13-900-801, GOOD. NO ELEC ODOR WAS SMELLED WITH AVIONICS POWER ON & DU'S RUNNING.