What was found
(CAN) WHEN A/C POWERED UP, LOWER PILOT'S EFIS DISPLAY REMAINED BLANK. LOWER CO-PILOTS EFIS DISPLAY SWITCHED FOR TROUBLE SHOOTING. DISPLAY ALSO REMAINED BLANK. WHEN DISPLAY RETURNED TO IT'S ORIG POSSITION, IT REMAINEDBLANK AS WELL. IT DETERMINED THROUGH FURTHER TROUBLE SHOOTING THAT PILOT'S SG-465 SYMBOL GEN P/N 066-04021-11-11, S/N 4481, DEFECTIVE. IT CAUSED INTERNAL DAMAGE TO LOWER PILOT'S EFIS DISPLAY, P/N 066-03125-2500, S/N 3486. WHEN CO-PILOT'S EFIS DISPLAY INST IN POSSITION, IT TOO DAMAGED BY DEFECTIVE SYMBOL GEN. WHEN EFIS DISPLAY RETURNED TO IT'S ORIG POSSITION, IT IN TURN DAMAGED CO-PILOTS SYMBOL GEN,S/N 3354. PI LOT'S SYMBOL GEN&LOWER EFIS DISPLAY, AND