A/C fitted with dual AF3500 (efis and em). When I switched on the master, both screens booted up as per normal. Shortly after getting to the main efis page, the screen suddenly went completely dim. No buttons worked and shut down required pulling fuse. Screen would not respond at all when power was reset. The screen now also has a darker appearance to the EM screen. Any ideas? The unit has only 6 hours of use, diodes are fitted as per instructions, and failure occured prior to engine start, on a/c battery power Has anyone seen this before?