i have facing problem with bucky

when power up unit All LEDs on control panel are glow up and at the generator side all boards "Red lEDS" are glow up. except the led on the 102 Universal I/O Interface it still ON and all leds are turn off except the led on 102 Universal I/O Interface. When i expose with free cassette every thing is ok but when i try to use the bucky it be ready but there is no exposer I need Service manual too Thanks

Equipment: Philips - Optimus 50