problem with screen when open side door

The problem with 2 computer G4 M5183, when i Open the side door for any reason, The computer dosent send any to screen, even the viga card is OK, repeat open and fix rams & wires it start work again, It happend many times before But now With the two computer Dosen't work, ??? PlZ help me, telling me what i can do because i like this model of Apple As I work in Design easy with it, Thank you for helping me in advance, hope recieve an answer from u soon.

hussein_12750@yahoo.com

Thanks Again .