Black screen when power is on?

I experience the black screen of death when turning my 3DS console on.  It will power on and off, but the screen remains black.  I sent it in for repair and was told that the game slot connector pins are broken, bent, or misaligned.  How does this effect the screen?  It doesnt make sense to me.  Are the repair technicians just stopping at the first problem they see without finding the real cause for the black screen?  Please excuse my ignorance but I don't understand how the game card slot would effect the screen and not show anything at all when turning on or off.

Thanks.