Video Input Problem

[apdicenzo]

i have a harmen karden audio/video system.
the problem is with my dvd input ,when i connect my dvd player to it i get
no picture and my dvd player says cant read.
when i bypass the harmen karden a/v input, that is, i go directly from dvd
player to the tv video input it works fine.
so i'd say its the harmen karden dvd input.
is this something i can fix my self,
what part will i need

thanks for the help