coxcctv

Please can someone help me? I recently replaced some cams on an existing domestic install, all wired with Cat 5 and baluns. On two of the cameras I am experiencing 'ghosting' when I release either camera from the dvr the 'ghosting' goes. All colours match on the cables, but the power supplies are remote from the dvr, this is only a domestic install so the runs aren't long. Any ideas ??