Hi
If the lines are fairly static thin white lines & the pix is a bit overbright, this is a fault condition.
Either Line transformer screen assy or a CRT Drive problem
(My guess without seening the fault ) , contact Samsung service if under warranty or take it to your favourite repairer.
Good luck & hope this helps
Here you are a tech website www.tvrepairjacksonvillefl.com
ernest
December 2012