My picture is black except for a thin horizontal line

A defective display panel.

This is what is called the vertical IC, This is a flat ic on a heatsink and it could be label LA-______ something, I don't remember if it's 1601 location or what. also change out caps, like 100uf and 220uf, around this ic also loose connection are a problem with this too.

The problem is in the vertical section of the main board. Bad capacitors and maybe the vertical IC. If you are not inclined to be a tech you will have to take it to a shop.. I don't know what they may charge but I normally get $69- $89

bad vertical chip ic

Good Day, LDS also;
You may have a poor seated cable connector. Unplug TV from A/C, remove back look for a large black connector. It connects between the Main Digital Module and the Drive PWB. Re-insert both ends several times to make better contact, use contact cleaner if have but not always needed. Good Luck, big IRISH.

intermintence in vertical IC deflection its a job for experienced tech need to look for that circuit and do fine job resolding that IC

replace the focus block or try to adjust the screen control on the focus block for red only. this will affect the white balance of the set so adjust it carefully. the focus block is located on the front inside the set. remove the speaker cover then the 4 screws on the front plate. the focus block is 3" x 2" black box with 6 adjustment posts three for focus and three for screen. adjust only the affected screen (R).

sounds like the vertical, more info ctechnicians.com

The set is under a year old and is under warranty. The LVDS cable inside these sets have a history of coming loose. The problem could be the panel. Either way, the set is the problem and needs to be looked at. This set is worked on in the home and does not need to be taken to a shop, so, you can still use it. Contact Samsung at: 1-800-SAMSUNG Hope this helps.

this symptom, sometimes called the tube light effect, it is characterised by a bright thin horizontal line across the middle of the screen. this symptom is caused by a breakdown in the vertical deflection circuit. hence maybe the trouble maybe in the vertical oscillator, amplifier or output circuits. but if all i have said is not clear to you, better bring it to a qualified tv technician. good luck!