Even when I do it myself. I usually have to get the service manual (try www.samsungparts.com) and then borrow an oscilloscope or other test gear from the office. Some folk have no electronics test or repair background so those folk are often upset when they get the manuals and find nothing there for the average joe.
Had my LE40a656A1FXXU for about 3,5 years and today the TV will not start.
The red light is blinking and it makes a noise, like a fan is starting and then stops, repeatedly.