Good evening ... Let's see if I understand? When the TV was brought to you, the fault was a horizontal line on the screen? I do not understand these lines of your story ... Now, the 3DD5036 transistor according to its datasheet is a horizontal output transistor of 1700 Volts by 8 Amps, with damper diode, therefore the C5387 cannot be a replacement since it lacks This diode So the TV always had what it really was a vertical failure ...