Chosen Solution
Hi, I have a 55 inch Samsung TV model#LN55B650T1F. After being shut off for the night and turning it back on in the morning,I have black screen with sound. After un plugging it for several minutes it works fine all day.
Hi @amj62 , Is this intermittent or happens every time after it has been turned off for the night or just turned off? When you turn it on for the first time in the a.m. and there is a black screen and audio, try shining a torch at an angle close to the screen to check if there is an image there or not. It will be very faint if it is there, so trying this in a darkened room may help. If there is an image detected then there is a backlight problem. Either with the power board, the LED backlights or perhaps the mainboard not telling the power board to turn the backlights on. Try the following: Turn off the TV and then disconnect the power from the TV. Remove the back cover from the TV and then disconnect the cable between the mainboard and the power board. Reconnect the power to the TV and turn the TV on. The TV backlights should turn full on and stay on. There will be no picture because the mainboard is disconnected. If the backlights do not turn on, check the voltage at the LED connector on the power board. If there is >220V DC there is a problem with the LED backlight array. If there is <30V DC there is a problem with the power board. If there is no image detected then it may be a mainboard or power board problem. Check the power board for bulging capacitors or heat affected components If it is intermittent then this will make it more difficult to find as touching things may disturb something while you are trying to find out what the problem may be and it may not fail afterwards for a while. Hopefully never but if it doesn’t fail regularly or you can’t make it fail then the problem could be anywhere.
