Chosen Solution
When powering on from being in the off-state for a few hours, my Samsung MU6470 123cm works fine. Picture is good, everything is normal. But when turned off and turned back on in a short period of time, nothing. No image. Just the backlight. This seems like a very peculiar problem to me. Unfortunately, it’s only the most recent in a slew of problems I’ve been having. In fact, I had dropped it off at a local service center because of the following issues just two days ago: Just one week after the warranty period ended, my TV started having this dark column on the left (close to the center) side of the screen. It happened with no warning. A suddenly present vertical patch of darkness, focused more towards the bottom (please look at the attached picture). I still had image, though, so I ignored this for a while.But then a few day ago, I turned my TV on and it just started flickering randomly. No image, just grey to black, random flicker. This is a video of that issue. The service people were able to fix the first problem by replacing the LEDs. But after doing that they’re now facing this “The TV needs a break if you want it to work” issue. They don’t know / aren’t sure if this is still Problem #2 mentioned above, just presenting differently because the LEDs have been fixed, or if it’s a new problem entirely. But they seem to be implying it could be a problem with the panel itself, but that would cost me a bomb to replace. I really don’t want to get ripped off / tricked into spending so much money unnecessarily, so I would love to have you guys’ insight. Also, they described this problem to me over the phone. I’ll try and get footage of it when I go there in about 6 hours.
Hi, Did they say if they tried a new power board? Just wondering if as initially the LEDs were faulty, which looks about right from the image you posted then perhaps this may have also damaged the power board depending on the problem with the LEDs. In the video not all the LEDs are coming on, just some. Try the following: Turn off the TV and then disconnect the power from the TV. Remove the back cover from the TV and disconnect the cable between the mainboard and the power board. Reconnect the power to the TV. When the mainboard is disconnected from the power board and power is applied to the TV the power board is turned on to full power output. The LED backlights should all turn on full and stay on. There will be no picture because the mainboard has been disconnected. If the backlights don’t turn on and stay on then there is a problem with the power board or the LED array or the connection between the two. Measure the voltage at the LED power connector on the power board. If it is >220V DC then there is a problem with the backlights (or the connection to the backlights as the power board is trying to drive the voltage as high as possible trying to turn them on. If it is <80V DC then there is a problem with the power board. If the backlights stay on measure the voltages at the power board connector where the mainboard cable was connected. The voltage values should be printed on the power board near the connector. Check that they are as stated. If they are then there may be a problem with the mainboard. Be safety aware if you decide to try this as there is exposed lethal AC voltage on the power board when the power is connected to the TV. Do not work in the back of the TV when the power is connected if you don’t know what you’re doing. Disconnect the power before working in the back of the TV unless you’re “live” testing and you know what you’re doing.
