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Repair guides and support for your Samsung TV.

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After lightning strike, "samsung smart tv" blinks on screen

My Samsung UN65MU8000F TV was connected to cable TV box when lightning struck. TV went to displaying “Samsung Smart TV” on screen for about a second every 3 or 4 seconds and nothing else. Remote would not turn off or on or anything else (like allow changing source input). Cable box also lost its HDMI output but was replaced and new one works with other TV. Upon suggestion of cable guy, replaced “one connect” box with used one bought from ebay - no joy, same problem. Next took back off TV and replaced main control board with part from on line parts supplier - same result, no change. Any one know for sure what is wrong and how I can repair it?

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Hi @mike_the_tiger ,

Any power surge would have to pass through the power board before getting to the mainboard. Given that the TV was on at the time (is this correct?) there may have been two problems i.e. mainboard and power board.

With the TV on, check if the voltages from the power board (BN44-00912A?) to the mainboard at connector CNM803 are as shown on the board next to the connector.

Be safety aware if you try this as there is exposed lethal AC power close to where you will be testing on the board.

If your area is prone to lightning strikes or power outages, it may be prudent to invest in a quality power surge protector and connect your devices through it to prevent or at least minimize any damage.

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Jayeff,

Thanks for input.

Yes, TV was on when lightning hit.

Yes, Power supply is BN44-00912A and appropriate connector CNM803.

Checking voltages on back of plug with everything connected, both Vamp and A13V would be at the spec'd 12.8 volts for a while and then go down. Period of fluctuation was about the same as backlighting or "Samsung Smart TV" display on front. Is fluctuation normal?

Additional info - a second 40" TV was connected to a remote cable box and it also had HDMI failure and remote box failure. That TV would at least work on over the air signals - yet to repair the HDMI part of it (hoping to get big screen working before football season). This leads be to believe that glitch came in on cable system, not power and that surge protector that didn't also work on cable coax input would not have been sufficient. Thoughts? Next steps?

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@mike_the_tiger

You have replaced the mainboard so suspect that next it will be the power board even though the voltages appear to be OK but it may directly feed other parts (backlight?) as well or maybe it can't sustain the output.

With regards to a power surge through the cable feed, you can buy surge suppressors for that as well. Usually they're found built in with the better quality powerstrips (examples only) where not only are the power outlets protected you can run the signal cable in and out of the power strip so it is protected as well.

Of course this depends on the type of cable input.

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Jayeff,

Many thanks. The power supply board it was. That to me is strange as I thought the "one connect" and main board as more likely suspects and now have two spares of those, but the power supply change out did indeed restore my lovely picture.

Thanks again.

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Thank you for this question and the replies. I had the exact same problem and replacing the power supply fixed it!

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