I found this post because I have recently experienced the exact same issue with my BeoVision 7-55 Mk2. I don’t know whether your problem has been solved since you posted this. The horizontal black line on my BV appears approximately four lines from the bottom of the screen. I have tried unplugging the power cable from the wall outlet and waiting for 10 minutes. Then the horizontal line disappeared when I switched the BV on again, but it has reappeared from time to time. I fear it may get worse or become permanent. I am wondering whether it has something to do with the heat. UPDATE: The issue with the black horizontal line appears approximately 10–15 minutes after the BV is switched on. It then comes and goes, but within the next 20 minutes, it remains permanently visible until the BV has been switched off for several minutes “to cool down”. Even if I restart the BV (i.e., power it off with the remote and then immediately power it back on), the black line is still present. I have also tried switching between different input sources, but the black line does not disappear in this regard. I may have to contact a B&O repair service and ask for a price and whether they can fix this. I love my BV 7-55 too much to just discard it. Kind regards, Michael