Visio P75Q9-H61 has no picture. The t-con board is clicking?

@ftech T-con board in general do not click. There is no relay etc. that could click. There are a few coils that could give you whine. You need to let us know what you have checked so far. The no picture is a T-con board failure possibility, but there are many other more possibilities that do need to get checked. Otherwise, you are just going to change board after board, and I would hate for you to waste your money on boards you may not need.

First you want to go ahead and see if this is a backlight issue since you did not mention if you have sound on your TV. In a darked room, and with the TV on (preferable a channel where you have sound, shine a flashlight beam at an angle against the screen. See if you can make out shapes/silhouettes. If so, it is your backlight that is out (possibly a backlight array issue). Next you want to remove the back cover from your TV. Now unplug the main board cable from the power board. On Samsung power supplies, this will turn the backlight on. In the sheet metal that covers your panels, are multiple small holes. Use those holes to monitor if the backlight comes on. If it does not, it most likely is your power board. Now here is where it gets interesting. Your TV appears to have an LED driver board. That has components that could click and if that board fails, you will have no backlight. If the last test works and your backlights turn on, plug the main board back into that power board. Now you will have to measure the voltages on the power board connector where the cable from the main board plugged into. You are mostly interested in the BKL_On voltage. Those voltages are silkscreened onto the power board. Let us know what you are getting. If you want to check the t-con board, do one test. There is a fuse labelled F101 next to the left-hand side flat ribbon connector. Use a multimeter on that to check it for continuity. After that measure the voltage on that fuse. You should get no less than 12V on that.

Like my esteemed colleague @andrewsawesome already mentioned in his comment, it is always helpful if you post some good pictures of your boards with your quetion. That way we can see what you see. Adding images to an existing question - iFixit Repair Guide