I also just purchased a TCL Roku TV. I also have DirecTV hooked up to it. I haven't had any issue beyond having to wait till almost 4am on black Friday to activate the TV because Roku was having an outage.
I did notice one thing yesterday that might help you. All I have connected to the TV, which is a 65" are a DirecTV genie mini receiver and a sound bar that I bought with the TV on Thanksgiving night. I share my home with my mom, the first thing I did when I was able to get the TV activated was I immediately programmed the DirecTV remote to work the TV and sound bar in an attempt to make things easier for her to navigate. She shut the TV off yesterday, but when she turned it back on, the input for HDMI 1 (DirecTV) said no signal. I went and looked and she had something blocking the mini receiver, which is why when she turned the TV on, the receiver didn't also turn on. I moved what was blocking it and hit the small blue DirecTV logo button and it came on with no issue.
Depending on whether you have a mini receiver hooked up or you have the main DVR hooked into the TV, you might need to hit the logo button. If you don't, it will show it booting up, but if it wasn't on before that process starts, it will give what you're describing with the boot up then black screen. I also suggest taking advantage of the ability to custom label your inputs on the home screen. I labeled DirecTV for the one HDMI port that I have it hooked into so it's relatively easy for my mom to find.
I've been very impressed with TCL so far that I'm already thinking of upgrading another one of my TV's once I can afford to. Excellent quality, feel like I have a mini theater now.
