Had for about 5 days working great, loved It then next day no screen, it was only manufactured in march 2020. its either a black screen or no screen. My phone app picks it up and shows battery power and for hand sets too, my wifi does too, says it's on Same network as phone. I can hear the sound all the time, even sounds like I'm rolling over a button here and there with the hand controller, . Odd thing is when I hold down buttons to reset or use phone app to reset it disappears from my phone then setting it up again it asks for 5 digit code but of course I can't see it, odd it just goes past this, lets me setup wifi no problem. I can start games from my phone and it says they are now running inside headset. When I press power button I get a slight flicker. Never seen the 3 dots others get. I have a couple of tickets open on support but still waiting. I had it working great using link cable, only ran 2 apps which were Google earthvr and xplane11, both worked well.
Try pressing and holding the power button until you see an option to restart appears in the headset. I've seen the quest link driver crash and do exactly as you say, black screen no dots. A restart gets it sorted here.
Gigabyte AB350 Ryzen 2700x, 16gb ddr 4 3200, 1080ti. Z800 HMD, DK1, DK2, CV1, Vive wireless, Quest, HP Reverb. Viewsonic 1080p 3D projector ASUS 3D vision monitor. UAD Apollo interface, Yamaha studio monitors.