Black Screen on 13" Macbook Pro 2019/Catalina. Resetting NVRAM/PRAM, SMC does not work My wife's Macbook Pro suddenly dropped to a black screen with the power still on; keys light up, caps lock light comes on; display is clearly getting power. Holding down the power button kills power to the machine, but it does not restart.  If I hold the power button, I get the "power connected" sound you get when the AC Adapter is plugged in, but nothing else - it goes right back to the black screen.

I've tried resetting the SMC and the PRAM/NVRAM with no success. Also tried plugging in an external display - nothing.  What are my next steps? If it helps, we have another Macbook running Catalina I can use for any sort of boot disks or something.
It sounds like you were able to restart, however I have experienced a similar black screen, which is some kind of hardware bug on the Macbook Pro. The screen will go black, but the computer is still running. Sometimes the screen will come back on its own; sometimes I can Command-Tab through programs and quit (I can see that I'm switching via the Touch bar); and sometimes I must restart. Over time, I have discovered that Google Chrome is the culprit, but exactly what is happening remains a mystery.

My thought in your case is that perhaps the processes that are causing this issue are resuming through restart. But obviously you'd see the Apple in this case, and it sounds like you're not seeing anything at all.

So maybe your graphics card has failed.