Update:  1.  Updated bios to 1.11.0.  2.  Exited bios menu, saw Dell logo, then just black screen.3.  Plugged in HDMI to external monitor, both internal display and external monitor showed the screen.4.  Unplugged HDMI, internal display stayed on.  
Hello Dell community. Yesterday I received a precision 7560.  When run in discrete graphics mode, (hybrid mode turned off), the screen either a) works for some time past login and eventually goes black, or b) does not make it past the dell logo screen and remains black. This is a completely clean system with no software installed.  I am not connected to any peripherals.  userbenchmark has returned excellent results, so my GPU is certainly working.  Why does discrete graphics mode make my screen black? This occurred both out box and after all updates had been installed.  Drivers are updated.   Specs: i9-11950HRTX A300064 GB ddr4 3200 MHz RAMWindows 10   < Private Express service code removed.TOS73>
Brand New Precision 7560, black screen in discrete graphics mode