I just got an A10 7890k for a new PC build. I don't have a discrete GPU for this build and was hoping to use the integrated graphics.
I've installed all the components but when I power on the system there is no output to my display (i've tried an HDMI display and DVI) and so I don't know if the system is reaching the BIOS or POSTing and just not displaying, or if the system is failing to POST or reach the BIOS.
HDMI will work without a OS. I suggest you clear CMOS to see if the on-board is somehow disabled. Either that or find a old, known good pcie gpu or even a pci gpu and try it.