Chosen Solution
When I connect the Mac Mini to a monitor or my Epson projector the display say " No Signal" I have tried a VGA adaptor in the monitor port and HDMI cord. Both times the same results.
Sounds like a bad video card. The video processor in all of these systems is soldered in place and cannot be removed, changed or upgraded. That would mean a logic board replace… it might be cheaper to just get an entire new machine. If this answer was helpful please remember to return and mark it Accepted.