HDMI Ports not working

Over the past few years I've had most all of my  M4600  or other M series HDMI port refuse to put out a signal.  I've had several company visitors bring their Dell laptops in and if they are M series laptops will not communicate with our overhead projectors via HDMI. The projector simply says NO SIGNAL.  Yet on the same projector when I connect my E5450 it will project just fine.  This happens when using a TV using HDMI as well.

In all cases it SEES the projector or TV screen as a second monitor.  I've popped open the PROJECT app and told it to MIRROR the screens.  I can see the monitor add itself to DEVICE MANAGER when plugging in the HDMI cable and see it leave when unplugging it. This happens with Windows 7 and Windows 10.

I had a an old M4600's connected it to my TV.  It worked for months on Windows 10 then suddenly would no longer put out a signal over HDMI.  Again, I can see the TV by correct name in Device Manager when it's plugged in, I tell it to MIRROR or even EXTEND the desktop and nothing happens but NO SIGNAL on the TV. I pulled out an even older M4600 one that had been offline for about a year and it worked until MS did updates.  I went through the Dell updates and Windows updates and will no longer work - NO SIGNAL.  

I put a brand new fresh Windows 10 image on the first laptop (that I had been using for months) and it no longer works - with a brand new image from MS.  I tried updating the vid drivers from Dell, still no signal.  I tried drivers directly from Nvidia with the same results - NO SIGNAL.  Again, I hooked my Win 8.1 E5450 to the same TV and it projects fine.  As does an older Inspiron with Windows 10.

I cannot get any M series laptop to project out it's HDMI port on two different projectors and 1 TV, while the same TV / projectors work just fine with an E series and Inspiron series laptop.   I tried 4 different HDMI cables, ALL work with the E series and Inspiron, NONE wok with any M series laptop. 

I have no idea what's going on here.  Any ideas?