HDMI 2nd display "disappearing"

[mrstrong]

We tend to use a lot of "vga splitters" but in this class they have

PC-VGA out to the monitor's VGA in and

PC-HDMI out to touchscreen's HDMI in (no adapters just cables)

 

Display is set to duplicate and been fine for ages but yesterday the touchscreen went blank

all afternoon.

 

When I got to have a look in windows advanced display settings I only had display 1.

Sometimes there was a connection sound and display 2 appeared

then it disappeared again.

 

I've checked drivers are latest, tried a different HDMI port, changed cable

Tried a new user login (clutching at straws?!), thought maybe power settings

(can HDMI go to "sleep"?)

 

Been back this morning and it's working again !?

 

Any ideas, guess I could try a different PC / laptop or is it more likely to

be the screen hardware ?

[Andrew_C]

You seem not to be the only one.

 

https://www.edugeek.net/forums/windows-10/234439-pc-losing-duplicate-extend-settings.html

[SamanthaD]

If you can, try forcing the HDMI output's resolution and, more importantly, the refresh rate. We've found a number of newer laptops trying to push UHD @ 60Hz which the system just can't handle, but drop the rate to 30Hz and it's fine. Not sure if it's the display (unlikely if EDID is working correctly) or the cable (more likely - there's a lot of bandwidth required for UHD @ 60Hz!).

[Julian]

Stupid idea, but have you tried Windows + P key command.

It is a running joke, with myself and my collegue, that when a display is blank, someone has used Windows + P, to switch it off!