My nephew hopes to connect his GA402 laptop to his HDTV using the HDMI port. The HDTV shows nothing but it is clear that it senses a connection. When the HDMI connection is removed the TV reports no connection.
Connecting my laptop instantly show a display on the HDTV so the cable is fine and the TV is fine. I suspect that the GA402 is producing 4k, which the HD TV is not capable of displaying.
When connected to a 4k TV, there's no picture. If I am correct in my suspicion above, this likely IS a cable issue because I'm pretty sure the HDMI cable isn't capable of transmitting 4k signals. I'm away from home trying to help him so I don't have access to my stash of tech goodies, and I'm not familiar with this laptop, having only seen it for the first time when he asked me for help.
A couple of questions come up:
Does this laptop produce 4k on the HDMI port as the default output?
How can I configure the HDMI port to produce HD? That is to say, NOT 4k, just good old 1920x1080.
I understand that there are other ways to accomplish this, primarily using USB-C ports, but that would require hardware that is not on hand, so I was hoping to focus on what we can do via HDMI
If the TV is only a HDTV, it should be able to communicate that to the computer so the computer does not even try to send 4K signal.
The GA402 has a MUX switch, though the HDMI is connected exclusively to only one GPU. That means there may be issues if the laptop is being run in Eco mode (or whatever the name is in Armoury Crate where the dedicated GPU is turned off). I suggest checking that both GPUs are enabled (Windows or Optimized modes).
Another simple thing to check is whether Windows is detecting the new screen in the Windows settings. If it is, it may be a case of projection being set to Main Screen Only, meaning secondary screens are not used. Win+P or the Settings app will help sort that out.
A third simple thing to check is whether the graphics drivers are up to date. The GA402 should be all AMD so if AMD Adrenaline is installed, checking the MyASUS app for updates should make sure you have the latest ASUS-approved drivers installed. If AMD Adrenaline is not installed, I recommend checking the MyASUS app for all drivers (there is a checkbox where additional drivers can be updated) and getting the AMD drivers through there.
Similar steps are described in the ASUS support documents.