Strange PC behavior when connected to an HDTV

Doublej · « **on:** 24 Nov 2016, 01:47 am »

I have a Dell Optiplex running Windows 7. I have two monitors connected to it. First is an Asus monitor connected using DisplayPort. This is my main monitor.

The second monitor is a Samsung UN65H7150 HDTV that is only occasionally turned on. However, even with the HDTV power off, as long as the HDTV is connected to the compute via HDMI and the HDTV is plugged into the wall, the Dell thinks the HDTV is turned on and automatically uses it as a second display. This of course wreaks havoc with the cursor.

What do I need to change so that when the Samsung is powered off the Dell does not think it is turned on? It seems like there is some setting on the HDTV related to HDMI configuration that needs to be changed. .

FullRangeMan · « **Reply #1 on:** 24 Nov 2016, 01:51 am »

W7/10 by default think user will want bigger monitors as main monitor.
You have to set one monitor as main at the Customize your Display screen or equivalent in W7.

Doublej · « **Reply #2 on:** 24 Nov 2016, 01:59 am »

Quote from: FullRangeMan on 24 Nov 2016, 01:51 am

W7/10 by default think user will want bigger monitors as main monitor.
You have to set one monitor as main at the Customize your Display screen or equivalent in W7.

I did. I have the Asus set as the main monitor and it is displaying as the main monitor all the time no matter what is happening with the TV.

FullRangeMan · « **Reply #3 on:** 24 Nov 2016, 02:18 am »

Quote from: Doublej on 24 Nov 2016, 01:59 am

I did. I have the Asus set as the main monitor and it is displaying as the main monitor all the time no matter what is happening with the TV.

OK, when you connect the TV power cord on mains wall this monitor already on and send signal to the W7 he is there and for video card its a monitor, what actually it is.
They call it plug and play.

JRace · « **Reply #4 on:** 24 Nov 2016, 02:38 pm »

Look in the HDTV for any HDMI settings related to:
CEC, power sense, etc.

This allows HDMI devices to be controlled by each other, and to turn on and off with each other.
This would create an "always on" connection from the HDTV to the PC as the HDTV is waiting for a control signal to come down the HDMI cable.

Wayner · « **Reply #5 on:** 24 Nov 2016, 02:55 pm »

Even though the TV is "off", it is still on, or at least parts of it are still on. The parts that are on are for remote sensing and things like that. I'm pretty sure, the HDMI is sending and looking for an on command from a source, and the PC is doing a handshake with it.

I'm also pretty sure that in the TV's menu, there is a command to disable automatic turn on, when it senses a handshake from a source component. Look for this in the menu, turn it off, and the TV will stop doing what its doing.

Wayner

FullRangeMan · « **Reply #6 on:** 24 Nov 2016, 06:41 pm »

As said above when the TV power cord is connected to the mains wall the TV power supply becomes on to waiting a possible remote control signal.
Difficult to modify it or anything in the PC.

Wayner · « **Reply #7 on:** 24 Nov 2016, 07:10 pm »

It's in the TV's software. Many, if not all TVs nowdays have signal sensing "turn on" features. I've been involved in many home theater installs and have seen this many times. It's not the PCs problem at all.