windows 7 - Laptop screen periodically turns on and off while using external monitor

08
2014-07
  • Ismail Kuruca

    When I connect my laptop to my TV via HDMI cable the following list of events occurs;

    1. Laptop screen goes black
    2. Windows "something plugged in" sound plays
    3. After approximately 5 seconds windows "something unplugged" sound plays
    4. Laptop screen comes back on
    5. After approx. 2 seconds; start from STEP 1.

    A little background on the problem;

    The first time I hooked up my laptop to the TV; everything was normal except for the resolution which was a little off, so I changed the resolution from 1920x1080 to 1920x1200. After I changed and confirmed the new settings; this problem started to occur.

    I believe its related to some saved resolution information about the device in some configuration file or registry and when I connect it, windows automatically tries to set its resolution to 1920x1200 which causes the connection to be reset by TV (thus unplug.wav and laptop screen coming back on) then re-try it all over.

    List of things I've tried so far;

    1. Tried the same HDMI cable on other sources (just to make sure it works properly)
    2. Connected my laptop to a desktop monitor. (my TV is wide screen 46", monitor is a typical 22")
    3. Removed and reinstalled my video card driver (7670M Radeon)
    4. Installed a dummy display device so that when I plug my TV it wouldn't automatically tries to connect with it which would allow me to change its default resolution. But the combobox was disabled at my laptops resoulution (1366x768).
    • Answers
  • Ismail Kuruca

    I finally managed to solve my problem, albeit not completely.

    CTRL + ALT + F3

    is your friend!. With this key combination, I've been able to activate my primary display device (my laptop monitor) instantly. So the instant my laptop screen goes black, I used this combination to turn it back on, and change the secondary device's resolution.

    Now I can project my display to both screen or extend it. I still can't use 'projector only' option but it's acceptable.


    • Related Question

    windows 7 - 2 monitors + HDMI LCD Screen
  • Nick Udell

    I currently have an nVidia GTX 480, with two DVI ports and one HDMI. I have the two DVIs plugged into 1680x1050 resolution monitors and the HDMI into a 1080p HD TV.

    Currently Windows7's screen resolution tool will only let me have one monitor + TV or 2 monitors and no TV showing extended desktops at a time. Is this a software or hardware limitation?

    If I get better multi-monitor software will I be able to extend my desktop across all three screens?


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  • Simon Sheehan

    You can connect 3 monitors, but one will be disabled. The point of having the 3 ports is to give you options, so you can choose between using DVI or HDMI. Here's a quote from a thread on the NVIDIA forums when someone asked about multiple monitors on the GTX 480

    For graphics cards which have a single GPU onboard like the Geforce GTX 480 or 470, only two displays can be active at the same time even if the card has three physical monitor connectors. Some cards like the older version of the Geforce GTX 295 have two GPUs onboard and three display connections, two DVI and one HDMI. The first two ports, the two DVI ports are connected to the first GPU and the HDMI port is connected to the 2nd GPU. So in this case, three monitors could be supported as long as the card wasn't set to "multi-GPU" mode. But for pretty much every NVIDIA graphics card, you will only be able to activate two monitors at the same time.

    This is a hardware limitation. I suggest purchasing a cheaper card like a GT 220 and putting that in to add more monitors.