Can't use TV as a monitor for Windows 7 PC

27 Jan 2008
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Llanfair Caereinion, Nr Welshpool
United Kingdom
New windows 7 desk top idea was to use it to watch films which my blueray player fails to recognise.

So switch on and the windows splash screen comes up. It then goes black and windows start up music plays but screen remains black. Pressing on/off button and holding in until switches off and restart I get safe mode option. Selecting safe mode boots and screen works OK but no sound.

Reboot again and splash screen and no picture but sound works OK hot swap the monitor cable to a small monitor and monitor works but whole idea was to watch the videos on the large TV screen.

I am sure it's setting which are wrong but as to if TV or computer not a clue. TV works with another PC but that one has a green cast on the screen.

Any ideas please.
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Read your TV manual. Check the resolutions that the TV will support. Cross check those with the resolutions that the monitor will support. Before swapping to the TV, set the graphics resolution to one of the common modes.
I did try a manual set to lowest it would go to and no luck. I think is a buy a new card job or USB to VGA or USB to HDMI adaptor. Loads of USB sockets and that means I could also use other computers the same way. I am looking at
this advert which seems to do both.

With HDMI already using both inputs one for bluray one for sky but VGA input is free. I have not got HD eyes so never really worried about HD TV.
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That link goes to a Display Port adapter, as it states.
Nothing to do with USB, which, unfortunately, won't carry video signals.
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Would you please be a little more specific about the hardware you're dealing with? It's hard to have any idea what's wrong when all we know is you have some TV and some PC.

Nothing to do with USB, which, unfortunately, won't carry video signals.

That's odd. I have USB video input and output devices. But it won't carry video? How strange..
You should be able to hook the display port to an HDMI input and it should work - we've a few customers at work who use large LED TVs as marketing displays. But as mentioned, if the computer and TV can't agree on a resolution that the TV can display and the PC can produce then you'll get nothing. It's not too uncommon for some TVs to support limited modes (basically TV modes only). Something else we've found is that some TVs are "reluctant" to display a "true" image (ie one that hasn't been rescaled and cropped) - in one case we found that 1 TV gave different results depending whether we connected to the motherboard HDMI or the add-on HDMI card :confused:
It may even be as simple as the TV firmware has bugs which don't show up when fed with "TV" signals, but which do when connected to a PC. Eg, if the TV advertises it can do a mode which it actually can't display - then the PC may switch to that mode (they tend to go to the highest resolution & scan frequency supported), the TV looks as what it's being sent, decides it can't display it, and goes blank.

If you have another PC, try setting up this one for remote control (eg by RDP) from your other computer. Then you can connect to it and see what settings it's trying to use, and manually alter the display settings until you get a picture.

Related topics crop up on the MythTV mailing list from time to time. Sometimes people have to force a particular display mode to make things work - relatively simple in "X" as you can specify a modeline for a monitor.

On USB devices. Well yes they work, but do the maths. An uncompressed video signal can be several gigabits/sec (1920*1080*60p*8bit (24bit for 3 colours) requires just shy of 3Gbps) - USB2 is less than 1/2 a Gbps (and after overheads is less. To show video, it either needs compressing and decompressing (CPU load and loss of detail), or the resolution suffers, or the refresh rate suffers.
The fact you can see the Windows splash screen on the TV when booting rules out a number of connectivity issues at both ends. Basically, it's working until you get into Windows proper.
Ergo, the issue is with Windows.

Connect the TV as a secondary display to your PC / Laptop, go into Windows display properties/ Screen Resolution and make sure the TV/ second display is detected, is enabled, and check the settings for Multiple Displays.
It's even possible the TV is active and displaying, just showing a black desktop background with no icons on it.
Don't feel daft if it is, you wont be the first person to have done this :D
It works in safe mode, so it's possible to get a picture from your computer to the TV. The most likely reason you don't get sound in safe mode is that windows won't be playing the sounds in that mode.

As others have mentioned, you most likely need to set the video card to a mode that the TV supports. At the moment it may be set to too high a resolution, or too high a refresh rate.

It might be worth setting the video resolution in safe mode. If I remember correctly that will only let you set the very basic settings which should then be visible.

If you can get any kind of picture at all with windows booting normally, you can then just try a few settings. Windows always waits 15 seconds for you to confirm any screen settings change, so if you change to something that means you don't get any picture on screen, just wait 15 seconds and it'll go back to how it was before.

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