Can't duplicate screen with HDMI to VGA adapter

Live at Three

I've got a new laptop which doesn't have a VGA port. I bought a HDMI to VGA adapter so that I can use it in work for a projector. On some projectors the duplicate screen function doesn't work, but the extend screen does. Extending the screen is very awkward. Sometimes when I press duplicate I will see the screen flash up on the projector for a split second, but then disappear.

- I've tried updating graphics driver.
- Windows 10
- Hp Pavillion
- Works fine on some projectors in work
- Old laptop worked fine with VGA to VGA cable.
- HDMI adapter also has an audio out, which works fine

This is doing my head in. Any suggestions please?

mordeith

Live at Three wrote: »

I've got a new laptop which doesn't have a VGA port. I bought a HDMI to VGA adapter so that I can use it in work for a projector. On some projectors the duplicate screen function doesn't work, but the extend screen does. Extending the screen is very awkward. Sometimes when I press duplicate I will see the screen flash up on the projector for a split second, but then disappear.

- I've tried updating graphics driver.
- Windows 10
- Hp Pavillion
- Works fine on some projectors in work
- Old laptop worked fine with VGA to VGA cable.
- HDMI adapter also has an audio out, which works fine

This is doing my head in. Any suggestions please?

What type of adapter? I've heard they can be very unrelliable

ED E

Its a resolution issue.


With a normal cable the computer asks the screen for what res it supports using EDID. That adapter you're using blocks those messages. Subsequently when you duplicate display the laptops own screen res is used for both displays. If the projector cannot handle such a res it won't understand the signal it receives and thus goes blank.

1. Take the cable out
2. Set the desktop to 1024x768 or 1280x720 (right click, display settings)
3. Connect the cable
4. Duplicate

It should then work. Expect the image to look pretty crap on your laptop itself.

Live at Three

ED E wrote: »

Its a resolution issue.


With a normal cable the computer asks the screen for what res it supports using EDID. That adapter you're using blocks those messages. Subsequently when you duplicate display the laptops own screen res is used for both displays. If the projector cannot handle such a res it won't understand the signal it receives and thus goes blank.

1. Take the cable out
2. Set the desktop to 1024x768 or 1280x720 (right click, display settings)
3. Connect the cable
4. Duplicate

It should then work. Expect the image to look pretty crap on your laptop itself.

This sounds good, the old laptop used to automatically change the display to a blocky resolution when protecting. Haven't had the chance to try it yet. Will let you know.

Live at Three

ED E wrote: »

Its a resolution issue.


With a normal cable the computer asks the screen for what res it supports using EDID. That adapter you're using blocks those messages. Subsequently when you duplicate display the laptops own screen res is used for both displays. If the projector cannot handle such a res it won't understand the signal it receives and thus goes blank.

1. Take the cable out
2. Set the desktop to 1024x768 or 1280x720 (right click, display settings)
3. Connect the cable
4. Duplicate

It should then work. Expect the image to look pretty crap on your laptop itself.

Unfortunately this doesn't work. Note that "extend" and "second screen only" options work fine.

Live at Three

ED E wrote: »

Its a resolution issue.


With a normal cable the computer asks the screen for what res it supports using EDID. That adapter you're using blocks those messages. Subsequently when you duplicate display the laptops own screen res is used for both displays. If the projector cannot handle such a res it won't understand the signal it receives and thus goes blank.

1. Take the cable out
2. Set the desktop to 1024x768 or 1280x720 (right click, display settings)
3. Connect the cable
4. Duplicate

It should then work. Expect the image to look pretty crap on your laptop itself.

This doesnt work unfortunately. Note that 'extend screen' and second 'display only' options work fine.

I have noticed though that when I change the resolution to lower, then connect the adaptor, the laptop screen blinks black and comes back on again reading the original 1366 x 768 resolution. If I could stop it from automatically doing this I might be able to work it.

Live at Three

Live at Three wrote: »

This doesnt work unfortunately. Note that 'extend screen' and second 'display only' options work fine.

I have noticed though that when I change the resolution to lower, then connect the adaptor, the laptop screen blinks black and comes back on again reading the original 1366 x 768 resolution. If I could stop it from automatically doing this I might be able to work it.

Advanced display settings say that display 1 resolution is 1366x768 and 60 Hz refresh and display 2 VGA display is 1024x768 and 59 Hz refresh. It asks for administrator access if I try to change refresh rate.

coylemj

I'd agree with poster ED_E in post #3 that it's a resolution issue but I'd suggest that you check the projector's manual to see which resolutions and refresh rates are supported and try that setting. But the HDMI port on your laptop may be expecting a confirmation signal from the external screen or projector that it supports the resolution of the signal being sent out from the HDMI port and as you are using a digital to analog converter, it may not be getting any signal back so the laptop HDMI port is rejecting the 'device' at the end of the cable.

Live at Three

Someone in work gave me a loan of an adapter that cost almost 100 euro. It worked!

My own cost around 20 euro...

ED E

Live at Three wrote: »

Someone in work gave me a loan of an adapter that cost almost 100 euro. It worked!

My own cost around 20 euro...

Active vs passive. One has "smarts" in it, kinda like a tiny graphics card, the other just crosses some wires together.