Thunderbolt to HDMI don't work. Only VGA

[Tiquisson]

Hey guys!

I have a problem here that's driving me mad (and sad, of course).

I'm trying to connect my Macbook Pro Mid 2012 with a thuderbolt to HDMI adapter to a monitor and my computer dont recognize it. I tried with a lot of cables, monitors and adapter and nothing works. The Mac only blink the screen when i connect it.

The thing is: It works with a thunderbolt do VGA adapter normaly, i the same port!

Can someone tell me whats going on?

Many thanks!

 

[treekram]

So the adapters you're using are almost certainly using the Displayport signal, not the Thunderbolt signal, so they should be called MiniDisplayport-to-HDMI or MiniDisplayport-to-VGA adapters. This is just a matter of terminology.

If your monitor has a resolution greater than 1980x1200, you likely need an "active" adapter so search for "mini displayport to hdmi active adapter" and try one of those if you haven't done so already. I have the 2012 non-Retina MBP with the (non-active) Amazon Basics MDP-HDMI adapter, it has no problem with our TV or my 1920x1080 monitor but nothing appears on my 2560x1440 monitor.

 

[Tiquisson]

So the adapters you're using are almost certainly using the Displayport signal, not the Thunderbolt signal, so they should be called MiniDisplayport-to-HDMI or MiniDisplayport-to-VGA adapters. This is just a matter of terminology.

If your monitor has a resolution greater than 1980x1200, you likely need an "active" adapter so search for "mini displayport to hdmi active adapter" and try one of those if you haven't done so already. I have the 2012 non-Retina MBP with the (non-active) Amazon Basics MDP-HDMI adapter, it has no problem with our TV or my 1920x1080 monitor but nothing appears on my 2560x1440 monitor.

Treekram, thanks for the answer!

I didn't know about those two types of adapters! I will find one of these "active" ones and see whats happens and I will update it here when I get it!

But one more information: The monitors that I'm trying to connect (and failing) with these "non-active" adapters is on a 1920x1080 resolution.

 

[Fishrrman]

Just wondering...

It works using VGA?
Is the picture quality OK?
Is the resolution where you want it?

If everything works OK using VGA, why not just use that?

 

[Tiquisson]

Just wondering...

It works using VGA?
Is the picture quality OK?
Is the resolution where you want it?

If everything works OK using VGA, why not just use that?

Hi fisherman!

Hahaha, I know it look simple!
But the monitor in my house don't have the VGA port to connect. Only the HDMI

 

[robvas]

What monitor is it, exactly?

I have an older 21" Acer monitor that will NOT work over HDMI but works just fine on VGA. Then I have another (different year) MacBook where it works fine over HDMI. Mysterious.

 

[Tiquisson]

What monitor is it, exactly?

I have an older 21" Acer monitor that will NOT work over HDMI but works just fine on VGA. Then I have another (different year) MacBook where it works fine over HDMI. Mysterious.

I'm not sure what is the model of my house's monitor. But here in my workplace, I have a LG 23MP55HQ Full HD 23" with this problem: The VGA port works and the HDMI not (only in my mac)

 

[treekram]

A non-active MiniDisplayport-to-HDMI adapter should work with a 1920x1080 monitor, like the LG 23MP55HQ. It's possible that an active adapter will work where the non-active didn't but I think that the chances that something else is going on is more likely.

A couple things to try is to see if there are monitors at work (or home) where you can plug into your MiniDisplayport port (without the need for an adapter) and see if that works. If an Apple Store is convenient you can go there to have them see if your port is working properly.

 

[Tiquisson]

A non-active MiniDisplayport-to-HDMI adapter should work with a 1920x1080 monitor, like the LG 23MP55HQ. It's possible that an active adapter will work where the non-active didn't but I think that the chances that something else is going on is more likely.

A couple things to try is to see if there are monitors at work (or home) where you can plug into your MiniDisplayport port (without the need for an adapter) and see if that works. If an Apple Store is convenient you can go there to have them see if your port is working properly.

Hi again Treekram!

I tried with a cinema display, which has a thunderbolt cable, and it worked!

Really don't know whats is going on...

 

[treekram]

Hi again Treekram!

I tried with a cinema display, which has a thunderbolt cable, and it worked!

Really don't know whats is going on...

So this is important - if it is an Apple Cinema Display, it would have be the one with the MiniDisplayport input, in which case, your computer is fine and it's outputting the correct signal, it's likely the MiniDisplayport-to-HDMI adapter that's the issue. If you connected to an Apple Thunderbolt Display - that uses a Thunderbolt signal from your computer, which is not the same as the signal used when connected to an Apple Cinema Display. Either of the later Cinema Displays or the Thunderbolt Display will connect to the same port on the MBP, but the signal they use is different.

So check the System Preferences -> Display. If it is the Cinema Display, you need to try a different MDP-HDMI adapter. You might as well get an active one as it's only a few dollars more and it will work with higher resolution monitors if you need to do so in the future. If it is the Thunderbolt Display, it's possible that there's something wrong with the computer when it's outputting the Displayport signal, although that's unusual seeing that the MDP->VGA adapter works.

 

[Tiquisson]

So this is important - if it is an Apple Cinema Display, it would have be the one with the MiniDisplayport input, in which case, your computer is fine and it's outputting the correct signal, it's likely the MiniDisplayport-to-HDMI adapter that's the issue. If you connected to an Apple Thunderbolt Display - that uses a Thunderbolt signal from your computer, which is not the same as the signal used when connected to an Apple Cinema Display. Either of the later Cinema Displays or the Thunderbolt Display will connect to the same port on the MBP, but the signal they use is different.

So check the System Preferences -> Display. If it is the Cinema Display, you need to try a different MDP-HDMI adapter. You might as well get an active one as it's only a few dollars more and it will work with higher resolution monitors if you need to do so in the future. If it is the Thunderbolt Display, it's possible that there's something wrong with the computer when it's outputting the Displayport signal, although that's unusual seeing that the MDP->VGA adapter works.

I checked it here an it is a Thunderbolt display, not a cinema display! (i didn't know there was two types).

So, as you said, the problem should be the MDP signal...
But, as the MDP>VGA works, it should be a software thing, right? Or you think it is a hardware problem?

 

[treekram]

I checked it here an it is a Thunderbolt display, not a cinema display! (i didn't know there was two types).

So, as you said, the problem should be the MDP signal...
But, as the MDP>VGA works, it should be a software thing, right? Or you think it is a hardware problem?

I think at this point the easiest thing to do is try an active MDP-HDMI adapter. It shouldn't be software because the computer, when connected via MDP->VGA adapter, thinks it's putting out a Displayport signal. Now it's possible, but very unlikely, you have a Thunderbolt->VGA adapter but I don't think those exist and it would probably be in at least the $40-$50 range in cost.