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usagora

macrumors 601
Original poster
Nov 17, 2017
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I'm experiencing an odd issue here. When I connect my MBA M1 to my Epson 485W projector via HDMI using the (not-so-cheap) Apple USB-C Digital AV Multiport Adapter, I'm experiencing this:


I've tried restarting (projector and MBA) and using a different HDMI cable. I've also tried with another Epson projector with the same result. Here's the weird thing, though. It works perfectly fine with my 60" LG 4K TV using the same HDMI cables. So this would indicate it's neither a faulty adapter nor faulty cable. So you'd conclude it must be something wrong with the HDMI bus on the projector, right? No, because it works perfectly fine with both an Apple TV and my 2012 MBA using an HDMI to TB2 adapter. So the only thing I can think of is it's some sort of incompatibility with the HDMI bus on Epson projectors and the HDMI-to-USB-C adapter. Is there something unique to HDMI bus on a projector vs. a TV that would be causing this?

FWIW, I'm also connecting to the same projector via VGA using the Apple USB-C VGA Multiport Adapter and it works flawlessly.

I've just ordered this Anker USB C to HDMI Adapter and will report back if I have the same issue with it. If I DON'T, then I would be wondering if it's an issue of single vs. multi-port adapters when hooking to a projector.

EDIT: Here's another interesting experiment I just did. I have both a VGA-to-HDMI adapter (third party) and a HDMI-to-TB2 adapter (third party). When I connect the projector to my MBA M1 using a VGA cable, the VGA-to-HDMI adapter, and the Apple USB-C Digital AV Multiport Adapter, I get no video signal. However, if I connect the projector to my 2012 MBA using a VGA cable, the VGA-to-HDMI adapter, and the HDMI-to-TB2 adapter, I get a video signal. So strange...
 
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usagora

macrumors 601
Original poster
Nov 17, 2017
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Anyone have any ideas? Posted this same thing on another Mac forum, and someone suggested maybe I needed to buy an adapter that was specifically Thunderbolt 3 (with the lightning bolt) and not just USB-C because TB3 is a higher-spec. But that doesn't explain why the Apple USB-C Digital AV Multiport Adapter works with my 4K TV. Why would a WXGA (1280x800) projector require a higher spec than a 4K (3840x2160) display device? And the Apple adapter specifically says it's for connecting to TVs or projectors on Apple's own website. They don't even sell an HDMI-to-TB3 adapter (only this third-party dock that is way overkill). SURELY someone on this forum is connecting their TB3/USB-C-equipped Mac to a projector successfully?
 
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joevt

Contributor
Jun 21, 2012
6,840
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Only thing you can do is change adapters and cables. Or add some other stuff between the M1 Mac and the projector like one of these:
- HDMI repeater
- A Thunderbolt dock
- A USB dock

A Thunderbolt dock might be useful because the dock recreates the DisplayPort signal from the Thunderbolt data. If the DisplayPort signal from the M1 Mac is weak, then this could fix it, as long as the Thunderbolt signal is able to make it to the dock.

A USB dock uses the DisplayPort signal from the M1 Mac directly so it might not be as useful in that case.

The DisplayPort signal might be fine. Maybe there's a problem with power to the adapter. Maybe a Thunderbolt dock or USB dock can help with that.

An HDMI repeater won't help if the problem is between the M1 Mac and the adapter. Actually, you've shown that the adapter can work with a different display so maybe the problem is the HDMi part of the signal. An HDMI repeater might fix that.
 
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usagora

macrumors 601
Original poster
Nov 17, 2017
4,869
4,451
Only thing you can do is change adapters and cables. Or add some other stuff between the M1 Mac and the projector like one of these:
- HDMI repeater
- A Thunderbolt dock
- A USB dock

A Thunderbolt dock might be useful because the dock recreates the DisplayPort signal from the Thunderbolt data. If the DisplayPort signal from the M1 Mac is weak, then this could fix it, as long as the Thunderbolt signal is able to make it to the dock.

A USB dock uses the DisplayPort signal from the M1 Mac directly so it might not be as useful in that case.

The DisplayPort signal might be fine. Maybe there's a problem with power to the adapter. Maybe a Thunderbolt dock or USB dock can help with that.

An HDMI repeater won't help if the problem is between the M1 Mac and the adapter. Actually, you've shown that the adapter can work with a different display so maybe the problem is the HDMi part of the signal. An HDMI repeater might fix that.

But what I keep coming back to is why would I need to jump through any of those hoops to get this to work with a 1280x800 projector when the SAME adapter and SAME HDMI cable has a good enough video signal from the MBA to drive a 60" 4k display? Seems to me it's not the quality of the signal but rather something on the projector HDMI-bus end that's not playing well with HDMI signals coming through the adapter and/or the TB3 bus.

Well, the Anker HDMI-to-USB-C adapter arrives today, so the results of that test will be very telling. I'll post an update when I know.
 

strau

macrumors newbie
Nov 8, 2021
1
0
Did you solve your problem? I experienced the same.
I have an Apple USB-C Digital AV Multiport Adapter and I used it to connect my new Macbook Air (2021) with two different projectors. In both cases I did not succeed. In contrast, I used the same adapter to connect a couple of displays (Acer and Asus) and all worked perfectly.
Another strange thing: a friend of mine gave me another Apple USB-C Digital AV Multiport Adapter, and the connection with one of the projectors worked fine.
What's the problem??
 

usagora

macrumors 601
Original poster
Nov 17, 2017
4,869
4,451
Did you solve your problem? I experienced the same.
I have an Apple USB-C Digital AV Multiport Adapter and I used it to connect my new Macbook Air (2021) with two different projectors. In both cases I did not succeed. In contrast, I used the same adapter to connect a couple of displays (Acer and Asus) and all worked perfectly.
Another strange thing: a friend of mine gave me another Apple USB-C Digital AV Multiport Adapter, and the connection with one of the projectors worked fine.
What's the problem??

As mentioned in post 5, I purchased an Anker USB C to HDMI Adapter and it worked perfectly, so apparently it's the Apple USB-C Digital AV Multiport Adapter that's at fault. But it's still a mystery to me why the "faulty" Apple adapters (which apparently your friend's wasn't one of) work with TVs or external displays, but not with projectors. You'd think if it were faulty, it wouldn't work with any of those. I never ended up exchanging my Apple USB-C Digital AV Multiport Adapter and decided to stick with VGA for my current projection needs for other reasons having to do with aspect ratio. I can still use the Apple adapter with my TV or other monitors, so it's not a total loss.
 

joevt

Contributor
Jun 21, 2012
6,840
4,133
Did you solve your problem? I experienced the same.
I have an Apple USB-C Digital AV Multiport Adapter and I used it to connect my new Macbook Air (2021) with two different projectors. In both cases I did not succeed. In contrast, I used the same adapter to connect a couple of displays (Acer and Asus) and all worked perfectly.
Another strange thing: a friend of mine gave me another Apple USB-C Digital AV Multiport Adapter, and the connection with one of the projectors worked fine.
What's the problem??
Were they both the same model?
https://support.apple.com/en-us/HT207806

A2119 is the new one which supports HDMI 2.0. It requires DSC to convert two lanes of HBR3 to do 4K60 8bpc RGB. For 4K60 10bpc HDR, 4:2:2 or 4:2:0 is required which does not require DSC.

Maybe the AGDCDiagnose command from an Intel Mac will tell you if they have the same firmware.
 

usagora

macrumors 601
Original poster
Nov 17, 2017
4,869
4,451
Were they both the same model?
https://support.apple.com/en-us/HT207806

A2119 is the new one which supports HDMI 2.0. It requires DSC to convert two lanes of HBR3 to do 4K60 8bpc RGB. For 4K60 10bpc HDR, 4:2:2 or 4:2:0 is required which does not require DSC.

Maybe the AGDCDiagnose command from an Intel Mac will tell you if they have the same firmware.

I know this was directed at strau, but since I was having the same issue, I wanted to say I'm almost positive mine is the newer version, since I only purchased it in April of this year. It's at work right now, so I can verify that tomorrow.
 

Ramosortega

macrumors newbie
Jan 25, 2023
1
0
I faced this issue and I solved it by changing the projector and screen refresh rate from 60 to 50Hz in System Settings (macos Ventura) or System Preferences (Monterey)
Screenshot 2023-01-25 at 9.08.21 PM.png
 
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