Troubles with USB-C to HDMI adapter on the 2017 iMac

[DuckThom]

I recently bought a USB-C to HDMI 2.0 adapter from Club 3D (the CAC-1504) but when i plug it into my iMac, nothing happens. No screen flickering or anything. It's not a faulty adapter since it's working perfectly fine (4k@60Hz) on my XPS 15 laptop.
In the System Report thingy, it's listed under the USB devices under the USB 3.0 Bus (I would have expected it to be under the 3.1 Bus) with the following info:

DisplayPort ALT mode device:

  Product ID:                   0xc002
  Vendor ID:                    0x06c4  (Bizlink Technology, Inc.)
  Version:                      0.08
  Serial Number:                101
  Speed:                        Up to 12 Mb/sec
  Manufacturer:                 BizLink Technology Inc.
  Location ID:                  0x14700000 / 3
  Current Available (mA):       500
  Current Required (mA):        500
  Extra Operating Current (mA): 0

The thing that seems weird to me is the speed being listed as 12 Mb/s because as far as I know, it should be at least 18 Gb/s as it's capable of 4k@60Hz video output.
Now I'm wondering, could this be fixed in a macOS update or did Apple maybe drop support for these kinds of adapters (USB-C to HDMI). Is this a common problem? I tried Googling but I can barely find anything on the new 2017 devices...

 

[Gav2k]

Have you tried another port? Also are you using a decent hdmi cable??

 

[DuckThom]

Yes, I've tried both ports on the iMac and multiple hdmi cables. All of them are working when I try them on my laptop, none of them work on the iMac.

 

[EugW]

Apple changed something with the 2017 iMac, MacBook, and MacBook Pro. A lot of HDMI adapters that work with the 2016 do not work with the 2017.

Can you use DisplayPort? Some of the DisplayPort adapters still work.

 

[DuckThom]

I see, sounds to me like it could be a driver issue rather than a deliberate action to break support for those adapters. (Then again, it wouldn't be the first time Apple dropped support for a widely-used port *cough*headphone jack*cough* ). I could try a DP one but I only have 1 DP port on my monitor and it's already in use, and, I dont have any DP adapters at hand either so I'd have to buy one first.
I also sent an email to Club 3D and got a reply that it "looks to be heavily related to the OS version". I've replied to that email with my OS version (10.12.5) and am now waiting for a reply again.

 

[DuckThom]

I just received a reply from Club 3D. They asked me to test macOS 10.13 beta2, unfortunately, I don't have a developer account so I cannot download that version but maybe someone else here can download it and test a USB-C to HDMI adapter?

 

[EugW]

I just received a reply from Club 3D. They asked me to test macOS 10.13 beta2, unfortunately, I don't have a developer account so I cannot download that version but maybe someone else here can download it and test a USB-C to HDMI adapter?

That won’t be very helpful unless it’s the same exact adapter.

 

[DuckThom]

That depends, if it's a general problem (which is what it looks like to me since you said other USB-C to HDMI adapters are having the same issues), it might also work for those other adapters, not just the Club 3D one. Ofcourse, you don't have to test it, but it might be worth a shot for someone with an adapter that's currently not working and is willing to test it.

 

[EugW]

That depends, if it's a general problem (which is what it looks like to me since you said other USB-C to HDMI adapters are having the same issues), it might also work for those other adapters, not just the Club 3D one. Ofcourse, you don't have to test it, but it might be worth a shot for someone with an adapter that's currently not working and is willing to test it.

It’s not really a general problem. I think someone here mentioned the Apple Digital AV cable does work.

The problem is that there are multiple different chipsets out there. For example, some DisplayPort adapters/cables work, and some don’t.

My previous USB 3.0 SATA dock doesn’t work with the 2017 iMac either. Works fine on my old iMac. So I went out and bought a new USB 3.0 SATA dock and the new one works perfectly with the 2017 iMac.

 

[DuckThom]

I have just installed the public beta of High Sierra on a separate partition and now the adapter is working!
After rebooting back to Sierra, the adapter also briefly works (the second display is now also listed in the System Report) but it quickly goes back to "No Signal", so it's definately a problem with 10.12.5.
[doublepost=1498843580][/doublepost]Actually, strangely enough, I just unplugged the adapter and plugged it back in and now the display IS working in 10.12.5, strange issue... But apparently installing and booting the public beta, rebooting back to Sierra, unplugging the adapter and then replugging seems to have worked (for now).

 

[trigf]

It’s not really a general problem. I think someone here mentioned the Apple Digital AV cable does work.

OP is looking for 4K at 60Hz. Apple's own adapter doesn't do that.

https://www.apple.com/shop/product/MJ1K2AM/A/usb-c-digital-av-multiport-adapter

I am in the same predicament as OP, and need to find an adapter that can output 4k at 60Hz from my 2017 iMac. I don't have time to slog through dev or public betas of unreleased operating systems in hopes of finding a solution, while breaking a program I need to make a living.

Tons of third party manufacturers are reporting that their perfectly functioning USB-C to HDMI adapters work on everything except the 2017 Macs (both desktop and laptop).
[doublepost=1499307850][/doublepost]

I have just installed the public beta of High Sierra on a separate partition and now the adapter is working!
After rebooting back to Sierra, the adapter also briefly works (the second display is now also listed in the System Report) but it quickly goes back to "No Signal", so it's definately a problem with 10.12.5.
[doublepost=1498843580][/doublepost]Actually, strangely enough, I just unplugged the adapter and plugged it back in and now the display IS working in 10.12.5, strange issue... But apparently installing and booting the public beta, rebooting back to Sierra, unplugging the adapter and then replugging seems to have worked (for now).

That makes absolutely no sense as to why it suddenly works. Glad it's working for you, but I can't risk a beta OS to test a display adapter. I need my computer to make a living.

 

[PJivan]

I have just installed the public beta of High Sierra on a separate partition and now the adapter is working!
After rebooting back to Sierra, the adapter also briefly works (the second display is now also listed in the System Report) but it quickly goes back to "No Signal", so it's definately a problem with 10.12.5.
[doublepost=1498843580][/doublepost]Actually, strangely enough, I just unplugged the adapter and plugged it back in and now the display IS working in 10.12.5, strange issue... But apparently installing and booting the public beta, rebooting back to Sierra, unplugging the adapter and then replugging seems to have worked (for now).

Does it work in bootcamp?

 

[DuckThom]

Does it work in bootcamp?

I cannot test that, I don't use bootcamp.

 

[Rychiar]

I just got my 2017 iMac last week and was really annoyed to find out they removed the optical audio ability from the headphone jack. I heard the USB C ports doubled as HDMI however, and decided to buy a whole new fancy stereo to replace my aging Logitech z-680. I got an onkyo receiver and was so excited to try it out last night. The mac sees it fine and it's listed under all the sound preferences using a well reviewed usbc to hdmi cable I got on amazon. The receiver however only very intermittently sees the mac. Like if I'm lucky I can get music or movie audio that plays for a couple seconds every few seconds or so. It's all broken up and the hdmi and Dolby lights keep turning on and off on the receiver screen as it's playing... so annoying. If think after spending all this money I'd have a stereo solution that works but notsomuch. AirPlay works great but I mainly spent this money to push true Dolby surround from VLC.

 

[EugW]

I just got my 2017 iMac last week and was really annoyed to find out they removed the optical audio ability from the headphone jack. I heard the USB C ports doubled as HDMI however, and decided to buy a whole new fancy stereo to replace my aging Logitech z-680. I got an onkyo receiver and was so excited to try it out last night. The mac sees it fine and it's listed under all the sound preferences using a well reviewed usbc to hdmi cable I got on amazon. The receiver however only very intermittently sees the mac. Like if I'm lucky I can get music or movie audio that plays for a couple seconds every few seconds or so. It's all broken up and the hdmi and Dolby lights keep turning on and off on the receiver screen as it's playing... so annoying. If think after spending all this money I'd have a stereo solution that works but notsomuch. AirPlay works great but I mainly spent this money to push true Dolby surround from VLC.

Which USBC to HDMI cable? A lot of them that are well reviewed don't work properly with the 2017, even if they worked properly with 2015 and 2016 Macs.

Did you check to see if any of the positive reviews came from 2017 Mac owners?

 

[Shirly Chou]

i test one cable and adapter, it works perfectly to my 2017 macbook Pro, please try one
https://www.amazon.com/gp/product/B075YC317R
https://www.amazon.com/dp/B075YHD5HT
one is adapter, the other is cord