3rd party display port adaptor no longer works properly

[elf69]

I been running High Sierra since public release and I like it.

On Sierra I was using a 3rd part adaptor. This adaptor has VGA, DVI and HDMI in one neat adaptor.
Only one output may be used at any given time.

All worked fine, except VGA which only did 800x600 or 1024x768. but if use DVI to VGA adaptor on the DVI port then many more options available.

Anyway not use the adaptor for a long time as not needed.

yesterday tried it with HDMI and the screen showed image briefly then screen just flicks between black and just noise 3-4 times then screen says no input and Mac no longer see the screen.

Now connect a DVI screen and everything is fine.

tried adaptor on a brand new 2017 MacBook Air I'm setting up for a friend, same result.
Tried 2 more screens again same.

Tried new adaptor, again same 3rd party manufacturer, same result.

is something different in HS for HDMI output?
DVI to HDMI adaptor plugged into the 3rd party adaptor fixed the issue.
But not like using adaptors on adaptors if can be helped.

 

[Commentist]

Odd. It could be a driver issue - you might need to download a new one from the manufacturer. HS seems to have
made some changes that give better display performance. There were apparently some problems with DisplayLink
devices under the HS beta. I'm not sure whether I can post a link on here, but Plugable has a report, and there is a link
to the DisplayLink driver page if it's one of theirs.

"Note: macOS 10.13.4 Beta 1 appears to have several display-related issues, and is not recommended. There are reports of problems using DisplayLink devices, USB-C “Alternate Mode” outputs, and Thunderbolt 3-attached displays. DisplayLink is tracking this issue"

I personally tend to use separate adaptors rather than combined ones (displayport/TB to either VGA or DVI or HDMI). I've had some fail on me over the years. It's not always obvious that the hardware is faulty, but if you've tried two different adaptors and machines then it is less likely.

 

[elf69]

my own fault really for using stupid cheap units

https://www.ebay.co.uk/itm/Mini-Dis...869363?hash=item3399cfdfb3:g:kuwAAOSwu4BVucK2

this is what I was using on Sierra.

with this adaptor on High Sierra, VGA and HDMI do NOT work.
DVI will not work with a DVI to VGA or DVI to HDMI.
It will only work with DVI equipment which is little odd.