No signal detected by projector

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Level 1

16 points

No signal detected by projector

I have a problem that has been happening to several of my teachers after getting them new MacBook Pros that have the thunderbolt 3 (usb-c) ports. When they connect to the projectors in their classrooms their laptop syncs resolution and shows the proper projector in Displays, but the projectors say no signal. There has been no consistent solution to get it project. The problem is occurring on multiple projectors (some older Mitsubishi, some ViewSonic, some brand new Casio) and several different teachers with MacBook Pro laptops ranging from brand new to 1-year old. The teachers with the older MacBook Pros that have the HDMI port on the side do not have this issue.

Things we've tried:

Different brands/styles of USB-C to HDMI adapters and even a cable that directly goes USB-C to HDMI without the need for a separate adapter.
Unplug/re-plug the cables.
Bypass the wall plate and use a cable plugged directly into the projector.
Override the default settings for the connected display and manually set resolution

Any of these solutions (except manually setting resolution) work...sometimes, but none of them work consistently to fix the issue. My guess is the signal is simply not strong enough, but that is just a guess.

Any thoughts and ideas would be appreciated.

MacBook Pro with Retina display, macOS High Sierra (10.13.6)

Posted on Sep 6, 2018 7:59 AM

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Answer 1

Sep 6, 2018 8:11 AM in response to m5yr3k

I am sure you checked for updated drivers to work with your projectors, e.g. Epson. Not until I had a particular driver was I able to establish a connection with a pesky projector.

https://www.epsondriverupdate.com/epson/epson-projector-driver-for-mac/

Others will have better suggestions, but since you are using different projectors and quite possibly different configurations even of the same OS there may not be 'one' solution.

You may end up having to have a set of custom instructions per device set up.

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Answer 2

etresoft

Level 8

46,464 points

Sep 6, 2018 8:20 AM in response to m5yr3k

What brands have you tried? Problems like this are almost always caused by dongles. Years ago, an automatic response would be to use only Apple dongles. That isn't true anymore. I have gotten very good results from dongles that are a third the cost of Apple dongles, which have horrible reviews.

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Answer 3

Sep 6, 2018 8:52 AM in response to m5yr3k

"Stacking" of adapters is seldom successful. You must go from the computer port to the display input port in ONE adapter.

The Apple ThunderBolt-3 to ThunderBolt-2 adapter does NOT provide any directly usable display signals at all. It disclaims the ability to produce Mini DisplayPort.

HDMI at higher than 1920 wide requires an ACTIVE adapter.

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Answer 4

m5yr3k Author

Level 1

16 points

Sep 6, 2018 10:39 AM in response to etresoft

I've tried Cable Creation and Amazon Basic (I think), and a USB-C to HDMI cable (i.e. no other adapter needed). The Apple dongle is so overpriced I really want to avoid it if possible. The cost adds up when I need to provide connectivity to 20 different rooms.

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Answer 5

m5yr3k Author

Level 1

16 points

Sep 6, 2018 10:43 AM in response to Grant Bennet-Alder

There is no stacking of adapters. Only one USB-C to HDMI dongle. I'm curious about your last statement and will need to investigate further. I'm not sure what resolution is being used in each scenario because the display preferences simply state Best For #######, where ####### is the projector model. I'm not familiar with what an ACTIVE adapter is, but I know at least some of the adapters used say they are good for 4K resolution. I would think that should be fine for just mirroring the teachers' displays.

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Answer 6

Sep 6, 2018 11:46 AM in response to m5yr3k

Mirroring is surprisingly complex. Apple decided long ago that mirroring would be pixel-perfect, and the displays would be in sync. So the resolution chosen when you say mirroring is a compromise between the best resolutions of the built-in display and the projector. Sometimes it is not a good choice, and one or the other drops out.

HDMI higher than HD: 1920 by 1080p requires special equipment to get to those numbers, and often drops back to 45Hz or even 30Hz in the process. so if it defaults to higher, you may be more likely to actually get a picture if you can set it to HD or lower.

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Answer 7

etresoft

Level 8

46,464 points

Sep 6, 2018 11:06 AM in response to m5yr3k

I've never heard of those. Amazon has a very poor reputation as a source of cables. When in doubt, you can always go to OWC (https://eshop.macsales.com/search/?q=usb+hdmi).

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No signal detected by projector

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