# How complicated are USB-C to HDMI adapters inside? Intermittent display detect fail on wake

**URL:** <https://boards.straightdope.com/t/how-complicated-are-usb-c-to-hdmi-adapters-inside-intermittent-display-detect-fail-on-wake/800598>\
**Category:** Factual Questions\
**Created:** [November 3, 2017, 2:53pm UTC](https://boards.straightdope.com/t/how-complicated-are-usb-c-to-hdmi-adapters-inside-intermittent-display-detect-fail-on-wake/800598 "2017-11-03T14:53:31Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\
**Post date:** [November 3, 2017, 2:53pm UTC](https://boards.straightdope.com/t/how-complicated-are-usb-c-to-hdmi-adapters-inside-intermittent-display-detect-fail-on-wake/800598/1 "2017-11-03T14:53:31Z")

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What is actually going on inside these display adapters? My new iMac and extra displays occasionally fail to detect on waking, leaving an extra display black and in power-save mode. Could it be an adapter issue?

I’m curious whether there is much active electronic activity, power consumed, and so forth inside these things. For example, is there a constantly growing range of modes that some don’t support?

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**Author:** ![HurricaneDitka](https://avatars.discourse-cdn.com/v4/letter/h/96bed5/32.png) [@HurricaneDitka](https://boards.straightdope.com/u/HurricaneDitka)\
**Post date:** [November 3, 2017, 2:55pm UTC](https://boards.straightdope.com/t/how-complicated-are-usb-c-to-hdmi-adapters-inside-intermittent-display-detect-fail-on-wake/800598/2 "2017-11-03T14:55:34Z")

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> [@Napier](#):
>
> What is actually going on inside these display adapters? My new iMac and extra displays occasionally fail to detect on waking, leaving an extra display black and in power-save mode. Could it be an adapter issue?
> 
> I’m curious whether there is much active electronic activity, power consumed, and so forth inside these things. For example, is there a constantly growing range of modes that some don’t support?

I have the same problem, and the short answer is yes to both (could be an adapter issue, and there is a growing range of modes that some don’t support). Just switching to a new HDMI cable solved my problem in one case.