Dell U3419W connected via USB C keeps scanning for signal when MacBook is sleeping

I use a Dell U3419W with my 2016 MacBook Pro, connected via USB C. When my Mac is closed and sleeping, the monitor keeps looking for a signal. The screen comes on quickly and I hear the sound you hear when you connect your Mac to power.

I found a post in the Dell support forum describing this issue, but Dell doesn't seem to feel any responsibility for their Mac users and sends us to Apple instead. Anyone here has any suggestions?

https://www.dell.com/community/Monitors/U3419W-scanning-for-signal-when-Apple-is-asleep/td-p/7254570

Also, I noticed I can't control the monitor's speaker volume using the volume keys on my Magic Keyboard. Again Dell points at Apple.

https://www.dell.com/community/Monitors/U3419W-MacBook-no-volume-control-with-keyboard/td-p/7316633

MacBook Pro with Touch Bar

Posted on Jul 11, 2019 6:20 AM

Top-ranking reply

slackingtosh

Level 1

8 points

Posted on Feb 28, 2020 3:20 PM

Apparently Apple broke something after 10.14.3. We have been communicating with dell on a similar thread (https://www.dell.com/community/Monitors/U3818DW-USB-Type-C-power-delivery-problem/td-p/7452974/page/2) and their community manager posted that After 10.14.3 Apple broke compatibility with the controller that is used on the U3419W and U3818DW and that Dell cant do anything about it.

"With the release of Apple OS Mojave 10.14.3, Apple introduced a hardware incompatibility issue with our TPS6598E power delivery controller in the U3419W and U3818DW. When connected to the U3419W and U3818DW via the USB Type-C to C cable, if you update the Apple OS to Mojave 10.14.3 or later, you will see the following issues =

* Fully charged Apple MacBook constant "charm" sound due to waking and sleeping

* The monitor will display, "Scanning for Signal"

There will not be a monitor hardware power delivery controller upgrade to correct this hardware incompatibility issue created by Apple. You will need to back down the Apple OS to High Sierra 10.13.6 or earlier.

I received a Dell internal email which stated = There is not workaround to solve the incompatibility with the TPS6598E power delivery controller and the Apple OS 10.14.3. We do not see the issue on Apple OS 10.13.6 and Apple OS 10.12.6."

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Dell U3419W connected via USB C keeps scanning for signal when MacBook is sleeping

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