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‎12-23-2021 10:20 PM

HP Recommended
Product: U28 4K monitor

I can't get my U28 USB C port to deliver power to a USB powered sound-bar after U28 powers up.  I have to unplug and replug the USB C cable while a sound signal is present for it to work! ... More strangely, the sound-bar can't get enough power to drive the sound when connected to any of the U28's USB B ports.  But when I connect a Pantech modem charging port to the U28 USB B port, the midem gets all the amps it wants to stay charged, and to put out secondary power for the sound-bar!  Why are U28 ports so weird?

Category:
2 REPLIES 2

‎12-24-2021 01:52 PM

HP Recommended

@AnsaMatt 

 

What is the wattage rating required for your sound bar ? Does it have USB-C port ?

 

The USB-A ports only have standard wattage rating. May be you can use USB-C port because its power delivery is up to 65W

 

Regards.

BH
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‎12-24-2021 04:57 PM

HP Recommended

Thank you, Banhien.  I *am* using the USB C port to power up the sound-bar in one of the scenarios I have described.  In this scenario, starting from a monitor shutdown I have to start the sound signal coming from the monitor's 3.5mm audio out port (play a video for example on HDMI port), then unplug the sound-bar's USB power cable from the monitor's USB C port, and plug it in again in order to hear the sound.  Even though the sound bar light is "on" when plugged into USB C port, it produces no sound if the sound signal starts after its powered up from USB C!  It was a similar situation with a chargeable Bose speaker that needs 1 amp 5 volt charge source.  The U28's USB C port seems to have a mind of its own and send to provide power under certain demand circumstances.  It's not a plug and play port and the firmware doesn't allow it to be reconfigured.  It is meant to be plugged into a laptop, and won't offer rated power without an intelligent demand signal even though the U28 is set up for Performance.  BTW, all of this is possible if USB C is in 3.0 mode.  In 2.0 mode it provided zero power.  At least the older USB ports are dumb enough to be functional in more predictable ways 🙂 ... My solution: don't shut down the monitor.  Let it only sleep.

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