Acer H233H two displays, one works - one doesn't

I have two H233H Acer displays I use at different locations. I use them as a 2nd extended display for my LG Gram laptop. One display works fine every time I turn on my laptop or awaken it from sleep (ser no: ETLHB0D0220XXXXX). The other Acer display (ser no: ETLFS0W0109XXXXX) will not display when restarting or awakening from sleep. I get a "no signal" display on the screen. I have to wait until the laptop is fully awake and then I have to unplug and replug the Acer power cord or unplug and replug the HDMI cable. When I do that, the display interfaces properly and starts to work fine again. I think the nonworking Acer is an older unit. Is there a firmware update needed or any other suggestion on how to get the nonworking display to function properly?

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JackE

One display works fine every time I turn on my laptop or awaken it from sleep

What happens when you disconnect this one and connect the other one in its place using the exact same cable and connection?

billsey

I'll ask the moderators to edit the numbers, you aren't supposed to publish your full SN. Check to see if the laptop has anything set differently between the two monitors, they can have different settings in Windows even though they are identical models.