AT YOUR OWN RISK, PLEASE. Li-ion battery inside.
My 2.5 year-old UniFi Cloud Key Gen2 plus was found dead in the server rack.
No power at all from the PoE.
At a glance, the power seemed okay from the USB-C jack. But, the box was showing "BAD USB-C POWER". (Please also read the botton for a lucky solution.)
And this... Oh, dear!
Unpacking the box
Be careful not to break the display when removing it.
Prepare for a burst.
Go to a safe place or use a metal bucket when sliding the enclosure or removing the battery.
My Li-ion battery wasn't swollen, luckily. Graceful shutdown doesn't work now.
The components are all small. There was nothing I could do.
Cloud Key Gen2 plus requires USB-C power source capable of Quick Charge 2.0 or higher. After buying a QC 3.0-capable adapter, my box has come back to normal operation.
The "time bomb" is still in the box, though.
Hope your Cloud Key will last long.