if so, that mean the battery if working fine, so maybe it's just a pairing issue. what i would suggest you to do is try downloading the logitech unifying software https://support.logi.com/hc/en-us/articles/360025297913-logitech-unifying-software, install it on your computer, and follow t...
**Easy Installation and Compatibility** Installing the replacement keycap and hinge is a breeze, thanks to the included easy-to-follow instructions. The keycap and hinge are designed to be compatible with the Logitech K780 Multi Device Wireless Keyboard, Logitech K750 Bluetooth Pairing, and ...