How to connect a ground wire to the KB-702GM power input connector (U-BOX)
This should only be done by a competent engineer.
Ensure the power adapter is un-plugged from the U-Box
Open the unit and remove the front cover. Also, unscrew the two screws from the power supply connector as shown below:
Remove the heat shrink cover and solder a wire to the ground pin as shown below with Green cable:
Insert a new heat shrink cover and attach the ground cable to the connector point where the front cover connects to the base.
Now the KB-702GM power connector has a ground point.