If the batteries of the FX3960 are completely empty, it can take up to 30 minutes for the LED indications of charging to kick in when the emergency button is on the charger.
This is to prevent the emergency button from being removed from the charger too quickly, causing it to fail during the installation process.
If the LED indication still does not come on after 30 minutes, check whether the charger's adapter is properly plugged into the socket, try another socket if necessary.
If the emergency button still does not work, we recommend contacting us, we will be happy to help.