Clean the contacts of your cordless phone charger with a pencil eraser to remove dirt and debris if your phone is not charging. Plug the phone back in after cleaning to see if it charges. Leave your phone off the charger until the battery dies once a month to prevent problems with the battery having a false charge.
Check the battery using a multimeter to see if it is holding a charge. Remove the battery from the phone and hold the multimeter to the connection on the battery that goes to the phone. Set the multimeter to the DCV scale. If the reading is 10 percent below the battery rating, the battery is dead.
Check the phone line with a phone known to be working if you are not receiving a dial tone on the cordless phone or it isn't ringing. A working line indicates the cordless phone is broken.
Replace the phone antenna if it is not receiving a good signal or there is a drop in signal performance. Remove the back of the phone by removing the screws or undoing the clips. Remove the antenna with a screwdriver by removing the screw holding it in place on the circuit board. Replace with the new antenna.