I believe that you are stating that your model 4775 Braun shaver no longer holds a charge. To repair this you will need to replace the batteries. To replace the batteries, you will need to open the shaver up. First, remove the two round plastic screw covers on the bottom of the shaver then remove the screws that are underneath. The outer casing will then slide off the bottom of the shaver. You will then be able to access the batteries.
You will find batteries for model 4775 at shaveroutlet.com. See link below

http://shaveroutlet.com/braun-battery-nicd-2-batteries-p-454.html