How long have you had the shaver? If it has been a couple of years, then it sounds like the batteries are exhausted.
The batteries can be replaced, although it's not as easy as changing them out of a flashlight. There is a way to disassemble the shaver and change the batteries. They are soldered in place at two basic points. If you obtain replacement batteries (on eBay you can get them for about $12 a piece), you can perform the replacement yourself:
Opening a Braun 7000 Series Shaver
1) Find a thin metal object with no sharp edges (such as a nail file). Use your thumb and pull on the bottom end cord socket part, enough to cause a gap between it and the back shell. Insert the metal object into the gap in the center of the part. THEN pry it off. If you use a regular screw driver, you will likely cause gouges in the plastic. And the best leverage is in the center.
2) The silver side parts are held on by two tabs at the top. With the bottom piece gone, the side parts swing off easily. Don't worry about keeping track of which sides the silver trim pieces go on, as they're designed to fit on only one side (you'll see the cutout for the shaver head stem is off to one side).
3) The case is held together by 4 small torq screws. Use a torq screwdriver--do not attempt to do this with anything else. Be careful to turn the screws slowly, so you don't strip them.
4) With the screws removed, the two halves of the shaver will come apart. The remaining parts can be extracted without any special tools. Keep note of how they are removed, as assembly will be the reversal of removal.
5) Note that if you are replacing the batteries (there are two of them), you will need a soldering iron to detach them from the circuit board, unless you're replacing the whole part.
6) Reassembly is pretty much what you expect--the reverse of disassembly. However, the bottom cord socket part is tricky to get put into place. Pushing straight down on this part will not get it to go in, nor any other obvious way. It's best to get the prongs inserted on one side, then while pushing in on the prongs of the opposite side, apply pressure on the top side surfaces. The part should snap right back into place.
Mine will not charge and even the AC power cord directly into the unit will not make it work.....it is dead as a door nail....
The red light flashed after several months. When I put the 7526 in the base and pushed the charge button, the green light does not light. When the green light on the base goes off, I turn on the shaver and the red light flashes. It sound like it has been charged but the red light keeps flashing.
Usually answered in minutes!