Stap 14 vertalen
Now is an excellent time to clean the fan and the cooling vanes through which it blows air. If necessary you can use a pin to dislodge dust stuck to the heat exchanger vanes, then a vacuum cleaner crevice tool to suck it out.
The backup battery is just to the left of the RAM sockets on a pair of flying leads. Remove the modem module (just above it in the photo - retained by a single screw) in order to disconnect it.