I've had my 5A crossovers out and have modified them slightly. (Only a Philips screwdriver is necessary to remove them from the speakers.) As you can see, they are complicated and quite crowded. Here's a pic of an original.
The batteries are soldered and strapped onto the board, so replacing them requires some soldering and mechanical skills. I strongly suggest you remove the crossovers and measure the total voltage; the batteries are wired in series, so 'good' would be somewhere in the mid to high 20s.
