OK.
Make sure you check the rechargeable NiCd backup battery on the board. It's notorious for leaking and destroying things.
You have to remove the screws holding the top cover on, the screws holding the slots down, and then remove the screws and nuts holding the board interconnects together. Once you do that you can separate the boardstack and check the battery.
I recommend pulling it and the 470 ohm resistor next to it and soldering in a CR2032 socket on the bottom of the board. This way you get rid of the pesky NiCd and you mount the coin cell socket on the bottom so you don't have to disassemble the board stack to replace it when it dies.
RJ