If you are simply trying to improve the performance of your Toughbook CF-19, and have determined that you need more memory, I recommend upgrading the above-deck RAM module that can be easily accessed via a panel on the underside of your computer. The internal RAM module that comes standard with the CF-19 is already the most powerful module the laptop will accept.
If your computer can't perform basic functions, like booting up, the internal memory module may have burned out (it's not common, but occassionally happens). When a computer dies, people often assume they need to buy a pricey new system board. Try swapping out the RAM first. You might save a few hundred dollars.
It's a pretty straight-forward procedure. The only tool you'll need is a small Phillips-head screwdriver.
Step one: power down completely.
You never want any power running through your Toughbook when handling its internal components, and RAM modules are particularly sensitive. Shut your Toughbook down completely, disconnect the AC adapter, remove the battery, and get static free before starting.
Step two: remove the bottom cover of the laptop.
Lay your CF-19 upside-down. There are 13 screws holding the bottom cover, or base bezel, in place.
Simply remove the screws, open the port covers, and lift the bottom off.
Step three: access the memory.
After you've removed the bottom bezel, you'll find the RAM module in the front, right-hand corner. It will be underneath the battery board ribbon cable (part #: DFHM0407) and plastic memory bracket (part #: DFHR6284ZA). If there are two RAM modules in your CF-19, we will be dealing with the bottom one. You may, however, find that you need to remove the top module just to get it out of the way.
Remove the three screws circled below, then carefully unhook the ribbon cable and move it aside.
Once the ribbon is out of the way, we'll be able to access one last screw that we need to remove.
Step four: replace the RAM module.
After taking out the screw, carefully remove the black plastic bracket and set it aside. We now have access to the RAM module. Simply push the clips aside to pop it out.
Insert your replacement module, then put everything back together the same way we took it apart.