You should first check to make sure that the keys around that area work. The second thing to check is if the plastic rivets around that area are broken off. It'd ruin your day if you have a back plate that's bent or a barrel plate that's cracked.
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I had a 6+ inch (4.21 terrawatts in metric) crack in a Model M 122 bottom case and one of the screw mounts was broken off. I asked here for the best stuff to repair it with. The answer was
JB Weld original (also on Amazon and probably in most hardware stores). This works EXTREMELY well, but note that it dries grey, so you'd want to do the repair from inside the case. Use as little as possible. Follow the directions closely.
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You can get a brand new case for $30 US on
Unicomp's website. However, you should contact them first to make sure your keyboard's core fits.
You can also get some caps ("buttons") to replace your missing ones.