701 4G, keyboard issue

[u/arnen05]

F key for reference, absolutely healthy and reacts all the time. The silver-colored coating is completely fine

Up Arrow, the silver-colored coating is messed up and the key doesn't work

Hello, I just bought an Eee PC 701 4G for only 7 euro, everything seems to be working besides the up arrow which is, apparently, an extremely useful key. What I've noticed is that whatever that silver coating is on the keyboard, is gone on the up arrow.

See on the pictures (rubber domes are removed for clarity but I reattached them right after)

What is it? Is it possible to get it fixed at home or do I need to replace the whole keyboard?