K750 Keypad not working

[ama95]

You can try cleaning it.

[oleq83]

What should I clean? I've tried with another keypad and the same happened there, so there can't be dirt inside the keypad, and the phone looks clean inside. I've also tried flashing it.

I think that it must be a hardware problem, but it's just so weird that it's only the three buttons and the right, down that doesn't work.

Anyone know if there is like a chip or something that "controls the keypad", that can be replaced/soldered?