In nokia 5250 keypad problem can be due to rust carbon or water damage. in this case keypad parts can be damage or keypad track can be missed from any point. for solving keypad problem in nokia 5250 you can see diagram bellow.Nokia C2-03 MMC Memory Card Problem Solution Ways
In above diagram there are two main paths
these are used for keypad functions and these are controlling keypad
options.these red and blue color lines are describing tracks.
For this post you only can clean the board ic and keypad if there is
some rust or carbon. you can resold these two parts and can replace
these two ic for keypad problem in nokia 5250.
For more detail and new tips and tricks about cellphone service
problem keep visiting this page we will update cellphone service
diagrams timely with new cellphone diagrams. Some related post are also
given bellow you can read them also for more information about cell