The solution may help repair and fix nokia 5130 keypad malfunction and button switches failure. You may check, trace particular keys which are not able to function by using the repair guide below. Each group of colors indicates that they are connected with each other. So just locate where that particular non working key being connected and mend it found cut or open.
Nokia 5130 xpressmusic keypad keys malfunction full tracing solution
The Power ON/OFF key is isolated and not connected to other group of key connection for it only holds for switching or powering up the device. There is an open spots near the keypad filter IC that the power ON and OFF key can be connected when the power key fails or or if the line is cut or open.
Nokia 5130 ON-OFF power key jumper ways
And here's the internal connection of the keypad filter IC, you may check and apply a temporary jumper on this components to ensure that the inner line paths from the application processor is not being damaged.
Nokia 5130 keypad filter IC jumper ways