This solution covers for Nokia 6710 navigator keypad problems, if one of the following keys like 1,2,3,4,5,6,7,8,9,0,#,* and space doesn't work or not responding.
The solution below shows the connection line paths of the Nokia 6710 keypad keys. You may trace it connection accordingly by the given solution below.
Nokia 6710 slide keypad solution with filter IC jumper ways
There are two ESD/EMI filter used in the numeric keys, you may replace these filter chips if many of the keys doesn't work or each particular connection line paths is not open or cut.