Here's
the complete connection
tracks of Nokia C6 QWERTY keypad keys. There are two EMI-ESD filter
chips and a control IC, some sort of keypad data
signal encoder are used in the keypad connections.
C6 keypad keys connection layout
The C6 Keypad matrix outer and inner core layer connections configuration:
Keypad Inner core layer are all connected to EMI filter 1
Line 1 - Q, W, E, R, T, Y, U, I or ( numeric 1 2 3 4 5 6 7 8)
Line 2 - A, S, D, F, G, H, J, K or ( numeric - + #)
Line 3 - Z, X, C, V, N, M, comma
Line 4 - Fn, Right shift, Sym, Ctrl, @, space, &, ?
Line 5 - O, P, L, Backspace, Period, Enter, Left shift or ( numeric 9 0 )
Line 6 - Up, Down, Left, Right, Select
Keypad Outer core layer are all connected to EMI filter 2
Line 1 - Q, A, Z, Fn, O and Volume up switch button
Line 2 - W, S, X, Right shift, P and Volume down switch button
Line 3 - E, D, C, Symbol, L, Up
Line 4 - R, F, V, Control, Backspace, DownLine 5 - T, G, N, @, Period, Left
Line 6 - Y, H, M, Space, Enter, Right
Line 7 - U, J, comma, &, Left shift
Line 8 - I, K, period, Question mark
If all corresponding keys doesn't work on each group of line connection the problem may lies on on the Keypad EMI filter IC.
If only one or up to three keys won't work or not responding the problem
may only lies on the line connection that possibly being cut or open
paths.
And if tried to replace a new EMI-ESD Filter IC and all the connections
line paths is okay, but the problem still exists the next option is to
rework or by then replace the keypad control IC marked with number 3.
You may check or by then replace those corresponding SMD components such as filter coils, resistors and capacitors.
