HEIDENHAIN iTNC 530 Service Manual page 364

The keys are evaluated via a matrix. Every key is located at a crosspoint of SL (= scan line)
Principle of the key
and RL (= return line). --> See "Key Matrix of the Keyboard Units" on page 22 – 372 or
matrix
See "Key Matrix of the Visual Units" on page 22 – 388.
Is a line (cable, board), the key element of the keyboard or the soft-key row of the screen?
Flowchart
22 – 364
Inspection of the keys
Use the key matrix to find a key that is
selected by the same RL line as the
defective key (and which functions in
the selected operating mode).
Press this key.
Any reaction?
Yes
Use the key matrix to find a key that is
selected by the same SL line as the
defective key (and which functions in
the selected operating mode).
Press this key.
Any reaction?
Yes
The matrix lines (keyboard cable, soft-
key row, keyboard PCB) are in order.
The contact of the key is
probably defective.
No
The line to the matrix is interrupted.
Check the keyboard cable (measure
the cable, try replacement, etc.), the
connectors, the soft-key row or the
keyboard PCB?
No
HEIDENHAIN Service Manual iTNC 530