How to Trace and Map Keypads Layout on Mobile Phone Printed Circuit Board (PCB)

There are few methods in tracing and mapping the keypad layout on a mobile phones keypads on printed circuit board. One of this quick and very easy method is by using an schematic diagram, if that certain mobile phones have available unto it. Schematic diagram is very useful guide in every aspects of hardware troubleshooting.

Now assuming that you already have knowledge how to use and read it, follow this simple steps below.
 Browse to bottom of the pages where yo can locate and find like the picture below., it is the keypad  circuit section. In that schematic layout you will notice that each corresponding key characters is being group into lines. This group of keypad switch lines  is being marked with rows and columns.

  trace each and every lines where those keypads switch symbols is being connected, once you been manage to trace it. configure and trace it on the printed circuit board by using an analog or digital multimeter, just set it the resistance value X1 and attach both probes to corresponding keypads groups in  every rows and column

Practice this kind of method with an aide of schematic diagram, in this way if you're skills grows further, you can then trace any other mobile phones without any schematic diagram available at first hand.

Posted in: Mobile Phone Repair basics