Wednesday, August 31, 2011

How to fix keys on laptop keypad not working even keypad already replaced.

If you replaced the keyboard and the same exact keys are still not working then you most likely have a system board issue.
But check basic things and make sure before turning to any chip level operation that did you insert the cable properly and is your zip connector or header of keypad is good or broken from anywhere?

Some of my known people who connected with the laptop computer hardware repairing filed but they don't done any chip level work on laptop so they use to send me the faulty laptop for repair in which they feel a chip level issue they do only diagnose and fix only software and common hardware level problem like installation of software, OS and part replacing work replace hard drive, ODD, LCD, Keypad, Touch-pad, Hinge and main board but replacing main board is too much costly.
Some time problem can't get fix after just replacing the part that they think is a faulty spare because they do repair on the basic diagnostic way if keypad not working ( problem can be some keys not working or functioning properly, keypad died not detected at all ) after checked some basic thing like OS issue driver and finally replaces the keypad as usual we all have to do.
But if problem couldn't get fix then its means problem is not a normal issue that will need a chip level operation so as usual they forward me this case. When they come to me most likely they said ''I have replaced the keyboard on this laptop 2, 3, 5 times but sill keypad not working.” These same letters stop working after a while. Replacing the keyboard worked before'' also most of the time same thing happened with mouse touch-pad.
Before I going to tell how can easily repairer this kind of case..I just want to remained you a basic block diagram of laptop motherboard.




As this diagram keypad and touch pad PS/2 controls are controlled by EC chip and if EC chip not present than I/O chip controls the PS/2 control.




Every laptop notebook manufacture uses a different type keypad model and their header for their different laptops models. And there header size and their pin datasheet may not be same. so before wasting your time to get datasheet and any other solution to fix the problem to searching on Google just re-soled the I/O chip and pull up resistor pack capacitor pack or simple SMD resistor which have connected with keypad connector and direct with I/O chip because today laptop manufactures use the I/O chip which have in built EC controller.
You can use hot air blower or a micro iron for re-soldering process… mostly pull up resistor and capacitors has solder nearby the keypad connector or header.

Pay little care if you have not familiar with SMD components.
If after re-soldering can fix you problem then you must have to change the EC or I/O chip :(
have a good luck :)