HP Elitebook 2740p Wistron Norn 3.0 mainboard Keyboard Partial Working Help !!!

[sparrow2719]

Hi, my HP Elitebook 2740p with motherboard code: Wistron Norn 3.0 has a problem with partial keyboard working, there are 4 keys that are not working when pressed.

I've already changed the EC chip SMSC KBC1098 and it still the same. Change another keyboard is also just the same.

I traced the 30 pins keyboard connector down to the EC pins and all was good.

Confused here...is any solutions for this ?

I also noticed there is a one small Capacitor array missing near the keyboard connector, it is labeled 220. Is there any influence of this missing cap array ? As it is just a pack of capacitor connected to ground from the keyboard line.

Any suggestions or help please ?

[SMDFlea]

Re: HP Elitebook 2740p Wistron Norn 3.0 mainboard Keyboard Partial Working Help !!!

Have a look at the schematic . https://drive.google.com/file/d/0B6I...NSMEViSVU/view

[sparrow2719]

Re: HP Elitebook 2740p Wistron Norn 3.0 mainboard Keyboard Partial Working Help !!!

Already had a schematic, but cannot find the clue why there are not working 4 keys on the keyboard while all the tracks from keyboard connector to the EC are good.