Dell XPS, Keyboard Glitching

[EdwardGeo]

MODEL NAME AZ10
PCB NO :LA-F211P

After bumped battery removal the keyboard doesn’t work properly. When pressing any key, it will react 5-7 times after 5-15 seconds.

The keyboard connected to KBC board. The cables are fine, all signals are checked

[EdwardGeo]

Re: Dell XPS, Keyboard Glitching

MODEL NAME AZ10
PCB NO :LA-F211P

After bumped battery removal the keyboard doesn't work properly. When pressing any key, it will react 5-7 times after 5-15 seconds.

The keyboard connected to KBC board. The cables are fine, all signals are checked

Dell XPS 15-9575 2-in-1
Schematic: https://www.badcaps.net/forum/showthread.php?t=106363


The problem comes from kbc board. That board is connected to EC through I2C interface. Will analyse data packages. My theory is based on EC as master sends command to read KBC ECE1117 buffer, but the buffer is empty or stuck with keycode.

In different laptops I have saw the internal iospace ram buffer with keycode, and keycode always remain the last status. So if ECE1117 has a failure, then it will not fill a buffer, it will not reset a buffer

[mon2]

Re: Dell XPS, Keyboard Glitching

Confirm the I2C pull ups are still present on this leg of the circuit.

Review the 32.768khz clock source on the KBC.

[EdwardGeo]

Re: Dell XPS, Keyboard Glitching

Confirm the I2C pull ups are still present on this leg of the circuit.

Review the 32.768khz clock source on the KBC.

Thanks!

I2C data and clock present. Have captured traffic, will analyze for difference between keypress “1” and key “2”

KBC_Det is gnd connected
KBC_Int is pull up 3.3v, but goes to 0v when key pressed

[mon2]

Re: Dell XPS, Keyboard Glitching

Try a bios update

https://www.dell.com/support/kbdoc/e...aracter-repeat

[EdwardGeo]

Re: Dell XPS, Keyboard Glitching

Try a bios update

https://www.dell.com/support/kbdoc/e...aracter-repeat

Incredible! It works!

Thank you for your help!