Hi ! First of all i'm French so if i do some mistakes in the text please tell me. Second i'm just a technician in engineer school, i do my best to learn a lot but i'm far from an engineer.

Recently my friend's Keyboard died, he don't know why, suddently keys stopped to work. It's a pretty expensive keyboard "Asus ROG GK2000" and the fact is some functions still works like volume control. I opened it and tried to catch the problem but i'm totally lost. USB continue to send some data, i think it's normal the computer try to talk, but everything looks pretty good in it and i'm to poor in knowledge to fix it alone so i'm trying to find someone to help me and explain to me how to find and resolve the problem.

Thanks a lot if you can help me, if it's needed i could post some pics.

 

Have tried the keyboard on another computer? Sometimes these fancy flashing keyboards have driver issues with OS updates.

 

The first places I'd check..
Did the cord get pinched (breaking one of the small usb or lower wires inside)
Or, is the connector not making contact?

 

All wires are ok, the main usb cable is very strong nothing about it..
By the way the keyboard receive data from the PC, if i do a caps lock with an other keyboard the led of Keylock is On on the broken one, same for numpad, and he send data cause the volume control works fine

 

Are you somehow turning on caps lock from the PC? Or are you saying the caps lock button on the keyboard works because pressing caps lock turns on the LED on the keyboard?

when the keyboard is plugged into the PC, do you get a "caps lock" warning when the PC requests you enter your password to unlock the OS.

 

If i press caps lock with an other keyboard the broken one light the Caps Key so he receive the data of the Caps ON, same for numpad

 

So, no keys work to enter data to the PC screen.

PC can send data (cap lock status when clicked on another connected keyboard).

So, the keyboard is getting some USB power as well (to light up the cap lock or num lock LEDs).

It is unlikely that all keyboard switches would fail at the same time.

I think the fault is likely in the power to the pull-up (or grounding to the pull-down) resistors that would help create a digital transition (falling edge or rising edge) when a key is pressed.

After you measure at one or more switches that you get a digital transition and prove that is not a problem, you can look at the USB signals by adding a patch cord between PC and keyboard so you can connect to keyboard (unless you can see some nice attachment points for the scope inside of the keyboard, then just use those points - D+, D- and ground for both scope probes. Here is a video...

 

Ok so i try some things and i'm pretty lost...

First of all, i used my scope to look at D- and D+ but my scope isn't good as the video you sent and i can't figure out how to get a nice view of the signal but anyways it seems to don't send any data


After that i tried to just look at the signals coming to keys and i've been really confused cause some keys got a 3.3V in but some keys doesn't and it's not like an array just random key doesn't get signal in..

I really don't know what to do now and i think i didn't get enough knowledge to find and fix the problem.. That's break my heart but it's a fact..