I realize this isn't really an embedded electronics question - but I'm really looking to learn about the underlying electronics in a laptop keyboard. Please advise if I should post somewhere else. Thanks!
Hi there,
I've been having some issues with a Dell 7359 keyboard and have some assumptions I'd like to check with people who know more about electronics than me. My issue is that that some of my keyboard keys on right side of keyboard are not working. These include the right key, down key, delete key, right square bracket ], and I believe the insert key. Here is a picture of my keyboard.
A couple really interesting things I've noticed: A couple keys will work sporadically. These include the down key, and the right bracket.
Even more interesting: at one point the square bracket key ] wouldn't work, but if I hold shift, this key works, meaning that I can make the } key work easily but not the ] key.
My question: Can anyone give me a quick understanding of why a base key might not work but it's SHIFT+key combination might work? Does the shift key route the key press signal to a completely different location on the circuit board? Like some sort of analog multiplexing?
I am really wondering if my physical keyboard is perhaps in working order, but the so called "keyboard daughter board" and associated cables may have some damage or loose connections. Here is a picture of a Dell Daughter Board. From what I can see in videos, the two small connectors power the keyboard backlights. One big connector goes to the physical keyboard, the other goes to the motherboard.
Another Question: Does anyone have any intuition with these problems and a recommendation? If you have any guides on how to troubleshoot connections in these connectors and cables, I would be very grateful. I am thinking of doing continuity checks of the keyboard hardware, ribbon cables, and this keyboard daughter board to try and isolate the problem. Below is a picture of a Dell ribbon cable I may buy to try and fix issues. Although I barely now how to get confident readings out of the cable. I guess maybe I should try it first when it's docked into the connector to make things easier?
Dell kindly made a decent service manual for this laptop, which supposedly shows device specific steps to remove all components. However they don't seem to stock OEM replacement hardware on their website, so I'm stuck looking for hardware on 3rd party sites. I'm yet to find a keyboard, so I really hoping this is a ribbon cable problem or connector problem on that little daughter board PCB.
If anyone has words of encouragement or past experiences in this, I'd be so grateful to learn from you. This is a very new depth of DIY work for me, so I'm quite nervous.
Thanks!
Jordan
PS And if you know anyone selling gently used laptops in Rome area of Italy, that would also be amazing 
