Keyboard problem on Dell Inspiron

[Colin21958]

I have a Dell E1405 Inspiron, I refurbished it adding an updated (64 bit) CPU (T5500) among other things; I should mention I bought a job lot of 4 of the same laptop and did exactly the same with all of them. I also added an SSD and installed Windows 10. They all worked fine and I have since sold two of them. However, one developed a shorted motherboard; I'm looking into that, but the other one, which had been working just fine and I had put on sale, suddenly developed a keyboard problem. When you type r you get r5, q gets q', u gets u6 and so on. It's only the top two rows of the keyboard that do this. So I checked the on screen keyboard and that was fine, I added an external wireless keyboard and that too was fine. I therefore felt it was the keyboard, so I swapped it with all the other three i had in turn (which were working fine on the other laptops) but I got the same result with all of them. So it clearly isn't a keyboard problem, so I presumed it must be a problem with the SIO chip. I therefore replaced that, but it's still the same! I'm now tearing my hair out! I have found several reports of people having this exact same problem on the internet with various laptops, but not one where they found a solution! (Or at least if they did, they didn't share it!) If anyone has any ideas (other than installing drivers, which of course doesn't work) I would be very pleased to hear from them. If I at least had a different problem after fitting the new chip I could have said it must have been that, but with exactly the same problem, clearly that it VERY unlikely! Help, please!

[piernov]

Re: Keyboard problem on Dell Inspiron

KB connector or debouncing cap maybe.

[Colin21958]

Re: Keyboard problem on Dell Inspiron

Thanks for the suggestion, I'll look into the connector, though I did think about the connection itself and with the number of times I changed it, with different keyboards, etc., it seems unlikely to be a connection problem, but I will scrutinise the connection to make sure. Please could you elaborate on the capacitor idea? What exactly would I be looking for? There are no shorted capacitors for sure... Thanks again...

[Colin21958]

Re: Keyboard problem on Dell Inspiron

After much investigation I have found that by disconnecting the touch pad from the motherboard the keyboard works fine! So, it looks like it might be something to do with the touchpad! I will update when I get to the bottom of it!

[Colin21958]

Re: Keyboard problem on Dell Inspiron

Fixed! It was the touchpad ribbon cable! Swapped it with another one and it all works fine! Seems very strange that the touchpad cable should affect the keyboard operation, especially as the touchpad and buttons were working fine! Who knows!