Issue with Chromebook 14 (CB3-431)

keir311291
keir311291 Member Posts: 2 New User
edited November 2023 in 2018 Archives
first of all if this is in the wrong place or has been answered im sorry i did have a look before but couldn't find anything.

so this is my issue. basically i like repairing laptops etc its interesting to me i don't do it as a business just as favours for Friends, iv got quite good at it and id say 97% of the time i can fix an issue and have a pc working fine again. im not saying this to be big headed its just so you understand i have tried LOTS of methods to get this issue fixed.

So i got a Chromebook 14 CB3-431 that had been water damaged but still powered on and worked, and the listing said the keyboard played up and would type random letters or cause the Chromebook to power off.

so i received the Chromebook, replaced the keyboard first of all as the rest of the components worked perfectly and this didn't help. some letters would not type at all, some letter cause multiple letters to appear on screen and other letters when pressed caused the Chromebook to physically power off. its important to not that it did the same thing with the original keyboard as well as the replacement i bought. i discovered the only way to get the Chromebook to work without issue was to detached the keyboard ribbon cable from the motherboard. and i have been using it with a small Bluetooth keyboard sat atop the physical keyboard with no issue now for about 4 months.

naturally with the issue persisting with both anew and old keyboard i presumed that with the Chromebook being water damaged it had affected the motherboard and i would just wait for a replacement motherboard to come online and last week one did. 

now hears where it gets interesting, a motherboard - completely the right one for my model of Chromebook does EXACTLY the same thing with the keyboard as i have described above.

i assumed it was another component causing the issue and have tried powering on the Chromebook with each component inside detached from the motherboard and the exact same issue occurs. i have even tried disconnecting the screen and using a HDMI connection, the same thing happens

at this point i am open to suggestions or possible fixes that may help me out. in total i have spent less that £100 GBP on this so if it cannot be fix its fine its just annoying me that i cant find what it is! 

thanks in advance for any potential fixes

Keir 

Comments

  • billsey
    billsey ACE Posts: 35,029 Trailblazer
    I haven't been inside that model, but if you have two motherboards and two keyboards and the cable between them is bonded to the keyboard as is typical I think you should be looking at physical mounting issues that might put pressure on the keyboard when everything is assembled. Perhaps it's twisted just enough to muck with the contact grids that convert key presses into the signals sent to the motherboard. Often the chicklet keyboards are designed with overlapping layers of plastic that have conductive pads so when a key is pressed it forces contact between two layers. Bending the layers of plastic might allow more than one point of contact when pressing only one key, which can do weird things.
    Click on "Like" if you find my answer useful or click on "Yes" if it answers your question.
  • keir311291
    keir311291 Member Posts: 2 New User
    interesting i will have a look into this thanks very much for your replay.

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