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Dell Latitude 7420 Keyboard Replacement/Teardown

What you need

  1. Dell Latitude 7420 Keyboard Replacement/Teardown, Remove backplate: step 1, image 1 of 2 Dell Latitude 7420 Keyboard Replacement/Teardown, Remove backplate: step 1, image 2 of 2
    • remove 8x screws with PH1 Screwdriver

    • Use finger nail or operning pick between backplate and frame at the top of the device

  2. Dell Latitude 7420 Keyboard Replacement/Teardown, Disconnect battery: step 2, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, Disconnect battery: step 2, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, Disconnect battery: step 2, image 3 of 3
    • remove battery connector by pulling up. make sure the pulling strap is turned upwards

    • remove 5x screws with PH1

    • these are longer, do not mix them up!

  3. Dell Latitude 7420 Keyboard Replacement/Teardown, Disconnect speaker cable: step 3, image 1 of 2 Dell Latitude 7420 Keyboard Replacement/Teardown, Disconnect speaker cable: step 3, image 2 of 2
    • remove speaker cable by pulling towards yourself horizontally

    • lift out the battery vertically.

  4. Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect ribbon cables: step 4, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect ribbon cables: step 4, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect ribbon cables: step 4, image 3 of 3
    • open ribbon cable connectors by lifting up and away from you the black securing latch

    • carefully lift up ribbon cables and pull towards yourself

  5. Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect headphone jack daughter board: step 5, image 1 of 1
    • Insert wisdom here.

  6. Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect fan: step 6, image 1 of 1
    • pull horizontally to the rigt

  7. Dell Latitude 7420 Keyboard Replacement/Teardown, unscrew connector plates: step 7, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, unscrew connector plates: step 7, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, unscrew connector plates: step 7, image 3 of 3
    • Use JIS00 or J00

    • display connector

    • wifi antenna connector

  8. Dell Latitude 7420 Keyboard Replacement/Teardown, unscrew connector plates: step 8, image 1 of 2 Dell Latitude 7420 Keyboard Replacement/Teardown, unscrew connector plates: step 8, image 2 of 2
    • use JIS00 or J00

    • unscrew connector plate

  9. Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect cables: step 9, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect cables: step 9, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect cables: step 9, image 3 of 3
    • lift upwards vertically

    • pull out horizontally away from you

  10. Dell Latitude 7420 Keyboard Replacement/Teardown, remove heat sink: step 10, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, remove heat sink: step 10, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, remove heat sink: step 10, image 3 of 3
    • remove 6x screws using PH1

    • remove cable sticker from heat sink

    • if the thermal paste has dried out the heat sink can be stuck on. carefully wiggle it horizontally until you can lift it up vertically

  11. Dell Latitude 7420 Keyboard Replacement/Teardown, remove motherboard screws: step 11, image 1 of 1
    • use PH1 for 2x mobo screws

  12. Dell Latitude 7420 Keyboard Replacement/Teardown, remove USB C screws: step 12, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, remove USB C screws: step 12, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, remove USB C screws: step 12, image 3 of 3
    • remove 4x USB Screws with PH1

    • these are longer, do not mix them up!

  13. Dell Latitude 7420 Keyboard Replacement/Teardown, USB C daughter board screws: step 13, image 1 of 2 Dell Latitude 7420 Keyboard Replacement/Teardown, USB C daughter board screws: step 13, image 2 of 2
    • remove 2x with PH1

  14. Dell Latitude 7420 Keyboard Replacement/Teardown, remove motherboard: step 14, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, remove motherboard: step 14, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, remove motherboard: step 14, image 3 of 3
    • start on the right side at the USB C daughter board.

    • lift up the motherboard where the fan used to be

    • you should be able disconnect the daughterboard and mother board

    • the USB C port on the left might be tight. Use your fingers to slightly bend the laptop casing outward to the left above the usb c port

    • lift out the motherboard vertically

    • lift out USB C daughter board vertically. use the frame bending trick if necessary

  15. Dell Latitude 7420 Keyboard Replacement/Teardown, remove headphone jack daughter board: step 15, image 1 of 1
    • remove 1x screw with PH1

    • lift out daughter board vertically

  16. Dell Latitude 7420 Keyboard Replacement/Teardown, unstick ribbon cables: step 16, image 1 of 2 Dell Latitude 7420 Keyboard Replacement/Teardown, unstick ribbon cables: step 16, image 2 of 2
    • carefully unstick glued on ribbon cables. use are card and pull up at 45° angle

    • no need to remove headphone jack cable

    • disconnect ribbon cable

    • be extremly careful not to pull at bends in the ribbon cables

  17. Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect keyboard ribbon cables: step 17, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect keyboard ribbon cables: step 17, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect keyboard ribbon cables: step 17, image 3 of 3
    • open connector as usual

    • the smaller ribbon cable has a different securing mechanism, look at the second image. it is opend from the other side

    • open connector from smaller ribbon cable at the white flap. NOT on top of the ribbon cable!

    • pull out ribbon cables

  18. Dell Latitude 7420 Keyboard Replacement/Teardown, remove keyboard backplate screws: step 18, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, remove keyboard backplate screws: step 18, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, remove keyboard backplate screws: step 18, image 3 of 3
    • use JIS00 or J00 to remove 19x screws

    • go around perimeter of the backplate in a orderly fashion when removing the screws to not miss any

  19. Dell Latitude 7420 Keyboard Replacement/Teardown, remove keyboard with backplate: step 19, image 1 of 2 Dell Latitude 7420 Keyboard Replacement/Teardown, remove keyboard with backplate: step 19, image 2 of 2
    • lift up keyboard vertically

    • be careful: ribbon cables might be sticky

  20. Dell Latitude 7420 Keyboard Replacement/Teardown, removing keyboard from backplate: step 20, image 1 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, removing keyboard from backplate: step 20, image 2 of 3 Dell Latitude 7420 Keyboard Replacement/Teardown, removing keyboard from backplate: step 20, image 3 of 3
    • use PH1 to unscrew backplate from front of keyboard

  21. Dell Latitude 7420 Keyboard Replacement/Teardown, clean CPU and Heat Sink: step 21, image 1 of 2 Dell Latitude 7420 Keyboard Replacement/Teardown, clean CPU and Heat Sink: step 21, image 2 of 2
    • remove old thermal paste using isopropyl alcohol and a cloth

    • apply new thermal paste

  22. Dell Latitude 7420 Keyboard Replacement/Teardown, backplate: step 22, image 1 of 1
    • keyboard backplate

    • when you are done with reassembly do not panic, the first boot takes a little longer after disconnecting the battery

    • after reassembly press inbetween keyboard keys to klick together backplate and notebook frame

Conclusion

To reassemble your device, follow these instructions in reverse order.

3 other people completed this guide.

fixer

Member since: 07/05/16

862 Reputation

3 Guides authored

2 Comments

Steps 10 and 13 are not necessary (motherboard could be removed together with a head sink)

Alex - Reply

After following this very useful guide my new keyboard was not working, when you reconnect all the ribbon cable take some time to reconnect them better then I have done :-D

If something is not working double check the ribbon cables connection before doing anything else.

daniele - Reply

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