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Dell Latitude 7420 Keyboard Replacement/Teardown

Introduction

This guide will show you how to replace the keyboard. Because the keyboard can only be replaced from the insde this is close to a teardown.

Don't be scared, its mostly unscrewing stuff. Work methodically and lay down screws in the order you used them.

If you have questions: hit me up.

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

    Edit

  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!

    Edit

  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.

    Edit

  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

    Edit

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

    • Insert wisdom here.

    Edit

  6. Dell Latitude 7420 Keyboard Replacement/Teardown, disconnect fan: step 6, image 1 of 1

    • pull horizontally to the rigt

    Edit

  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

    Edit

  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

    Edit

  10. 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

    Edit

  11. 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

    Edit

  12. Dell Latitude 7420 Keyboard Replacement/Teardown, remove motherboard screws: step 11, image 1 of 1

    • use PH1 for 2x mobo screws

    Edit

  13. 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!

    Edit

  14. 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

    Edit

  15. 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

    Edit

  16. 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

    Edit

  17. 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

    Edit

  18. 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

    Edit

  19. 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

    Edit

  20. 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

    Edit

  21. 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

    Edit

  22. 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

    Edit

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

    • keyboard backplate

    Edit

    • 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

    Edit
Conclusion

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

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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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