Introduction

This guide will show you how to remove and replace the hinge of the LG CU400. The hinge holds the phone together and is responsible for the spring action of the flip phone. This repair would need to happen if the phone would not close or is in two pieces.

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  • Push the button labeled 'PUSH' on the rear cover.

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  • Slide the rear cover towards you.

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Image 1/2: When installing the new battery, have the metal contacts of the phone match up with the metal contacts of the battery. Image 2/2: When installing the new battery, have the metal contacts of the phone match up with the metal contacts of the battery.
  • To remove the battery, grasp the top front edge of the battery and pull the battery away from the phone.

  • When installing the new battery, have the metal contacts of the phone match up with the metal contacts of the battery.

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  • Remove the sim card by sliding the card out from under the retainer using either your fingers or a spudger.

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  • Remove the rubber covers in the highlighted locations using a metal spudger.

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  • Remove the six 3mm #000 flat Phillips head screws from the back of the phone using a Phillips #000 Screwdriver.

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  • Remove the headphone jack cover with your finger or metal spudger.

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Image 1/3: Pry gently as to not break the plastic clips that hold the two assemblies together. Image 2/3: Work your way around the perimeter of the phone with the metal spudger to separate the two assemblies. Image 3/3: Work your way around the perimeter of the phone with the metal spudger to separate the two assemblies.
  • Insert the metal spudger between the keypad assembly and back cover assembly and pry the two assemblies apart.

  • Pry gently as to not break the plastic clips that hold the two assemblies together.

  • Work your way around the perimeter of the phone with the metal spudger to separate the two assemblies.

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  • Once you have worked your way around the perimeter of the phone, you will have access to the components in the bottom half assembly.

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  • You should notice that the number pad is loose and can simply be taken out of the open phone casing.

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Image 1/2: There are copper ribbon cables connected to each side of the motherboard leading to the buttons for volume control and the camera that need slid out of the phone casing as the motherboard is being removed. Image 2/2: There are three in total, but do not remove the top one from the phone casing yet.
  • Using the spudger, start to gently pry the motherboard from the back of the phone and work your way around the perimeter of the motherboard.

    • There are copper ribbon cables connected to each side of the motherboard leading to the buttons for volume control and the camera that need slid out of the phone casing as the motherboard is being removed.

      • There are three in total, but do not remove the top one from the phone casing yet.

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Image 1/1: Use tweezers to grab the black piece that these wires are attached to and simply pull it off the motherboard.
  • Once the motherboard is not locked in place it will still be attached to the back phone casing by two wires, red and black, twisted together.

  • Use tweezers to grab the black piece that these wires are attached to and simply pull it off the motherboard.

    • You may need to flip the phone over so that the screen is facing down. Feel free to move the keypad assembly to the closed position for this step.

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Image 1/1: Make sure to lift it so that you are pulling the entire thing off at once and not pulling off the flat piece at an angle.
  • Remove the display ribbon cable from the back of the motherboard using tweezers.

    • Make sure to lift it so that you are pulling the entire thing off at once and not pulling off the flat piece at an angle.

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  • Use tweezers to remove the top ribbon cable, mentioned in step 11, from the hinge area.

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Image 1/3: The motherboard should be completely free of the phone casing, and you should have what is shown in the pictures. Image 2/3: The motherboard should be completely free of the phone casing, and you should have what is shown in the pictures. Image 3/3: The motherboard should be completely free of the phone casing, and you should have what is shown in the pictures.
  • Grasp either side of the motherboard and gently lift it away from the phone casing.

  • The motherboard should be completely free of the phone casing, and you should have what is shown in the pictures.

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  • Remove the four rubber covers from the front screen using a metal spudger.

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  • Remove the four 3mm #000 flat Phillips head screws from the front screen using a Phillips #000 Screwdriver.

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Image 1/3: Continue to work around the perimeter of the phone with the metal spudger. Image 2/3: Once you have worked around the perimeter of the phone you should have two halves to the top assembly, the screen assembly and the cover. Image 3/3: Once you have worked around the perimeter of the phone you should have two halves to the top assembly, the screen assembly and the cover.
  • Insert the metal spudger in the seam on the top assembly. This will pry the two pieces apart from each other.

  • Continue to work around the perimeter of the phone with the metal spudger.

  • Once you have worked around the perimeter of the phone you should have two halves to the top assembly, the screen assembly and the cover.

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Image 1/3: Using tweezers, carefully disconnect the display ribbon cable from the screen assembly and phone by lifting up on both connections. Image 2/3: The display ribbon cable will still be attached to the phone via the hinge. The disconnection of the display ribbon cable in this step is to remove the screen from the screen assembly. Image 3/3: The display ribbon cable will still be attached to the phone via the hinge. The disconnection of the display ribbon cable in this step is to remove the screen from the screen assembly.
  • Set aside the cover half.

  • Using tweezers, carefully disconnect the display ribbon cable from the screen assembly and phone by lifting up on both connections.

  • The display ribbon cable will still be attached to the phone via the hinge. The disconnection of the display ribbon cable in this step is to remove the screen from the screen assembly.

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  • Grip the screen and ear speaker connected to the screen via red and black wires, and carefully pull the screen away from the screen assembly.

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  • Using tweezers, pull the gray plastic piece that is going around the flex cable out of the hinge area.

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Image 1/2: This piece will not be completely removed. Image 2/2: This piece will not be completely removed.
  • Using the tweezers, slide the metal piece along the center line of the hinge until it clicks into place.

  • This piece will not be completely removed.

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  • You can now carefully pull apart the phone casing at the hinge by separating them at the left side of the hinge.

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Conclusion

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

Ibrahim Momoh

Member since: 10/03/2016

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IUPUI, Team 1-3, Harley Fall 2016 Member of IUPUI, Team 1-3, Harley Fall 2016

IUPUI-HARLEY-F16S1G3

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