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LG CU400 Charging Port Replacement

Introduction

This guide will walk you through the steps to remove the charging port from your LG CU400. It will help remove the battery, the lower half casing, the removal of the motherboard from the phone casing, and the removal and replacement of the charging port on the motherboard. Before doing this, be aware that you will be unable to use your phone until the replacement is complete and the phone fully reassembled. You should also be careful when handling the motherboard because it has delicate wires extending from it. This guide also requires a soldering iron that can be dangerous to use. The following video has information on micro soldering: https://www.youtube.com/watch?v=jGZKsuaJ...

What you need

  1. LG CU400 Charging Port Replacement, Battery: step 1, image 1 of 2 LG CU400 Charging Port Replacement, Battery: step 1, image 2 of 2

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

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  2. LG CU400 Charging Port Replacement: step 2, image 1 of 3 LG CU400 Charging Port Replacement: step 2, image 2 of 3 LG CU400 Charging Port Replacement: step 2, image 3 of 3

    • Slide the rear cover towards you.

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  3. LG CU400 Charging Port Replacement: step 3, image 1 of 2 LG CU400 Charging Port Replacement: step 3, image 2 of 2

    • 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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  4. LG CU400 Charging Port Replacement, Bottom Half Assembly: step 4, image 1 of 2 LG CU400 Charging Port Replacement, Bottom Half Assembly: step 4, image 2 of 2

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

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  5. LG CU400 Charging Port Replacement: step 5, image 1 of 2 LG CU400 Charging Port Replacement: step 5, image 2 of 2

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

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  6. LG CU400 Charging Port Replacement: step 6, image 1 of 2 LG CU400 Charging Port Replacement: step 6, image 2 of 2

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

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  8. LG CU400 Charging Port Replacement: step 7, image 1 of 2 LG CU400 Charging Port Replacement: step 7, image 2 of 2

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

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  9. LG CU400 Charging Port Replacement: step 8, image 1 of 3 LG CU400 Charging Port Replacement: step 8, image 2 of 3 LG CU400 Charging Port Replacement: step 8, image 3 of 3

    • 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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  10. LG CU400 Charging Port Replacement: step 9, image 1 of 2 LG CU400 Charging Port Replacement: step 9, image 2 of 2

    • 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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  11. LG CU400 Charging Port Replacement, Motherboard: step 10, image 1 of 3 LG CU400 Charging Port Replacement, Motherboard: step 10, image 2 of 3 LG CU400 Charging Port Replacement, Motherboard: step 10, image 3 of 3

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

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  12. LG CU400 Charging Port Replacement: step 11, image 1 of 2 LG CU400 Charging Port Replacement: step 11, image 2 of 2

    • 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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  13. LG CU400 Charging Port Replacement: step 12, image 1 of 1

    • 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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  14. LG CU400 Charging Port Replacement: step 13, image 1 of 1

    • 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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  15. LG CU400 Charging Port Replacement: step 14, image 1 of 1

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

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  16. LG CU400 Charging Port Replacement: step 15, image 1 of 3 LG CU400 Charging Port Replacement: step 15, image 2 of 3 LG CU400 Charging Port Replacement: step 15, image 3 of 3

    • 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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  17. LG CU400 Charging Port Replacement, Charging Port: step 16, image 1 of 1

    • Locate the 6 locations that need to be desoldered.

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  18. LG CU400 Charging Port Replacement: step 17, image 1 of 2 LG CU400 Charging Port Replacement: step 17, image 2 of 2

    • Using a desoldering braid and a soldering iron, remove the soldered connections. Use the website " How To Solder and Desolder Connections " for more information on soldering.

    • When attaching the new charging port, use the solder and not the desoldering braid to make the conection.

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  19. LG CU400 Charging Port Replacement: step 18, image 1 of 1

    • You will need to coat the boxed area with flux liquid and then heat it with a heat gun while gently prying the charging port with the micro soldering tweezers. Use the video https://www.youtube.com/watch?v=jGZKsuaJ... for more information on micro soldering.

    • Make sure to watch the video to see how to micro solder the new charging port on.

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Conclusion

To reassemble your device, follow these instructions in reverse order, but refer to specific step's reminders.

Author

with 3 other contributors

Ross Brown

Member since: 10/03/16

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Team

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

IUPUI-HARLEY-F16S1G3

4 Members

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