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iPhone 4S Logic Board Replacement

Introduction

Use this guide to replace your iPhone's logic board.

What you need

  1. iPhone 4S Logic Board Replacement, Rear Panel: step 1, image 1 of 1

    • Before you begin, discharge your iPhone battery below 25%. A charged lithium-ion battery can catch fire and/or explode if accidentally punctured.

    • Power off your iPhone before beginning disassembly.

    • Remove the two 3.6 mm Pentalobe P2 screws next to the dock connector.

    • Be sure the driver is well-seated when removing Pentalobe screws—they are easy to strip.

    Edit

  2. iPhone 4S Logic Board Replacement: step 2, image 1 of 2 iPhone 4S Logic Board Replacement: step 2, image 2 of 2

    • Push the rear panel toward the top edge of the iPhone.

    • The panel will move about 2 mm.

    Edit

  3. iPhone 4S Logic Board Replacement: step 3, image 1 of 1

    • Pull the rear panel away from the back of the iPhone, being careful not to damage the plastic clips attached to the rear panel.

    • Remove the rear panel from the iPhone.

    Edit

  4. iPhone 4S Logic Board Replacement, Battery: step 4, image 1 of 2 iPhone 4S Logic Board Replacement, Battery: step 4, image 2 of 2

    • Remove the following screws securing the battery connector to the logic board:

    • One 1.7 mm Phillips screw

    • One 1.5 mm Phillips screw

    Edit

  5. iPhone 4S Logic Board Replacement: step 5, image 1 of 3 iPhone 4S Logic Board Replacement: step 5, image 2 of 3 iPhone 4S Logic Board Replacement: step 5, image 3 of 3

    • Carefully push the pressure contact away from the battery connector until it slides free from its position.

    • Remove the pressure contact.

    Edit

  6. iPhone 4S Logic Board Replacement: step 6, image 1 of 3 iPhone 4S Logic Board Replacement: step 6, image 2 of 3 iPhone 4S Logic Board Replacement: step 6, image 3 of 3

    • Use a plastic opening tool to gently pry up the battery connector from its socket on the logic board.

    • Place the tip of the tool between the loudspeaker enclosure and the metal cover of the connector, and lift the bottom edge of the connector first.

    • The battery connector comes off vertically from the logic board. Do not apply force sideways.

    • Be careful not to pry at the battery connector socket itself, or it may detach from the logic board. There are four very small solder points awaiting this mistake!

    Edit

  7. iPhone 4S Logic Board Replacement, Reassembly tip: step 7, image 1 of 2 iPhone 4S Logic Board Replacement, Reassembly tip: step 7, image 2 of 2

    • During reassembly, be sure to carefully position the pressure contact back in place. It should rest on top of the Philips screw post shown, and the gold contact should point towards the battery connector.

    • Be sure to clean the pressure contact with a degreaser such as windex or isopropyl alcohol. The oils on your fingers have the potential to create wireless interference.

    Edit

  8. iPhone 4S Logic Board Replacement: step 8, image 1 of 2 iPhone 4S Logic Board Replacement: step 8, image 2 of 2

    • Insert the edge of a plastic opening tool between the battery and the outer case near the bottom of the iPhone.

    • Run the plastic opening tool along the right edge of the battery and pry up at several points to completely separate it from the adhesive securing it to the outer case.

    • If the adhesive is too strong, apply a few drops of high concentration (over 90%) isopropyl alcohol under the edge of the battery.

    • Wait about one minute for the alcohol solution to weaken the adhesive.

    • Use the flat end of a plastic opening tool to gently lift the battery.

    • Don't try to forcefully lever the battery out. If needed, apply a few more drops of alcohol to further weaken the adhesive. Never deform or puncture the battery with your pry tool.

    • If there's any alcohol solution remaining in the phone, carefully wipe it off or allow it to air dry before installing your new battery.

    Edit

  9. iPhone 4S Logic Board Replacement: step 9, image 1 of 2 iPhone 4S Logic Board Replacement: step 9, image 2 of 2

    • Use the exposed clear plastic pull tab to peel the battery off the adhesive securing it to the iPhone.

    • Be careful not to pull the plastic pull tab too hard as it can be ripped off very easily.

    • Remove the battery.

    • If your replacement battery came in a plastic sleeve, remove it before installation by pulling it away from the ribbon cable.

    • If your replacement battery came with an uncreased cable, carefully crease the cable into the proper shape before installing the battery into the phone.

    • While installing the replacement battery, temporarily connect the battery connector to the phone to ensure proper alignment. Once the battery is glued in place, disconnect the battery connector.

    • Perform a hard reset after reassembly. This can prevent several issues and simplify troubleshooting.

    Edit

  11. iPhone 4S Logic Board Replacement, Dock Connector Cable: step 10, image 1 of 2 iPhone 4S Logic Board Replacement, Dock Connector Cable: step 10, image 2 of 2

    • Remove the following screws securing the dock connector cable cover to the logic board:

    • One 1.5 mm Phillips screw

    • One 1.2 mm Phillips screw

    • Remove the metal dock connector cable cover.

    Edit

  12. iPhone 4S Logic Board Replacement: step 11, image 1 of 1

    • Use the edge of a plastic opening tool to pry the dock cable up from its socket on the logic board.

    Edit

  13. iPhone 4S Logic Board Replacement: step 12, image 1 of 1

    • Peel the dock connector cable off the adhesive securing it to the logic board and the side of the speaker enclosure.

    Edit

  14. iPhone 4S Logic Board Replacement: step 13, image 1 of 2 iPhone 4S Logic Board Replacement: step 13, image 2 of 2

    • Use the edge of a plastic opening tool to pry the cellular antenna cable up from its socket on the logic board.

    • De-route the cellular antenna cable out from under the metal fingers attached to the logic board.

    Edit

  15. iPhone 4S Logic Board Replacement, Rear Camera: step 14, image 1 of 1
    Tool used on this step:
    Tweezers
    $4.99
    Buy

    • Be wary of the outer plastic ring located on top of the rear camera's flash assembly. It can be easily displaced if not removed during disassembly.

    • You can use tweezers, a plastic opening tool, or a spudger to remove the outer plastic ring.

    Edit

  16. iPhone 4S Logic Board Replacement: step 15, image 1 of 1

    • Remove the following four screws securing the cable cover to the logic board:

    • One 2.7 mm Phillips screw

    • One 2.6 mm Phillips screw

    • One 1.3 mm Phillips screw

    • One 1.2 mm Phillips screw

    Edit

  17. iPhone 4S Logic Board Replacement: step 16, image 1 of 2 iPhone 4S Logic Board Replacement: step 16, image 2 of 2

    • Use the edge of a plastic opening tool to pry the cable cover tabs out of their slots cut into the EMI shield on the logic board.

    • Lift the cable cover from its edge nearest the top and remove it from the iPhone.

    Edit

  18. iPhone 4S Logic Board Replacement: step 17, image 1 of 2 iPhone 4S Logic Board Replacement: step 17, image 2 of 2

    • Use the edge of a plastic opening tool to pry the rear camera connector up from its socket on the logic board.

    • Be careful not to break any components off the surrounding area on the logic board as you pry upwards.

    • Remove the rear camera from the iPhone.

    • There is a small rubber gasket that sits underneath the rear-facing camera. Make sure that it is properly seated before reassembly.

    Edit

  19. iPhone 4S Logic Board Replacement, SIM Card: step 18, image 1 of 2 iPhone 4S Logic Board Replacement, SIM Card: step 18, image 2 of 2

    • Use a SIM eject tool or a paperclip to eject the SIM and its tray.

    • This may require a significant amount of force.

    • Remove the SIM and its tray.

    Edit

  20. iPhone 4S Logic Board Replacement, Logic Board: step 19, image 1 of 2 iPhone 4S Logic Board Replacement, Logic Board: step 19, image 2 of 2

    • Remove the five cables near the top of the logic board in the following order:

    • Headphone jack/volume button cable

    • Front facing camera cable

    • Digitizer cable

    • Display data cable

    • Power button cable (located underneath the headphone jack/volume button cable as shown in the second picture.)

    • To disconnect the cables, use the edge of a plastic opening tool to gently lift their connectors up and out of the sockets on the logic board.

    • Be careful not to break any of the small and delicate surface mount components as you disconnect the cables.

    Edit

  21. iPhone 4S Logic Board Replacement: step 20, image 1 of 1

    • Remove the 1.5 mm Phillips screw securing the grounding clip to the logic board near the headphone jack.

    Edit

  22. iPhone 4S Logic Board Replacement: step 21, image 1 of 2 iPhone 4S Logic Board Replacement: step 21, image 2 of 2

    • Use the tip of a spudger to pry the small grounding clip up off the logic board.

    • Carefully grasp the grounding clip and remove it from the iPhone.

    • Before reassembly, be sure to clean all metal-to-metal contact points on the grounding clip (not the mating halves of connectors) with a de-greaser such as windex or isopropyl alcohol. The oils on your fingers have the potential to cause grounding issues.

    Edit

  23. iPhone 4S Logic Board Replacement: step 22, image 1 of 1
    Tool used on this step:
    Standoff Screwdriver for iPhones
    $5.49
    Buy

    • Remove the 4.8 mm standoff screw near the headphone jack.

    • Standoff screws are best removed using a standoff screwdriver or bit.

    • In a pinch, a small flathead screwdriver will do the job—but use extra caution to ensure it doesn't slip and damage surrounding components.

    Edit

  24. iPhone 4S Logic Board Replacement: step 23, image 1 of 1

    • Use the edge of a plastic opening tool to disconnect the Wi-Fi antenna from the logic board.

    Edit

  25. iPhone 4S Logic Board Replacement: step 24, image 1 of 2 iPhone 4S Logic Board Replacement: step 24, image 2 of 2

    • If present, peel the piece of black tape covering the hidden screw near the power button.

    • Remove the 2.6 mm Phillips screw securing the logic board near the power button.

    • (Use caution when removing this screw and removing the power contact held by it; the contact tab will come loose with the screw)

    • Notice the small rubber bumper under the screen & digitizer cables (which are detached at top above the Q-code). This bumper can fall off of the logic board when removed or get stuck to the cables and fall off later.

    Edit

  26. iPhone 4S Logic Board Replacement: step 25, image 1 of 1

    • Remove the following screws securing the logic board to the case:

    • One 2.5 mm Phillips screw near the vibrator motor

    • One 2.4 mm Phillips screw

    • One 3.6 mm standoff along the side of the logic board nearest the battery opening.

    • Use a standoff driver bit and driver handle to remove the single 3.6 mm standoff screw.

    • In a pinch, a small flathead screwdriver will do the job—but use extra caution to ensure it doesn't slip and damage surrounding components.

    Edit

  27. iPhone 4S Logic Board Replacement: step 26, image 1 of 1

    • Carefully lift the logic board from the end closest to the speaker enclosure and slide it away from the top edge of the iPhone.

    • Remove the logic board.

    • Before reassembly, be sure to clean all metal-to-metal contact points on the logic board (not the mating halves of connectors) with a de-greaser such as windex or isopropyl alcohol. The oils on your fingers have the potential to cause grounding issues.

    • There is a small rubber bumper that sits on the top edge of the logic board where the digitizer and screen cables come through the case. It protects the cables as they bend over the top of the logic board. This can either get stuck to the cables or fall off the logic board when it comes out. Look back over step 22 for more details.

    Edit

  28. iPhone 4S Logic Board Replacement: step 27, image 1 of 1

    • Be sure not to lose the small grounding finger for the rear facing camera near the power button. This finger rests on top of the PCB, screwed down, and covered with the adhesive black plastic tape.

    Edit
Conclusion

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

256 other people completed this guide.

12 Comments

recently I tried to fix my wifi antenna and ended up disturbing something that made my touch unresponsive. Okay just to make sure that my Display unit was not damaged I plugged in another display set and still the touch was not working!

what could have possibly gone wrong?

Sourabh Salke - Reply

What can I say but BRILLIANT!!!!

You have saved me a bomb - very easy and much appreciated!

dbgraphiteartist - Reply

wonderful description's steps..Don't stop..forwards gentelman

AbdelHadi - Reply

I had 2 broken iPhones and thanks to this guide I have a working one and a load of pieces :-)

David Garcia Watkins - Reply

Thank you very much for these instructions, which are aircraft maintenance quality. I had 2 phone: one with broken front glass and bad battery but with 32G. Other one good conditions but only 16G, which left over after getting 5s. So I changed logic board assembly from 32G to other frame and left all the rest inside. Voila, there it is fixed 32G 4s phone ready to use after recharging battery.

Instructions are so good that it takes me about 1 1/2 hour to disassembly and reassembly 2 phones and I had´t done that ever before. I just read instructions first and then followed step by step and checked out comments.

Samuel Lackman - Reply

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