Phone · Samsung · Galaxy S21
Samsung Galaxy S21 Logic Board Repair
Logic Board Repair guide for the Samsung Galaxy S21
Before you begin
Tools
- Phillips #00 screwdriver
- Plastic prying tools
- Spudger tool
- Suction cup tool
- Heat gun or hair dryer
- Tweezers
- SIM eject tool
Parts / materials
- Isopropyl alcohol (91%+)
- Replacement back cover adhesive seal
- Microfiber cleaning cloth
Safety
- Disconnect the battery immediately after exposing the interior to prevent shorting components.
- Wear safety glasses when applying heat to glass panels to protect against accidental cracking.
- Do not bend or puncture the battery while working near motherboard connectors.
- Wear an anti-static wrist strap to protect sensitive integrated circuits from ESD.
Overview
Step-by-step
- 1
Eject the SIM tray
1 minInsert a SIM eject tool or paperclip into the hole next to the SIM tray on the bottom of the phone. Push firmly to pop the tray out and remove it.
- 2
Heat the rear panel
3 minUse a heat gun or hair dryer to apply mild heat around the edges of the back cover for about two minutes. This softens the adhesive securing the rear panel.
- 3
Apply a suction cup
2 minPress a suction cup onto the lower portion of the back cover near the bottom edge. Pull up gently to create a small gap between the glass and the frame.
- 4
Slice the rear adhesive
4 minInsert a plastic prying tool or pick into the seam created by the suction cup. Carefully slide it around all four edges to slice through the adhesive.
- 5
Remove the rear cover
1 minLift the rear cover straight off the chassis once all adhesive is severed. Set it aside on a clean surface.
- 6
Unscrew the top speaker cover
4 minUse a Phillips #00 screwdriver to remove the 14 screws holding down the top wireless charging coil and speaker assembly.
- 7
Remove the wireless charging assembly
2 minGently pry up the wireless charging coil and top plastic speaker housing using a plastic spudger. Lift the entire assembly away from the phone.
- 8
Disconnect the battery cable
1 minUse the flat end of a spudger to pop the battery connector straight up off the motherboard socket. This cuts power to the board to prevent short circuits.
- 9
Disconnect the main display flex cable
1 minLocate the main display ribbon cable connected to the bottom of the logic board. Pry the connector straight up with a plastic spudger.
- 10
Disconnect the interconnect flex cables
2 minDisconnect the two daughterboard interconnect flex cables from the logic board using the tip of your spudger.
- 11
Disconnect the front camera
1 minCarefully pry the front-facing camera press connector up from the top section of the logic board.
- 12
Unscrew the logic board retaining screw
1 minLocate and remove the single Phillips #00 screw securing the top portion of the logic board to the frame.
- 13
Remove the logic board
2 minGently lift the logic board out of the phone body starting from the bottom edge. Ensure no leftover cables catch on the board during removal.
- 14
Position the replacement logic board
2 minCarefully lower the new logic board into the frame, aligning the rear cameras and ports with their cutouts.
- 15
Secure the logic board screw
1 minReinstall the single Phillips #00 screw to lock the motherboard securely to the phone frame.
- 16
Reconnect all flex cables
3 minSnap the front camera, interconnect flex cables, and display cable back into their designated motherboard sockets.
- 17
Reconnect the battery
1 minPress the battery flex connector straight down onto its motherboard socket until it clicks into place.
- 18
Reinstall the wireless charging coil
4 minPlace the top speaker midframe and wireless charging coil back onto the device, aligning it properly. Secure it with the 14 Phillips #00 screws.
- 19
Reseal the back cover
3 minClean remaining old adhesive with isopropyl alcohol, apply a fresh pre-cut adhesive seal, and press the rear cover firmly into place.
After your Samsung Galaxy S21 logic board repair
Power the Galaxy S21 back on and test the logic board repair function before you put every screw away. Check touch/display response, charging, cameras, buttons, and wireless as relevant to this repair. If something fails after closing the device, reopen carefully and reseat the connectors for this Samsung Galaxy S21 job before assuming the part is defective. Keep leftover adhesive and screws labeled in case you need a second pass.
Keep learning
Explore more Samsung Galaxy S21 repair context in the encyclopedia, or open related DIY guides.

