Disassembly/Repair of the mobile device Samsung Galaxy M31 SM-M315 with each step description and the required set of tools.

⚠️ Before disassembling, do not forget to turn your phone off.

Use the Key tool (aka Needle) or Paperclip. Push the tip all the way into the hole until the tray ejects, and then pull the tray of SIM and Memory card (Micro SD) out.

ℹ️️ Remember the location for the SIM and Memory card (Micro SD) trays so that nothing is confused when reassembling.

⚠️ Pay attention! The tool must be inserted into a hole on the edge of the phone's housing. Do not press too hard. It may break the tray eject mechanism.

Using a spudger or a plastic pick, carefully, around the edge, detach the back cover clips, and remove it.

Do not insert the tool deeply or bend it. Otherwise, the housing may be tampered with or damaged.

⚠️ Be careful when opening the cover from the volume and power buttons side. Thin cable and fragile buttons are straightforward to damage.

⚠️ Look in advance in the picture for the cables’ location for inter-board, touchscreen, display, buttons (if any) under the cover to not damage them accidentally.

⚠️ Pay attention to the fingerprint sensor cable glued to the back cover from the inside.

Disconnect the connector and remove the fingerprint sensor.

Using a screwdriver (Phillips 1.5 mm PH000), unscrew the seven screws.

Remove the cover with antennas that protect the printed circuit board (PCB). Try to lift the covers by the edges and not push anything between them to not accidentally touch or short-circuit anything on the PCB.

ℹ️️ On the upper cover, you can see the metalized coating on the plastic in the form of tracks and contact pads. These are Wi-Fi, Bluetooth, and GPS antennas.

⚠️ It is crucial while reassembling, checking the spring contacts on the board, and the contact pads on the cover match and touch. Otherwise, signal loss or signal may be quite weak.

Disconnect the battery connector as soon as possible.

ℹ️️ The Samsung Galaxy M31 SM-M315 model has a battery EB-BM207ABY with 6000 mAh capacity (aka rechargeable battery).

⚠️ It is highly recommended to disconnect the connector to avoid possible short circuits during disassembly. Also, try not to use a metal tool to disconnect the rechargeable battery connector or do it carefully.

Using a screwdriver (Phillips 1.5 mm PH000), unscrew eight screws.

ℹ️️ Be sure to note the location of the screws before disassembling. When assembling the device, screwing the screw in the wrong place may damage the device or its parts. To avoid damage, the removed screws and individual pieces (as gaskets or brackets) must be laid out in the appropriate order, or the screws and their holes in the phone must be marked with colored markers.

Remove the cover protecting the daughterboard (aka sub-board). Try to lift the cover by the edges and do not push anything between the cover and PCB to not accidentally touch or short-circuit anything on the board.

Carefully, preferably from the edge, disconnect the connectors and remove the inter-board cables connecting the mainboard to the daughterboard (also known as the sub-board).

⚠️ Be careful when removing the cables from the connectors, the cables are pretty thin, and it is easy enough to break them or damage the contact tracks inside.

ℹ️️ An arrow on the FFC cable (flexible flat cable) indicates its correct position.

Disconnect the coaxial cable connector.

Remove the sub-board. It is glued to the frame with metalized tape, so to facilitate the process, the board can be heated a bit.

ℹ️️ The board contains a charging port (Micro USB), microphone, vibration motor, spring contacts for the speaker, and an antenna unit.

⚠️ It is not necessary to insert the tool under the board when removing the sub-board. Internal components could be damaged.

Disconnect the connectors and remove one rear camera and one front (selfie) camera.

Using a screwdriver (Phillips 1.5 mm PH000), unscrew one screw.

Disconnect the coaxial cable connector and connector of the power and volume -/+ buttons.

Carefully remove the printed circuit board. There is no need to use a lever or try to reach the board by force. Make sure that nothing is getting in the way or holding the board.

⚠️ Do not bend the circuit board when removing it or push tools under it. Unbeknownst to yourself, you can damage components or cables from the inside.

Disconnect connectors and remove the assembly of three rear cameras.