Phone · Motorola · Moto E40
Motorola Moto E40 Logic Board Repair
Logic Board Repair guide for the Motorola Moto E40
Before you begin
Tools
- SIM eject tool
- Plastic opening pick
- Phillips #00 screwdriver
- ESD-safe spudger
- Precision tweezers
- Fine-tip soldering iron
- Magnifying glass or headlamp
Parts / materials
- Soldering flux
- Desoldering braid
- 99% Isopropyl alcohol
- Lint-free swabs
Safety
- Wear an anti-static ESD wrist strap while handling exposed circuit boards.
- Operate soldering equipment in a well-ventilated area to avoid inhaling flux fumes.
- Always disconnect the battery before touching electrical logic board components.
Overview
Step-by-step
- 1
Power Off and Eject SIM Tray
2 minTurn off the phone completely. Insert a SIM eject tool into the tray hole on the left edge to remove the SIM and microSD tray.
- 2
Unclip Rear Cover
5 minInsert a plastic opening pick into the seam between the screen assembly and rear cover. Slide the pick around the perimeter to release the plastic clips.
- 3
Disconnect Fingerprint Sensor Cable
2 minSlightly lift the rear cover to access the fingerprint sensor flex cable. Use a plastic spudger to pry the cable connector straight up from the board.
- 4
Remove Upper Bracket Screws
4 minUse a Phillips #00 screwdriver to remove the screws holding down the upper motherboard protective cover.
- 5
Remove Upper Motherboard Shield
2 minGently lift and remove the plastic upper shield to expose the logic board and connectors.
- 6
Disconnect Battery Press Connector
1 minUse the edge of an ESD-safe spudger to pop the battery connector straight up from its socket on the logic board.
- 7
Disconnect Display and Main Flex Cables
2 minPry up the display flex connector and the main interconnect flex cable connectors attached to the lower portion of the logic board.
- 8
Disconnect Antenna Coaxial Cable
2 minGrasp the antenna cable head with precision tweezers and gently lift it straight up to unseat it from the logic board.
- 9
Remove Logic Board Retaining Screws
3 minUnscrew the remaining Phillips #00 screws securing the logic board directly to the phone frame.
- 10
Remove Logic Board from Frame
3 minCarefully pry under the edges of the logic board with a spudger and lift it clear from the chassis.
- 11
Inspect Board under Magnification
5 minPlace the logic board under a magnifying lamp and inspect for corroded joints, burnt traces, or damaged components.
- 12
Apply Liquid Flux to Damaged Components
2 minDispense a small amount of liquid soldering flux directly over the affected solder pads or surface-mount components.
- 13
Reflow or Soldering Circuit Connections
12 minUse a fine-tip soldering iron and desoldering braid to re-solder or replace defective micro-components on the board.
- 14
Clean PCB Surface
3 minClean remaining flux residue off the board using high-purity isopropyl alcohol and a lint-free swab.
- 15
Reinstall Logic Board into Frame
3 minAlign the logic board with the phone frame guide pins and gently press it back into place.
After your Motorola Moto E40 logic board repair
Power the Moto E40 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 Motorola Moto E40 job before assuming the part is defective. Keep leftover adhesive and screws labeled in case you need a second pass.
Keep learning
Explore more Motorola Moto E40 repair context in the encyclopedia, or open related DIY guides.
