A40

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Overview[edit | edit source]

ZXW: Board only

Device types:

  • A405FN
  • A405FM
  • A405S

Common isses[edit | edit source]

Problem Solution
No power. No charging. Symtoms:
  • Display shows black screen
  • Phone won't even register DFU over USB
  • Low amperage draw (approx. 60mA) when supplied through battery connectorSolution:
  • Sometimes shorts develop slowly but even those "half-shorts" can prevent a phone from booting
    • Place device under thermal camera. Look for a thiny thermal spot when powering the device.
      • In this case a heat spot showed on U1008. Remove/replace U1008 and device works again.

Diode measurments[edit | edit source]

Voltage rails[edit | edit source]