Dell laptop (E7440, uses the notorious CD3301B power controller + MEC5075 EC + BQ24715 charger IC)
Symptoms:
  • Laptop works normally on a pre-charged battery.
  • Battery does not charge when adapter is connected.
  • Without battery:
    • Laptop powers on from DC adapter, passes CPU/RAM init checks, then cuts DC power abruptly.(seems to shutdown one of the mosfets in the charger path). Then the loop continues indefinitely
    • Speakers “pop” when power cut occurs indicating harsh sutdown.
    • If RAM is removed, the system shows RAM missing blink error code indefinitely without cutting DC power
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