With so many with the same issue - over and over again - here's why
the AC Adapters / Motherboards for a range of DELL Laptops keep dying.
The design of the hardware circuitry for identification of the DELL AC Adapter is seriously flawed. The root cause is the use of an UNSHIELDED cable between the controller chip on the Mother board and the ID chip pin in the AC adapter.This unshielded lead acts as an ANTENNA
and easily picks up electro-magnetic pollution going straight to the chip circuitry. The hardware circuitry is not hardened to deal with electro-magnetic fields.
Consequently this energy is dissipated in the chips on each end of the lead ruining either one chip or both chips if the electro-magnetic spike was powerful enough.
So use warranty to the max, this is a serious design fault. If outside warranty consider using a shielded lead or try to stay away from strong electromagnetic fields / switching.
Here's the full story:
My 2 cents,