Charging disappears when turning on

[siem3]

Device: HP Pavilion laptop — 15-dk0136tx (1660 Ti + i5-9300H, 32 GB RAM)

Main symptom:

• When the laptop is powered off and the AC adapter is connected, charging takes place and the charging indicator is lit.

• When the laptop is turned on, the charging indicator goes out, the laptop switches to battery power, and the battery begins to discharge. No AC power is supplied.

Repair history and attempted solutions:

• First service visit: Specialists reset the BIOS settings and reconnected the power cable several times. After that the laptop turned on, AC power was restored, and the battery charged. At home, additional reboots and a BIOS reset were required afterwards, after which the laptop worked from the wall outlet. The symptom was intermittent: after moving to different rooms and several power-off/power-on cycles, it worked normally. Later the problem returned to its original state.

• Second service visit (different technician):

  • Tested the power adapter – it is working.

  • Continuity test of the motherboard power circuit without load – no faults were found.

  • Assumptions were made: either a battery fault (its controller) or a firmware failure of the power controller (EC). It was noted that they do not have a programmer for reflashing. The laptop was returned without repair.

• Consultation with the seller: The seller claims the problem is with the battery.

• Information analysis (neural networks, forums): Based on the overall symptoms (“charging disappears only when turned on, but is present when off”), a fault in the power circuits on the motherboard (power controller, MOSFET switches, microcracks) is considered more likely than the battery itself, but the defect persists when the power circuits heat up.
  
  I updated the drivers, removed the battery driver, updated the BIOS, and UPDATED EVERYTHING.