This is the troubleshooting I've done so far:
- When I press the power button, the power light on the left of the device flashes very briefly once, but inconsistently.
- When attached to a power adapter, the power LEDs at the power button and the side blinks three times and then indicates charging/full charge with an organge or white light.
- The BIOS chip has power and clock.
- Continuity check on the flex cable pins shows the power button works.
- Detaching other components does not help.
- The usual tricks such as pressing the reset button or detaching/re-attaching the battery do not help.