@cas said in Omega2+ losing power / powering off unexpectedly:

The pin pad underneath: <photo>

"Thermal pad is connected to GND layer through vias (recommend 4X4 pins and the aperture is 10mil)." /active-semi/

These holes are (thermal conducting) vias between the top and the bottom copper layers of the PCB.

The bottom of the dock was very hot to the touch, so I suspect I burnt out the ACT2801 which appears to have a pin pad underneath. Actually upon closer inspection of the pin pad, one if the holes appears to be blocked with a silver substance and I can't help wondering if that's solder (if that's at all possible).

Spot the mistake.... ;-)

It's a "perfect" solder material "bead" / "ball" - it's OK here - no problem.

I don't have Power Dock - so I'm speculating based on active-semi's ACT2801 data sheet and Onion's schematics only.

VIN Input Voltage nom. +5V (range +4.5 ... 5.5V), Absolute Max. +6.5V
VIN_OVP Over Voltage Protection typ. +6.0v (range +5.5 ... 6.5V)
So 5.4V was OK.

The IC has an Input Current limiter.
ILIM Input Current Limit - Omega's setting is R2=2.4kΩ about 1A - so the input current couldn't have been more than 1A. (It was 1.8A / 1.9A!)

Please try to recall. You might have done something else or something else might have happened.

Or simply this is one of those cases where Murphy's Law happened to be working.