Testing APU for failure

Is there a way to test the APU for failure, I get all necessary voltage in standby and when switched on but only get a long blue light but never turns white.

Another thing I noticed when checking out for liquid metal at the APU was chipping along one corner, I have seen this in another board I have for repairs, is this an APU failure, or part of the heat sink for the chip? the top part that looks like black hole is some liquid metal on top of chip.

Corner of the chip.