Alright so I went to the drawing board and downloaded board diagram to check the current flow in the device because I heard a hum with the device plugged into the screen, and then a ten year old lesson from Electrical Technology hit me - humming is frequently transistor undercurrent - not what I was thinking as a ground fault. The device had intermittent power failure under random circumstances - all of which I deduced was from the CPU or HDD drawing any sort of actual current rather than standby levels.
The end result was going back to drawing board and assuming my colleague was a total doofus and did a half-hearted Dx.
I went back to point A and tested the AC, then tested DC volts which were spot on at 19.1V, and then I decided to check out the current levels and the DC current was jumping all over between 0.01-1.19A
The dang charger was bad, and the colleague ordered batteries and sent it uphill for major board level testing without doing the basics.
Never forget to literally listen to you PCBs in the event of power issues - whining is too much Amps and humming is too few, transistors like the proper numbers