Hmm,
Do you see anything abnormal in the electical cabinet? LED's that aren't on, etc?
That early in the bootup, I'd wonder perhaps about the PC type power supply failing.
With the power completely off, pull and reseat all the connectors that you can, and check all screw terminal connections for tightness. Gently pull on the wires first to see if you can find an actual loose culprit.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)