Hi Everyone! I'm back...
We did the experiment with only the power-supply and the Eth plugged in and the results is the same. After an hour the heat switches in.
He said he don't know if it was an original problem or not because the early experiment periods never went over an hour, until one day he decided to attempt a 3D project which catered for a period of 4hrs plus. It was at that time he discovered the problem.
I guess there is very little I can do about that now because I'm now the new owner of the CNC in question.
I recently bought it from him as is.
I guess I'll have to locate a new controller, if my projects are going to cross an hour in milling time.
Thanks you guys for all the assistance given.
Respectfully.
Fretty.