MBP turns black and stays blocked. Power loss

Hi

My MBP switches suddenly off, black screen and not a single status light nothing.

This happens significantly when i shake the book or when i tap with my fingers on top of the book .

Or when i move the book around

After that the only way to wake the macbook is to open the case and disconnect the battery for 10 sec.

I tried PMC reset everything nothing helps.

I tried removing the RAM for proper connectivity,

plugged all cable on the motherboard in and out .

Finally i replaced the harddisk. still no success.

Is the motherboard broken or is this a cable connectivity issue ?

Has it to do with the power source circuit ?

Many thanks for your help

Andy H. Switzerland Europe