A1200 flickering in screen

[amiga4001]

So I got me a "new" 1200 but while loading of disk or harddisk there is a flickering in the screen.
Looks like a loose contact antwhere on the mobo.
Tried a other psu same thing.
Tried without hd still flickering while loading of diskdrive.
Resoldered the plug on the mobo still same.
Can it be the plug on the mobo itself as when I rock it while running power falls away?
Or is the plug always that fragile?
A1200 rom 3.0 rev .10 60 MB 2.5 inch with A1200psu

[amiga4001]

Ok an update.
I wired a AT psu to the mobo with the GND +5V +12V and it booted nicely without the striping/flickering.
So I thought it must be the contraplug of the mobo.
Replaced that with one out of a A500 but same problem.
Could it be the mobo is just taking to much current out of the original psu?
As for revision no not .10 but 1D..? can't remember rest.