Yellow submarine.
I did do more measurements.... I did fire up my HP 6632A System DC supply for a first time I don't know how many years. It sounds like a fighter jett and have pita UI for quick electronics twidling. Anyway it should be good quality equipment.
Dang... Still there.
Hmm, I have Tandar still turned on, but not connected to anything else than mains socket.
https://www.eevblog.com/forum/metrology/oh-no!-i-got-infection/?action=dlattach;attach=333158
Uh.. It might be not be ... How the heck.. HP is turned Off, but signal is from HPs output terminals.
https://www.eevblog.com/forum/metrology/oh-no!-i-got-infection/?action=dlattach;attach=333160
Yep it definedly is the Tandar supply. Tandar is out of socket.
https://www.eevblog.com/forum/metrology/oh-no!-i-got-infection/?action=dlattach;attach=333162
Some more repair work ahead, before my voyage to the ppm DC world can continue. First check - bridges and caps... But that is another fairy tale to different section. HP doesn't look partially clean either, but It didn't have any load and I can not remember the specs.
PS. Opened the Thandar and what I did found, the logic 5V / 5A DC part (as this is triple supply ~11 kg ) is definedly a switchmode supply after the (I suppose ) isolation transformer there is so many tuning and power coils that it can't be any other type than that, side cutters are my friend tomorrow then it is only a matter of a new powerswitch to turn off the noisy part, when not needed (=99.95% of times). Problem solved for now .. I hope.