Hello Thierry,
please note that the power supplies need a minimum load on the first channel.
If you use the RT-50C you have to have a (dummy)load of 0.5A on the +5V channel.
All other channels are depending on the first channel with his voltages.
I make this experience with an triple voltage Meanwell with an CRT chassis i want to supply from the +12V channel.
Every time the 3.5" floppy drive on the +5V channel steps, the display area on the screen shrinked and grows with stepping.
So i use a single +12V pwer supply, which is regulated from the +12V.
Frank