ECAM 23 450S, water ends up in drip tray instead of

Hello,
With my old Delonghi ECAM 23 450S, some of the water ends up directly in the drip tray instead of in the coffee, as far as I've read there are two causes, the upper solenoid valve or the upper brew group, can you narrow it down further or does it only help to replace at good luck?
I opened the coffee machine and to test the upper hose marked red in the picture times pulled off and put a measuring cup under it. Already when switching on comes out there ne small amount of water, that seems normal, but what bothers me are the 40-50ml that come out during the brewing process there.

Here still the picture the water exits at the red star, the inflow occurs at the blue star through the hose from the upper solenoid valve.

Usually the upper brewing piston is defective. But would replace both parts, then you can be sure. The solenoid valve does not cost the world.

Hello,
I had almost counted on it, then I will get me both parts and exchange in the hope that the machine creates another 10 years...