No image on Tv on V1 Dock, but works with a new Oled Dock some minutes

Hello community,

so I have a weird Problem with my Switchs.

I have a V1 Switch with its own Dock and a new Oled Switch with its own Dock too.

Now if I want to use my V1 Switch with V1 Dock. I got no image on the Tv. Charging works. Screen from Switch goes dark. When I plug it into the new Oled Dock. It works. At least for couple videos. So the first idea would be, that the V1 Dock does not work. But when I plug my Oled Switch to the V1 Dock it works?!?

So where does the fault is. Besides I noticed that on the Oled Dock the V1 Switch does work for a couple of minutes. After that. It also goes blank.

Initiliazed the switch new. Turned it on and off. Updated the dock. So no obvious reason. Usb c port looks fine on both. Switch and dock. Where should I look for problems on the board. I have a MM and can check for obvious reasons. For example filters are ok and no short near the hdmi chip.

Thank you.