IP Console Switch 2x1x16 no video

[Huog]

Hi,
I've a problem with my KVM-Switch. I tried to conntect some servers via Expansion Module to the KVM, but I don't get any video. I conncted another LCD to the front-vga-interface of the server, and I saw, that the KVM receives my mouse and keyboard inputs. I only don't get any video.
I tried some steps:
1. I updated all firmware. KVM and IAs
2. I tried to connect one of the problem servers to the KVM directly (without the expansion box)
3. I replaced the IA.
4. I tried another ports.
5. I replaced the Expansion box.

There is no solution. I already called the HP Service, but they don't have any idea.

Is it possible, that I have to configure something in the KVM-Switch? All other servers work fine. Only seven Server make a problem. We drive about 40 servers with this KVM-Switch

Can anyone help me? Thx!