KVM 16-port switch - no video for server

[needhpinnc]

Using a P/N 336045-B21, 16-port KVM switch, with HP DL385 Gen8 server. Screen worked at the beginning of ILO setup, then later was blank. I can see server screen remotely through ILO on http (.net console) but not at server KVM.  Using USB adapters to connect server to KVM switch.

Is this possible a video driver issue with KVM? DO I need to update firmware on KVM and on USB adapter? They are about 7 yrs old. Can this be done without disturbing live servers already running and connected to KVM switch?

Any solutions are greatly appreciated. 

P.S. This thread has been moevd from Switches, Hubs, Modems (Legacy ITRC forum) to Servers > general. - Hp forum Moderator