First, it has been years since I did any network admin work, and never with that KVM switch. So take what I say with a 50lb bag of salt and note I basically am just thinking out loud.
I note the manual says, the blinking power LED means it is either booting OR there is an upgrade in progress. I wonder if it is trying to upgrade and the process is corrupt? Any idea as to why the seller sold it? The manual also says, disconnecting an IQ module or power cycling a the target device during a firmware update will "render the module inoperable" and will require it be sent back to the factory for repair. 
Have you tried connecting via Ethernet to view the menu over a network? When you say you get "no sign of any information that the unit is booting. No logo, no text." Do you see anything?
