The computer display has gone blank. All the fuses in the back are working, none of them have blown, but there appears to be a connection problem with the DeviceNet. The manuals explain little of how to resolve this issue, so I was wondering if I could have some input on what could be wrong.

A while ago someone came in to fix the turret inside, and since then nobody has seen the machine in operation, although while he was repairing the turret the machine was operational.