Is the entire display dead? If so... see this FAQ that GHTROUT wrote. Here's a quote from it:
"If you play in the Customer Data Block and type the word “Yes” in response to OPT, the digital displays on the consoles will stop working. Take a look at your telephone dial and notice the letters YES and XDP (eXclude Digit disPlay) share the same numeric dial digits. To turn the display back on, type IDP at any OPT prompt in the Customer Data Block"
It's in the Attendant Console FAQ in this forum. That may be your problem.
~M
Matthew Heavner
Field Service Engineer