How many station cards do you have? That's a pretty big system to only have two working phones. Have you tried moving KIB cards around to get more of them working? The one farthest to the left begins with X100 and each card provides service for 12 stations. If you don't have spare KIB's to swap, they are relatively inexpensive on the secondary market, in fact I believe I have a few left if you need to rent one to test. They also aren't expensive to have repaired.

Ed Vaughn, MBSWWYPBX