The system took a lightning strike a couple of weeks ago that re-set programming to default and took out the maintenance port.
I replaced the DXCPU and was able then to get into the program mode and restore program from backup.
After doing this I found that several exts. had distorted transmission on handset and speakerphone. All of these exts. were on the same DXDST-16 card which is in UNV slot 6 of the expansion cabinet. I have verified that the problem is in the KSU and not the cabling. I have replaced the DXDST-16 card but that did not clear trouble. All of these are in a remote building that was closest to the lightning strike. I have replace surge protection on both ends of cable since I found a couple of bad protectors that had 2 stations totally dead.
I suspect one or both of the interface cards. Any suggestions? Thanks!