MAINTENANCE
Common Control Problems
Common Control circuitry is difficult to troubleshoot. The system must be powered down before any of these CPs are replaced. Before powering the system down, save translations to tape (see “Using the Digital Tape Unit”). Other repair procedures may also require the system to be powered down. After removing a suspected faulty CP, do the following:
●Visually inspect the CP. If a problem is identified, attach a note to the CP identifying the problem.
●Attach any error reports that may apply.
●Visually inspect the cabinet backplane.
After the suspected faulty CP has been replaced, the system can be powered up. When the CPU/Memory CP is replaced, all historical data is lost. The system will then have to be restored from the tape backup unit with the latest copy of the system’s translations. If no tape exists, the system has to be reinitialized.
Multiple errors and
