Citation
Abstract
The reliability of the Data Decoder Assembly (DDA), although improved by a series of engineering change orders, continues to exhibit a failure rate higher than desired. During the past year, the major source of intermittent problems has shifted to the interface assembly which includes the couplers that provide the interfacing between the Interdata 4 and other station equipment. A mechanical stabilizer design was implemented in the DSN to inhibit physical movement in the interface assembly. Interdata power supply problems had been involved in an increasing number of failures reported on DDAs. Several modifications have been and will be implemented to correct these problems. The lack of test software has complicated troubleshooting because either operational software had to be used or individual test software programs had to be developed at the stations. To rectify the dearth of test software available, the original test software was revised and updated to help station personnel troubleshoot an assembly in its operational configuration. Several corrective actions are in the process of being developed to prevent loosening of integrated circuits and platforms on couplers, to modify and/or replace computer power supplies, and to improve noise immunity in some coupler circuits. The DDA “‘halt’’ problem has been irritating to operations. Although a low level of investigation has been going on for over a year, insufficient information has been provided to identify this “‘halt’’ problem. The plan for improving the reliability for Viking support includes the addition of personnel to devote full time to the DDA problems, closer interfacing between operations and engineering to identify and define problem areas, and development of a tester to allow off-line testing of DDAs to isolate hard faults to replaceable modules in the minimum time possible consistent with required Viking support.
Details
- Volume
- 42-28
- Published
- August 15, 1975
- Pages
- 78–82
- File Size
- 631.4 KB