2. Service
Top-Level Diagnostic Tree (Diagnostic Section 1)
42
1.0.8 5071A Profiling
Successful completion of the preceding tests indicate that all functional
blocks of the 5071A under test are operational. This is confirmed by the
instruments' ability to lock-up its servo loops successfully with no errors.
These tests are however, not sufficiently detailed to predict the accuracy or
stability of the instrument, which could be degraded by noise or instability in
the CBT and the electronic circuits.
Because the operating accuracy and stability of the 5071A can only be
confirmed by long observations, it is useful to assess the noise contribution of
the CBT at the completion of the top-level test procedure. The CBT has a
finite lifetime, and measurements of its operating parameters may be used to
give advanced warning of required service.
1
Perform the 5071A profiling procedure provided at 1.6.0. The procedure has
no effect on the timekeeping performance of the instrument, and may be
conducted on an 5071A currently in use. The procedure requires only that the
instrument will run in Normal Operation mode.
2
When the profiling software has generated its report, use the following
information to evaluate the results.
1.0.8.1 Profiling Results Interpretation
Signal to Noise Ratio
The
Signal to Noise Ratio
is an estimate of the current overall operating
condition of both the CBT and instrument electronics.
•
If the result is
Band 1
, the instrument's stability should meet specification.
CBT problem is unlikely.
•
If the result is
Band 2
, the test is indeterminate. High Probability that
CBT is performing to specifications.
•
If the result is
Band 3
, instrument stability will probably not meet
specification. CBT problem is likely. Consult Chapter 1 on Performance
Tests to confirm poor performance.
Depth of Modulation
The Depth of Modulation can help isolate faults to either the CBT or
instrument electronics.
A Band 3 modulation depth combined with a peak-output current below 100
nA indicates deteriorating CBT performance. Be sure to thoroughly diagnose
the entire instrument before considering the A17 CBT to be at fault. Contact
your nearest service facility for further assistance.
Содержание 5071A
Страница 2: ......
Страница 40: ...1 Performance Tests Verifying Specifications 5071A Complete Performance Tests 24 ...
Страница 48: ...2 Service Pre Troubleshooting Information 32 Figure 2 1 Instrument Top View ...
Страница 147: ...3 Theory of Operation Functional Block Descriptions 131 Figure 3 2 5071A Overall Block Diagram ...
Страница 148: ...3 Theory of Operation Functional Block Descriptions 132 Figure 3 2 5071A Overall Block Diagram Continued ...
Страница 164: ...3 Theory of Operation Functional Block Descriptions 148 Figure 3 3 A1 Power Supply Distribution Schematic Diagram ...
Страница 166: ...3 Theory of Operation Functional Block Descriptions 150 Figure 3 4 A1 Slot Module Interconnect Diagram ...
Страница 168: ...3 Theory of Operation Functional Block Descriptions 152 Figure 3 5 Power Supply Block Diagram ...
Страница 171: ...3 Theory of Operation Functional Block Descriptions 155 Figure 3 7 Opt 048 A1 Slot Module Interconnect Diagram ...
Страница 172: ...3 Theory of Operation Functional Block Descriptions 156 Figure 3 8 Opt 048 Power Supply Block Diagram ...
Страница 173: ......
Страница 175: ...3 Theory of Operation Functional Block Descriptions 159 Figure 3 9 A1 Component Locator Diagram ...
Страница 194: ...5 Replaceable Parts How To Order A Part 178 ...
Страница 197: ......