2. Service
Functional-Group-Diagnostic Trees (Diagnostic Section 2)
77
RF-Chain Diagnostic Tree
(Functional-Group Subsection 3)
This subsection describes the RF-chain diagnostic tree for the
5071A Primary Frequency Standard and provides fault isolation of, or
pointers to diagnostic trees for, constituent RF-chain assemblies or modules.
2.3.1.0 RF-Chain Test Start Up
1 Remove power by disconnecting external ac and dc power.
2 Ensure that the internal-standby battery packs are disconnected.
3 Wait at least one minute for A16 high voltage supply to bleed down.
4 Disconnect semi-rigid coax from cesium-beam tube.
5 Connect this free end to the spectrum analyzer with an SMA female-female
barrel and the Microwave Test cable for use at 9 GHz.
6 Disconnect right-hand CBT cable (viewed from front) from A2J2.
7 Go to, 2.3.2.0.
2.3.2.0 9192 MHz Signal-Spectrum Test
1 Set input attenuator on HP/Agilent 8566 microwave spectrum analyzer for a
maximum input level of +10 dBm (Must be done
before #2).
2 Reconnect external ac (or dc) power.
3 Verify that instrument powers up and goes into Fatal
Error mode.
4 Set spectrum analyzer for a center frequency of 9192.0 MHz and
a span of 5 MHz/division.
5 Verify presence of a single carrier signal with amplitude at least -3 dBm.
(Include the microwave test cable loss in your calculations.).
QUESTION: Is a single carrier signal present with an amplitude
of at least -3 dBm?
If Yes: Go to, 2.3.3.0.
If No: Go to, 3.6.1.0 (A15 Diagnostic tree).
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